Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle

Masato S Abe; Kentarou Matsumura; Taishi Yoshii; Takahisa Miyatake

doi:10.1371/journal.pone.0245115

. 2021 Jan 14;16(1):e0245115. doi: 10.1371/journal.pone.0245115

Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle

Masato S Abe ¹, Kentarou Matsumura ², Taishi Yoshii ³, Takahisa Miyatake ^2,^*

Editor: Henrik Oster⁴

PMCID: PMC7808652 PMID: 33444354

Abstract

Many species show rhythmicity in activity, from the timing of flowering in plants to that of foraging behavior in animals. The free-running periods and amplitude (sometimes called strength or power) of circadian rhythms are often used as indicators of biological clocks. Many reports have shown that these traits are highly geographically variable, and interestingly, they often show latitudinal or longitudinal clines. In many cases, the higher the latitude is, the longer the free-running circadian period (i.e., period of rhythm) in insects and plants. However, reports of positive correlations between latitude or longitude and circadian rhythm traits, including free-running periods, the power of the rhythm and locomotor activity, are limited to certain taxonomic groups. Therefore, we collected a cosmopolitan stored-product pest species, the red flour beetle Tribolium castaneum, in various parts of Japan and examined its rhythm traits, including the power and period of the rhythm, which were calculated from locomotor activity. The analysis revealed that the power was significantly lower for beetles collected in northern areas than southern areas in Japan. However, it is worth noting that the period of circadian rhythm did not show any clines; specifically, it did not vary among the sampling sites, despite the very large sample size (n = 1585). We discuss why these cline trends were observed in T. castaneum.

Introduction

Latitudinal clines are of evolutionary interest because they indicate the action of natural selection [1]. Many traits correlate with latitude, for example, body size [2, 3] and life history traits [4]. Circadian rhythm traits are also correlated with latitude [e.g., 5–8].

Circadian rhythms are particularly important for timing or regulating key biological events in insects [9]. The free-running period and power (i.e., sometimes called the amplitude or strength of the rhythm) are characteristics of rhythms [10, 11], and there is much evidence that the free-running periods of circadian rhythms exhibit latitudinal or longitudinal clines at the phenotype to molecular levels in many taxonomic groups [8, 12–21].

In insects other than Drosophila, many studies on the relationships between free-running periods and latitude have been conducted. In the linden bug, Pyrrhocoris apterus, higher-latitude populations are reported to have longer free-running periods [14]. Similarly, a positive relationship between latitude and period has been reported in a parasitic wasp, Nasonia vitripennis [15], and also in plant species [16].

In Drosophila species that evolved in tropical regions and then expanded their distribution to temperate regions, rhythm traits vary depending on latitude [17]. For example, pupal-adult eclosion rhythms in the far north were more arrhythmic than those in the south among Drosophila littoralis populations [18]. Circadian locomotor rhythms of D. melanogaster derived from Africa had a stronger power of rhythm than those of more northern Drosophila species in Europe [19]. The frequency of the timeless allele encoding a long TIMLESS (TIM) isoform, which has spread in Europe, studied from 40° to approximately 65°in latitude was negatively correlated with latitude, i.e., higher frequency at lower latitude [5].

In addition, a pioneering study revealed a positive relationship between the strength of rhythm and latitude [7], while recent studies revealed a negative relationship between them [5, 6, 8]. Overall, these studies reveal that this topic remains controversial, and thus we will compare and then will discuss for the present results with other studies.

Given these discrepancies, we need more biological models. The red flour beetle Tribolium castaneum (Herbst) [Tenebrionidae] is a cosmopolitan stored-product pest [22], and hence, it can serve as an insect model insect species. Its biology and behavior are well studied [23, 24]. Furthermore, genome sequences are available for Tribolium castaneum [25].

This species is found throughout most of Japan, except for the northern island of Hokkaido, meaning that it can be collected in a wide range of latitudes [26]. It provides us with a novel, fascinating model with which to examine the relations between latitude/longitude and circadian rhythm traits. Hence, we studied the relationships between latitude or longitude and circadian rhythm parameters, including the period of circadian rhythms, power of the rhythm, and locomotor activity, in T. castaneum.

Materials and methods

Insects

The geographical populations of Tribolium castaneum used in the present study were collected from rice mills located at 38 different fields in Japan (Fig 1). S1 Table shows the latitude and longitude of the collection points, along with the number of samples. The northernmost and southernmost points where the insect could be collected were Aomori Prefecture (E127°69’ N40°89’), and Kumamoto Prefecture-C (E130°66’ N32°57’), respectively. The insects were collected during 2016 and 2017. We collected beetles from coin-operated rice pearling mills in Japan that were set up in villages or towns with rice fields. More than twenty beetles were collected from each mill.

Fig 1 — This map was drawn from a free map of Japan on a net site (https://frame-illust.com/?cat=256), and thus it was not necessary to obtain permission.

The collected beetles were reared with a mixture of whole meal (Yoshikura Shokai, Tokyo) enriched with brewer’s yeast (Asahi Beer, Tokyo) and maintained at 25°C with a 16 h photoperiod (lights on at 07:00, lights off at 23:00). These laboratory conditions closely resemble natural conditions of this stored product pest. Each collected group was kept in a separate plastic Petri dish (90 mm in diameter, 15 mm in height). Before the experiments, each beetle population was reared for more than two generations in incubators (MIR-153, Sanyo, Osaka, Japan).

Ethical note

The populations of T. castaneum used in this study were collected from each rice mill located at 38 different fields in Japan. The rice mills have signs saying “Feel free to take the rice bran.” so we didn’t need a permit to collect it from these mills. These laboratory conditions closely resemble natural conditions of this stored product pest. All individuals in the experiment were handled with care and handling time was kept to an absolute minimum. The use of these beetles conforms to the Okayama University’s Animal Ethics Policy.

Locomotor activity

To assess circadian rhythmicity, we maintained beetles under 16L:8D conditions for more than 20 days in an incubator kept at 25°C before the measurement of locomotor activity, and we then measured the locomotor activity of T. castaneum for 10 days in darkness. A beetle from each population was placed in a clear plastic Petri dish (30 × 10 mm) in an incubator (MIR-153, Sanyo, Osaka, Japan) maintained at 25°C under complete darkness (DD). We measured the circadian rhythms of 17 to 128 individual beetles for a single population. The sample size of each population measured for circadian rhythm is shown in S1 Table. The locomotor activity of each individual was monitored using an infrared actograph. An infrared light beam was passed through a clear Petri dish, and the beam was projected onto a photomicrosensor (E3S-AT11; Omron, Kyoto, Japan) that detected all interruptions of the light beam. Signals of interruption of the infrared light beam were recorded every 6 min [11]. At a time, we monitored 128 individuals, meaning we are measured 128 sensors at the same time.

Statistical analysis

To determine the circadian rhythm, the locomotor activity data collected for 10 days in constant dark conditions were analyzed. The free-running period of circadian rhythms was established using a χ2 periodogram test [27] for data on locomotor activity between 20 and 28 h [28]. Circadian rhythmicity was determined using χ2 periodogram analysis, and “power” was used as an index of the strength of rhythms. The power of circadian rhythms was defined as the maximum difference between the χ2 value and the significance threshold line at P = 0.05, that is, the size of the peak above the 5% threshold; see Fig 1 in [28]. Power is high when the rhythm is clear and strong, and a power of less than 0 indicates a statistically arrhythmic state. Moreover, total activity was calculated as the total number of interruptions of the infrared light over 10 days. To analyze the effects of latitude and sex on the period and power of the circadian rhythms and total activity, we used GLMs with Gaussian link functions. All statistical analyses were performed in R version 3.4.3 [29].

Results

First, we analyzed the relationship between the geographical area and the power of the rhythm. To avoid multicollinearity between latitude and longitude (the correlation coefficient (r) between them was 0.83), we didn’t include both simultaneously in the model as an explanatory variable but constructed a separate model with each value.

The GLM results revealed a significant relationship between latitude and power (Table 1, Fig 2A), while sex was not significantly associated with power (Table 1). The estimated coefficient for latitude in the model was negative, suggesting that the higher the latitude was, the weaker the rhythm was. For longitude, we did not find a significant relationship (Table 1, Fig 2B).

Table 1. Statistical test results.

Coefficients and standard errors obtained from GLM analysis are shown.

	Response variable
	Power of rhythm		Period of rhythm		log(Total activity)
Latitude	-2.356^*	-	-0.572	-	0.068^**	-
	(-1.083)	-	(-0.435)	-	(-0.023)	-
Longitude	-	-1.126	-	-0.288	-	0.023
	-	(-0.629)	-	(-0.253)	-	(-0.014)
Sex (male)	-23.145	-1.303	3.441	30.986	2.408^*	3.239
	(-54.072)	(-118.738)	(-21.737)	(-47.701)	(-1.159)	(-2.549)
Latitude × sex (male)	0.753	-	-0.133	-	-0.057	-
	(-1.519)	-	(-0.611)	-	(-0.033)	-
Longitude × sex (male)	-	0.037	-	-0.238	-	-0.021
	-	(-0.876)	-	(-0.352)	-	(-0.019)
Constant	54.626	123.33	257.799^***	276.420^***	4.523^***	3.884^*
	(-38.616)	(-85.312)	(-15.524)	(-34.273)	(-0.828)	(-1.832)
Adjusted R-squared	0.003692	0.00331	0.001649	0.002568	0.02959	0.02588

Open in a new tab

* p < 0.05;

** p < 0.01;

*** p < 0.001

The hyphen represents the explanatory variable not included in the regression model.

Fig 2 — The blue line represents the statistically significant regression line (p < 0.05).

Second, we investigated the relationship between geographical area and the estimated period of circadian rhythms. The statistical results yielded no significant relationships between them (Table 1, Fig 3).

Finally, we investigated the relationship between geographical area and total activity (Fig 4). Because the total activity had some outliers, we used log-transformed values. The results of the regression analysis showed that total activity was associated positively with latitude and sex (Table 1, Fig 4).

Discussion

In the present study, the power and period of circadian rhythms and total locomotor activity varied among geographical populations of T. castaneum. Circadian periods seemed to vary evenly between 20 h and 28 h (Fig 3). The present results showed that the power of circadian rhythms was significantly lower for beetles collected in northern areas than in southern areas (Fig 2). This result suggests that beetles collected from different parts of Japan have different characteristics. In this study, we reared individuals collected from the fields for a few generations in a chamber under the same environmental conditions in the laboratory before measuring their traits. Therefore, it is unlikely that the present results were affected by any maternal effects.

Although clines in the power of the rhythm have been observed in only a few species, the trend of weaker circadian rhythms in northern populations has been observed in other insect species. Specifically, a clear rhythm was shown at lower latitudes whereas no rhythmic activity was shown at higher latitudes in Hymenoptera and Drosophila species [30, 31]. The present results are consistent with the results of these previous studies. Why is the rhythm weaker at higher latitudes? One answer may be that in more extreme environments, it may be easier to survive with less restriction of activity by the clock and more control by direct environmental responses, namely, masking of circadian activity [32, 33].

On the other hand, positive relationships between latitude and the length of circadian rhythms have often been reported; higher-latitude populations are reported to have longer free-running periods [14–16]. However, in the present study, no significant relationship was observed between the period of circadian rhythms and latitude or longitude, despite the very large sample sizes. The present study sampled beetles in a range of approximately 9 degrees latitude (from about 32°N to 41°N). Previous studies ([21] and references therein) have often measured rhythmic traits beyond the current range, but period of circadian rhythm has not yielded a distinct cline within the range of the present study; i.e., there was no effect of longitude or the longitudinal range (about 10 degrees). In other words, within this range of latitude, the range does not show a constant trend depending on the insect species examined [8]. Therefore, it is possible that a cline could be detected if beetle samples from more north were available. Because the northern limit of this species distribution is in Aomori Prefecture (about 41° degrees in latitude) where we examined this species, it may be possible to survey this point if we use a closely related species, such as Tribolium confusum, which may also inhabits Hokkaido. In comparing clock clines among species, caution may be required, because different Drosophila species have different clock networks [8]. Circadian rhythm is also affected by annual patterns of climatic factors including twilight duration, photoperiod, and temperature [6]. We didn’t pay attention to the season when we were collecting beetles. However, our samples were maintained in a laboratory for two generations before use in the experiment, and thus we consider that such external weather effects could be ignored in this experiment.

The cline in the amplitude of the circadian rhythm in T. castaneum clearly suggests geographic variation. This result is very interesting considering the history of the controversy surrounding the dispersal distance of this insect, specifically, that studies do not agree on its dispersal characteristics. Some studies suggest that this beetle disperses very well [34]. Ridley et al. [34] inferred very high levels of active dispersal of T. castaneum through adult flight based on microsatellite genotypes. On the other hand, Drury et al. [35] and Arnold et al. [36] suggest limited dispersal for this beetle including short-range flying.

We considered two hypotheses regarding why no cline in the length of circadian rhythms was found in T. castaneum, as follows: bottlenecks and local adaptation. A small number of individuals or one fertilized female can enter and settle in individual rice mills scattered in the countryside [37]. A small number of T. castaneum will form each population within each mill. Predation pressures, including that from predator insects [38, 39], and the differences due to human cleaning will differ among mills. These pressures can cause differences in traits, especially in the activity traits, of T. castaneum. Such selection pressures (local adaptation) and founder effects (bottlenecks) would cause a large degree of variation among T. castaneum populations. T. castaneum cannot fly under stable conditions. Indeed, as described above, although these beetles have wings, dispersing by flying is rare at 25°C [35], with walking being the most frequent mode of travel [36], and walking is the mechanism by which males locally search for females [39]. Additionally, Semeao et al. [38] showed that populations of T. castaneum collected from mills showed a spatial genetic structure, indicating the occurrence of a recent bottleneck in some mills. Therefore, each mill used in the present study may be an ideal system to clarify the mechanisms of bottlenecks and local adaptation of creatures in that mill.

On the other hand, adults of T. castaneum are known to fly well at temperatures above 28°C [40]. There may be individuals flying beyond the area in the summer season in Japan. If gene flow is greater than expected, it might explain the lack of latitudinal and longitudinal clines shown in the present study. Ridley et al. [35] estimated the dispersal distance of T. castaneum using microsatellites and found that adults could fly at least 1 km per year in fields. They reported that T. castaneum aggregates predominantly around areas of grain storage but actively disperses by flight between these spatially separated resources [35].

Another study showed that genetic distance was not significantly correlated with geographic distance among T. castaneum populations in mills in the United States [38]. Semeao et al. [38] provided evidence that populations of T. castaneum collected from mills showed a spatial genetic structure, but the poor ability to assign individuals to source populations and the isolation at each mill suggested lower levels of gene flow than originally predicted. Konishi et al. [39] also suggested that different anti-predator strategies have evolved in each storehouse with and without predatory insects. These studies suggest that the dispute about gene flow or the possibility of evolution in individual storehouses in field mill systems will continue. The present result of a cline in circadian amplitude suggests that gene flow is not occurring on the spatial scale that we examined. However, estimation of the degree of gene flow between rice mills and phylogenetic relationships between populations within the species in Japan is required.

Notably, the results of the present study showed P values smaller than 0.05, even for small effect sizes, due to the very large sample size (n = 1585, total sample size). This suggests that the power of circadian rhythms is smaller at higher latitudes, but the difference is not large. Moreover, it is worth noting that the period of circadian rhythms does not change, even with the very large sample size, in this beetle species. It should also be noted that the negative relationship of power of rhythm to latitude, and the positive relationship of total activity to latitude in the present study may have detected significant effects despite the weak relationship due to the very large sample size (see Adjusted R-squared in Table 1).

Further studies on circadian rhythms at population and molecular levels (e.g., clines in alleles of specific circadian genes) are needed in the future [see 5, 6, 8, 17, 21]. Furthermore, given the seasonal differences in light exposure at different latitudes, studying the phase shift of the locomotor rhythm to brief light pulses might also provide a relevant phenotype that can discriminate between northern and southern population, as was the case for Drosophila timeless variants [21].

The frequency of the timeless allele encoding a long TIM isoform of D. melanogaster first studied from 40°N to 65°N was initially negatively correlated with latitude, but this trend was reversed in populations collected in extreme southern Europe (32–35°N) [21]. It turned out that the latitudinal cline was actually due to natural selection spreading the recently derived timeless allele in all directions from a point of origin in southern Italy, thereby generating a distance rather than a latitudinal cline. This ‘distance cline’ was confirmed by studying the timeless allele in the Iberian Peninsula [41] where the cline was reversed. These studies reveal that the history of genes that encode clinal characteristics also needs to be considered when attempting to interpret spatial distributions. Such historical perspectives may account for some of the contradictory results that have been generated in the geographical analyses of biological rhythm phenotypes.

Supporting information

S1 Table. Collection site of T. castaneum populations with latitude and longitude.

(XLSX)

Click here for additional data file.^{(12KB, xlsx)}

S1 Data

(XLSX)

Click here for additional data file.^{(95.3KB, xlsx)}

Acknowledgments

We appreciate Yusuke Tsushima and Kouhei Nakao for insect sampling.

Data Availability

All relevant data are within the manuscript and its Supporting information files.

Funding Statement

This work was funded from Japan Society for the promotion of Science, Award number 16K14810 and 18H02510.

References

1.Endler JA. Geographic Variation, Speciation, and Clines. Princeton University Press, Princeton, NJ: 7; 1977. [PubMed] [Google Scholar]
2.Coyne JA, Beecham E. Heritability of two morphological characters within and among natural populations of Drosophila melanogaster. Genetics, 1987; 117: 727–737. [DOI] [PMC free article] [PubMed] [Google Scholar]
3.James AC, Azevedo RBR, Partridge L. Genetic and environmental responses to temperature of Drosophila melanogaster from a latitudinal cline. Genetics, 1997; 146: 881–890. [DOI] [PMC free article] [PubMed] [Google Scholar]
4.Blackenhorn WU, Fairbairn DJ. Life history adaptation along a latitudinal cline in the water strider Aquarius remigis (Heteroptera: Gerridae). Journal of Evolutionary Biology, 1995; 8: 21–41. 10.1046/j.1420-9101.1995.8010021.x [DOI] [Google Scholar]
5.Kyriacou CP, Peixoto AA, Sandrelli F, Costa R, Tauber E. Clines in clock genes: fine-tuning circadian rhythms to the environment. Trends in Genetics, 24: 2007, 124–132 [DOI] [PubMed] [Google Scholar]
6.Hut RA, Paulucci S, Dor R, Kyriacou CP, Daan S. Latitudinal clines: an evolutionary view on biological rhythms. 2013; Proceedings of the Royal Society B, 2013; 280: 20130433 10.1098/rspb.2013.0433 [DOI] [PMC free article] [PubMed] [Google Scholar]
7.Pittendrigh CS, Takamura T. Latitudinal clines in the properties of a circadian pacemaker. Journal of Biological Rhythms, 1989; 4: 105–123. 10.1177/074873048900400209 [DOI] [PubMed] [Google Scholar]
8.Helfrich-Förster C, Bertolini E, Menegazzi P. Flies as models for circadian clock adaptation to environmental challenges. European Journal of Neuroscience, 2020, 51:166–181. [DOI] [PMC free article] [PubMed] [Google Scholar]
9.Saunders DS. Insect Clocks, 3rd edn Elsevier, Amsterdam: 2002. [Google Scholar]
10.Klarsfeld A, Leloup JC, Rouyer F. Circadian rhythms of locomotor activity in Drosophila. Behavioral Processes, 2003; 6: 161–175. 10.1016/s0376-6357(03)00133-5 [DOI] [PubMed] [Google Scholar]
11.Matsumura K, Abe MS, Sharma MD, Hosken D, Yoshii T, Miyatake T. Genetic variation and phenotypic plasticity in circadian rhythms of an armed beetle, Gnatocerus cornutus (Tenebrionidae). Biological Journal of the Linnean Society, 2020; 130: 34–40. [Google Scholar]
12.Lankinen P. North-south differences in circadian eclosion rhythm in European populations of Drosophila subobscura. Heredity, 1993; 71: 210–218. [Google Scholar]
13.Zhang Q, Li H, Li R, R H, Fan C, Chen F, et al. Association of the circadian rhythmic expression of GmCRY1a with a latitudinal cline in photoperiodic flowering of soybean. Proceedings of National Academy of Science, 2008; 105: 21028–21033. 10.1073/pnas.0810585105 [DOI] [PMC free article] [PubMed] [Google Scholar]
14.Pivarciova L, Vaneckova H, Provaznik J, Wu BC, Pivarci M, Peckova O, et al. Unexpected geographic variability of the free running period in the Linden bug Pyrrhocoris apterus. Journal of Biological Rhythms, 2016; 31: 568–576. 10.1177/0748730416671213 [DOI] [PubMed] [Google Scholar]
15.Paolucci S, Benetta ED, Salis L, Doležel D, van de Zande L, Beukeboom LW. Latitudinal variation in circadian rhythmicity in Nasonia vitripennis. Behavioral Science, 2019; 9: 115 10.3390/bs9110115 [DOI] [PMC free article] [PubMed] [Google Scholar]
16.Greenham K, Lou P, Puzey JR, Kumar G, Arnevik C, Farid H, et al. Geographic variation of plant circadian clock function in natural and agricultural settings. Journal of Biological Rhythms, 2017; 32: 26–34. 10.1177/0748730416679307 [DOI] [PubMed] [Google Scholar]
17.Kyriacou CP. Evolution: fruit fly clocks on the edge. Current Biology, 2017; 27, R227–R230. 10.1016/j.cub.2017.02.017 [DOI] [PubMed] [Google Scholar]
18.Lankinen P. Geographical variation in circadian eclosion rhythm and photoperiodic adult diapause in Drosophila littoralis. Journal of Comparative Physiology A, 1986; 159, 123–142. 10.1177/074873048600100202 [DOI] [PubMed] [Google Scholar]
19.Menegazzi P, Benetta ED, Beauchamp M, Schlichting M, Steffan-Dewenter I, Helfrich-Fõrster C. Adaptation of circadian neuronal network to photoperiod in high-latitude European Drosophilids. Current Biology, 2017; 27: 833–839. 10.1016/j.cub.2017.01.036 [DOI] [PubMed] [Google Scholar]
20.Pittendrigh CS, Kyner WT, Takamura T. The amplitude of circadian oscillations: temperature dependence, latitudinal clines, and the photoperiodic time measurement. Journal of Biological Rhythms, 1991; 6, 299–313. 10.1177/074873049100600402 [DOI] [PubMed] [Google Scholar]
21.Tauber E, Zodan M, Sandrelli F, Pegararo M, Osterwalder N, Breda C, et al. Natural selection favors a newly derived timeless allele in Drosophila melanogaster. Science, 2007; 316: 1895–1898. 10.1126/science.1138412 [DOI] [PubMed] [Google Scholar]
22.Champ BR, Dyte CE. Report of the FAO global survey of pesticide susceptibility of stored grain pests. In: FAO Plant Production and Protection Series, Food and Agriculture Organization of the United Nations, Rome.1976; 297 pp.
23.Sokoloff A. The Biology of Tribolium: v. 2: With Special Emphasis on Genetic Aspects. Oxford University Press, Oxford: 1975. [Google Scholar]
24.Fedina TY, Lewis SM. An integrative view of sexual selection in Tribolium flour beetles. Biological Reviews, 2008; 83: 151–171. 10.1111/j.1469-185X.2008.00037.x [DOI] [PubMed] [Google Scholar]
25.Tribolium Genome Sequencing Consortium. The genome of the model beetle and pest Tribolium castaneum. Nature, 2008; 452: 949–955. 10.1038/nature06784 [DOI] [PubMed] [Google Scholar]
26.Matsumura K, Miyatake T. Is there a genetic correlation between movement and immobility in field populations of a beetle? bioRxiv, 10.1101/2020.08.10.245431 [DOI] [Google Scholar]
27.Sokolove PG, Bushell WN. The chi square periodogram: its utility for analysis of circadian rhythms. Journal of Theoretical Biology, 1978; 72: 131–160. 10.1016/0022-5193(78)90022-x [DOI] [PubMed] [Google Scholar]
28.Halberg F. Chronobiology. Annual Review of Physiology, 1969; 31: 675–726. 10.1146/annurev.ph.31.030169.003331 [DOI] [PubMed] [Google Scholar]
29.R Development Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. R version 3.4.3. 2017.
30.Fleury F, Allemand R, Fouillet P, Boulétreau M. Genetic variation in locomotor activity rhythm among populations of Leptopilina heterotoma (Hymenoptera: Eucoilidae), a larval parasitoid of Drosophila species. Behavior Genetics, 1995; 25: 81–89. 10.1007/BF02197245 [DOI] [PubMed] [Google Scholar]
31.Joshi DS. Latitudinal variation in locomotor activity rhythm in adult Drosophila ananassae. Canadian Journal of Zoology, 1999; 77: 865–870. 10.1139/z99-051 [DOI] [Google Scholar]
32.Block G, Barnes BM, Gerkema MP, Helm B. Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value. Proceedings of the Royal Society B, 2013; 280: 20130019 10.1098/rspb.2013.0019 [DOI] [PMC free article] [PubMed] [Google Scholar]
33.Bertolini E, Schbert FK, Zanini D, Sehadová H, Helfrich-Fõrster C, Menegazzi P. Life at high latitudes does not require circadian behavioral rhythmicity under constant darkness. Current Biology, 2019; 29: 3928–3936. 10.1016/j.cub.2019.09.032 [DOI] [PubMed] [Google Scholar]
34.Ridley AW, Hereward JP, Daglish GJ, Raghu S, Collins PJ, Walter GH. The spatiotemporal dynamics of Tribolium castaneum (Herbst): adult flight and gene flow. Molecular Ecology, 2011; 20: 1635–1646. 10.1111/j.1365-294X.2011.05049.x [DOI] [PubMed] [Google Scholar]
35.Drury DW, Whitesell ME, Wade MJ. The effects of temperature, relative humidity, light, and resource quality on flight initiation in the red flour beetle, Tribolium castaneum. Entomological Experimental and Application, 2016; 15: 269–274. 10.1111/eea.12401 [DOI] [PMC free article] [PubMed] [Google Scholar]
36.Arnold PA, Cassey P, White CR. Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate. Functional Ecology, 2017; 31: 653–661. 10.1111/1365-2435.12772 [DOI] [Google Scholar]
37.Semeao AA, Campbell JF, Beeman RW, Lorenzen MD, Whiteworth RJ, Sloderbeck PE. Genetic structure of Tribolium castaneum (Coleoptera: Tenebrionidae) populations in mills. Environmental Entomology, 2012; 41: 188–199. 10.1603/EN11207 [DOI] [PubMed] [Google Scholar]
38.Konishi K, Matsumura K, Sakuno W, Miyatake T. Death feigning as an adaptive anti-predator behavior: further evidence for its evolution from artificial selection and natural populations. Journal of Evolutionary Biology, 2020; 33: 1120–1128. 10.1111/jeb.13641 [DOI] [PubMed] [Google Scholar]
39.Matsumura K, Miyatake T. Differences in attack avoidance and mating success between strains artificially selected for dispersal distance in Tribolium castaneum. PLoS ONE, 2015; 10: e0127042 10.1371/journal.pone.0127042 [DOI] [PMC free article] [PubMed] [Google Scholar]
40.Matsumura K, Archer CR, Hosken DJ, & Miyataka T. Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off. Behavioral Ecology, 2019; 30: 1522–1529. [Google Scholar]
41.Zonato V, Vanin S, Costa R, Tauber E, Kyriacou CP. Inverse European latitudinal cline at the timeless locus of Drosophila melanogaster reveals selection on a clock gene: population genetics of ls-tim. Journal of Biological Rhythms, 2018; 33: 15–23. 10.1177/0748730417742309 [DOI] [PubMed] [Google Scholar]

PLoS One. doi: 10.1371/journal.pone.0245115.r001

Decision Letter 0

Henrik Oster

9 Oct 2020

PONE-D-20-27518

Amplitude of circadian rhythms becomes weaker in the north, but there is no cline in the period of rhythm in a beetle

PLOS ONE

Dear Dr. Miyatake,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

In the discussion please elaborate on: What is the seasonal variation in photoperiod at the northern vs. southern end of the range? What are the typical temperature ranges? How does this compare with other studies in which circadian clines were or weren't found?

Fix issues with the Methods as indicated by reviewer 2.

Discuss the Helfrich-Foerster and Costa studies on weaker fly circadian rhythms in northern latitudes mentioned by reviewer 1.

Consider adding phase shift response data.

Discuss (small) effect sizes.

==============================

Please submit your revised manuscript by Nov 23 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Henrik Oster, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. In your Methods section, please provide additional information regarding the permits you obtained for the work. Please ensure you have included the full name of the authority that approved the collection sites access and, if no permits were required, a brief statement explaining why.

3. Please include your tables as part of your main manuscript and remove the individual files. ** Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files **.

4. Thank you for stating in your Funding Statement:

"This work was supported by the Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research Grants 16K14810 and 18H02510 to TM.".

i) Please provide an amended statement that declares *all* the funding or sources of support (whether external or internal to your organization) received during this study, as detailed online in our guide for authors at http://journals.plos.org/plosone/s/submit-now. Please also include the statement “There was no additional external funding received for this study.” in your updated Funding Statement.

ii) Please include your amended Funding Statement within your cover letter. We will change the online submission form on your behalf.

5. We note that [Figure 1] in your submission contain [map/satellite] images which may be copyrighted. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For these reasons, we cannot publish previously copyrighted maps or satellite images created using proprietary data, such as Google software (Google Maps, Street View, and Earth). For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

1. You may seek permission from the original copyright holder of Figure(s) [1] to publish the content specifically under the CC BY 4.0 license.

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

2. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

The following resources for replacing copyrighted map figures may be helpful:

USGS National Map Viewer (public domain): http://viewer.nationalmap.gov/viewer/

The Gateway to Astronaut Photography of Earth (public domain): http://eol.jsc.nasa.gov/sseop/clickmap/

Maps at the CIA (public domain): https://www.cia.gov/library/publications/the-world-factbook/index.html and https://www.cia.gov/library/publications/cia-maps-publications/index.html

NASA Earth Observatory (public domain): http://earthobservatory.nasa.gov/

Landsat: http://landsat.visibleearth.nasa.gov/

USGS EROS (Earth Resources Observatory and Science (EROS) Center) (public domain): http://eros.usgs.gov/#

Natural Earth (public domain): http://www.naturalearthdata.com/

6. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

Additional Editor Comments (if provided):

n/a

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is an interesting ms concerning the geographical variability of the circadian rhythm phenotype in T castaneum. The literature is mixed on this subject with classical Pittendrigh experiments in Drosophila species in Japan suggesting that the amplitude of the rhythm is stronger at higher latitudes because it has to counterbalance the effects of extreme photoperiods which would tend to make animals arrhythmic. There is not much molecular evidence to back this up, indeed recent studies from Helfrich-Foerster suggest the opposite, in that a weaker circadian rhythm in northern latitudes is more flexible for adaptation of circadian behavior to extreme photoperiodic conditions. Costa's group suggests that the circadian light response in D. melanogaster should be reduced at higher latitudes - this pair of papers (Science, 2007???) is not cited. Consequently it would have been nice if the study had also included a phase shift response to light as that would have been perhaps more relevant at these latitudes. Nevertheless, this study comes out in favour of the latter hypothesis. The results reflect a lot of work and the ms is clear to read and understand. My one quibble is that the effects are tiny and require a huge N to be observed. Also the variation in latitude is only 8oC which doesn't help to dissect out an effect. Furthermore the power statistic used is not very sophisticated and there are better methods available, but I suspect the result would be the same. The Discussion is a bit too long considering the brevity and conciseness of the results, so perhaps a little less speculation would be in order. Otherwise, the study is OK.

Reviewer #2: The authors conducted a study on the effects of geographic (primarily latitudinal) variation on circadian rhythmicity in the red flour beetle. Strengths of the study included the large sample size and rearing the populations for 2 generations in the lab to separate out maternal/environmental effects. While the English was professionally edited, I often found the ideas to be communicated in an imprecise or unclear manner.

1. It was completely unclear why the authors repeatedly referred to longitude early in the manuscript (e.g., L29, L40...a key word!, L47, L53, L78). The study is primarily designed to detect latitudinal clines given the much larger latitudinal range sampled. The authors state that longitudinal clines are also known (L47) but don't give a citation. Based on their titles, all the references cited on L54 (refs 8-12) refer to latitudinal clines. I can understand why they would want to test for this possibility within their data, but I don't know that there is any a priori reason to expect a longitudinal cline. This was also very confusing to me because they referred to altitudinal clines (L26 of abstract) making me think that maybe these would be investigated, but think they were ever discussed in the manuscript. A third point of confusion is that the authors said they were analyzing effects of temperature (L130), but I don't think they ever did.

2. The discussion on L61-69 is very unclear. The authors seem to be mixing points related to "where flies live" and latitude. By "where flies live" do they mean geographic features that might be distinct from latitude? If so what are they? L67 "pioneering"? Some of the studies cited here are quite old ("pioneering"). Is there a consensus emerging in the newer literature? The discussion overall was hard to follow.

3. The predominant finding of the paper was that there is an effect of latitude on amplitude/power of the circadian rhythm. This finding would be more useful if it were put into some kind of context. What is the seasonal variation in photoperiod at the northern vs. southern end of the range? What are the typical temperature ranges? How does this compare with other studies in which circadian clines were or weren't found?

4. While the sample size was apparently quite large, it was described in a very confusing way. For example, L109-110 makes it sound like only one beetle was measured per population. Maybe one was measured per population in each trial and several were monitored at once? L117/TableS1 is confusing because it sounds like it would be the number of beetles measured per population, but I think this is the starting population that was collected and used for breeding (??).

5. L113 the mention of "a clear Petri dish" again confused me...these are the same petri dishes referred to in L110, right? How many petri dishes were monitored at a time? Was there one animal in each dish? I was really confused.

6. L151-152. This description was inadequate. In what direction was the relationship, and how did it compare with the latitudinal effect on amplitude/power? I think this is important because total activity may affect the power to detect a change in amplitude or period (if animals aren't moving much it's harder to detect a change). Are these trends strong enough that such an indirect effect might be important?

7. L158 this statement is really vague. Are the authors talking about clines or just inter-individual variation? What are they trying to say?

8. L166-167 The transition to this sentence is really rough. "On the other hand" would usually indicate a contrast with the previous statement, which isn't the case here.

9. L176-177 This sentence seemed like an odd way to end the paragraph. And it is a sort of contrast to the opening sentence (L168-9). Why not combine them into one strong sentence at the beginning. Apparently, a limited number of studies have identified this trend. It's fine to just say that (once) and would be even better if the authors could put it in context. Are there just a few because it's only occasionally studied? Because most studies don't have sufficient power, or because it seems to be rare?

10. L188-194 This section again convoluted. L188-190 is a wordy sentence that should be streamlined/clarified. The examples should be clearly organized to indicate which support wide dispersal and which don't. My sense is that both Drury (33) and Arnold (34) suggest limited dispersal. This is obscured by the use of "on the other hand" which implies a contrast. On top of this the text about Semeao's study is repeated twice with very similar text (L195-197 and L233-237).

11. L252 I would argue that not only do they need molecular studies of the circadian rhythmicity (e.g., clines in alleles of specific circadian genes), but also to couple genetic studies (i.e. population assignment) more directly with phenotypic studies.

Minor

L51 "indicators of circadian rhythms" is vague. These are characteristics of rhythms, and variations in these characteristics could indicate adaptation etc.

L55 "Additionally" here doesn't make sense. The topic sentence makes it sound like they are switching to talking about "insects other than Drosophila" but the preceding paragraph is also mostly about insects and there is no mention of Drosophila.

L58-59 a positive relationship between "latitude and circadian rhythm" doesn't make sense. I think the authors might mean a positive relationship between latitude and period.

L75 The syntax is hard to follow. I suggest "This species is found throughout most of Japan, except for the northern island of Hokkaido, meaning..."

L89-91 Please write the coordinates in a more standard way.

L101-103 These two sentences almost completely repeat each other.

L106 "To assess circadian rhythmicity" or "To assess characteristics of circadian rhythms" or "To assess circadian phenotypes"

L123 periodogram is misspelled.

L137 power of the rhythm

L138-139 this description was confusing. It made it sound like they were only considering one (presumably latitude), but in fact they considered each of them in separate analyses.

L218 "if without human cleaning" doesn't make any sense. I kind of understand that humans cleaning out the pests would disrupt the colonization/selection/evolution, but that's not explained.

L236 I might misunderstand, but wouldn't lack of isolation suggest higher gene flow?

L242 suggest "is not occurring on the spatial scale that we examined"

L246 significantly smaller than what? I think the authors just mean significant p values.

L253 I don't know what the authors mean by different phenotypic phenomena than other insect species.

Table 1 was misaligned in my version.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2021 Jan 14;16(1):e0245115. doi: 10.1371/journal.pone.0245115.r002

Author response to Decision Letter 0

20 Nov 2020

11th November 2020

Dear Dr. Henrik Oster (Editor),

Thank you for allowing us to revise and so much for your many useful suggestions for our paper “PONE-D-20-27518, Amplitude of circadian rhythms becomes weaker in the north, but there is no cline in the period of rhythm in a beetle”, and for the two expert reviews. We have revised the manuscript as per the referee requests and hope the revised version is now suitable for publication in '' PLOS ONE”. We have addressed all of the reviewer’s comments – see our responses below.

The author responses to the reviewer’s comments are as follows. Each reviewer’s comment is highlighted in bold, and our responses follow immediately below.

Many thanks,

Takahisa Miyatake

On behalf of all authors

Editors comments:

==============================

We have added to our consideration of your point and discussed these as you requested (Lines 190-211).

Fix issues with the Methods as indicated by reviewer 2.

Author responses: We have fixed the issue raised from reviewer 2, described below.

Discuss the Helfrich-Foerster and Costa studies on weaker fly circadian rhythms in northern latitudes mentioned by reviewer 1.

Author responses: Thank you for your teaching the two important papers which show opposite results from our study. We have cited these, and discussed with these studies (Lines 66-75 and190-198).　

Consider adding phase shift response data.

Author responses: Thank you for your suggestion. We would have liked to do this if we could, but many of the samples we had already collected had been discarded and we were unable to conduct this experiment.　Also, we are currently using the measurement equipment for other projects and are sorry, but we are not in a position to conduct the experiments that the editor pointed out. Instead, we added the phrase “Furthermore, future experiments with phase-shifted experiments will provide a more detailed understanding of the relationship between circadian rhythms and latitude” at the last of Discussion (Lines 283-285).

Discuss (small) effect sizes.

Author responses: Added the discussion for small effect size in lines 269-278, and we have also added “Adjusted R-squared”, an index to show the effect size in the revised manuscript.

Since there was a weak negative correlation between activity and power of rhythm (Spearman’s correlation coefficient = -0.22), lower activities do not necessarily cause lower rhythm.

Moreover, we conducted path analysis to detect the direct and indirect effects. We found the significant direct effect of latitude on power of rhythm and the similar estimated regression coefficient (-1.84 +- 0.76(SE)) to the one reported in the main text (-2.35 +- 1.08(SE)) although there was the significant indirect effect (latitude -> activity -> power of rhythm).

Therefore, we concluded that higher latitude caused lower rhythm although the effect size was small. Likewise, the result of the period was qualitatively same with the one in the main text.

==============================

'Response to Reviewers'

Dear reviewers; Thank you for allowing us to revise and so much for your many useful suggestions for our paper “PONE-D-20-27518, Amplitude of circadian rhythms becomes weaker in the north, but there is no cline in the period of rhythm in a beetle”. We have revised the manuscript as per the referee requests and hope the revised version is now suitable for publication in '' PLOS ONE”. We have addressed all of the reviewer’s comments – see our responses below. The author responses to the reviewer’s comments are as follows. Each reviewer’s comment is highlighted in bold, and our responses follow immediately below.

5. Review Comments to the Author

Author responses: Thank you for highlighting that our manuscript has potential and for your interesting thoughts on our manuscript. We have followed your suggestions and revised the manuscript following your recommendations. We are appreciate it for your teaching the two important papers which show similar results from our study. We altered the phrase (Lines 69-75) with the references (Lines 376-382).　

Discuss the Helfrich-Foerster and Costa studies on weaker fly circadian rhythms in northern latitudes mentioned by reviewer 1.

Author responses: Thank you for your teaching the two important papers which show opposite results from our study. We have cited these, and discussed with these studies (Lines 185-211).

Consequently it would have been nice if the study had also included a phase shift response to light as that would have been perhaps more relevant at these latitudes. Nevertheless, this study comes out in favour of the latter hypothesis. The results reflect a lot of work and the ms is clear to read and understand.

Author responses: Thank you for your useful suggestion. Unfortunately, we are sorry to inform you that it is not possible to conduct this experiment with these wild beetle strains because most of these local populations are not currently being kept in captivity. We're sorry we can't fix it here, but we're very glad you found this study interesting.

My one quibble is that the effects are tiny and require a huge N to be observed. Also the variation in latitude is only 8oC which doesn't help to dissect out an effect. Furthermore the power statistic used is not very sophisticated and there are better methods available, but I suspect the result would be the same.

Author responses: Thank you for your suggestion. We can't come up with a better way to improve on the status quo, and we think that using other methods would not change the results as you suggested, so we didn't alter this point. Instead, in lines 269-278, we added a discussion of the too large sample size and weak detection effect in this analysis.

The Discussion is a bit too long considering the brevity and conciseness of the results, so perhaps a little less speculation would be in order. Otherwise, the study is OK.

Author responses: We have reduced the amount of consideration according to your and another reviewer's points. Also we removed some phrase to short the discussion of the revised manuscript.

We hope the revised version of the manuscript is suitable for publishing.

Thank you for highlighting that our manuscript has potential and for your interesting thoughts on our manuscript. We have followed your suggestions and revised the manuscript following your recommendations.

Author responses: Thank you for your suggestions. “Altitude” in L.26 is my writing miss, and thus I changed it to “longitude”, instead of “altitude”. Sorry for “effects of temperature is also my miss writing, and thus we removed “temperatures” and then altered it to “To analyze the effects if latitude and sex on the period and power of…”. (L 138-139).

Author responses: We changed the wording that is taken to be geographic distribution to latitude, and we've added a couple of recent papers to the list (Lines 66-75).

Author responses: Added the context in discussion as you requested (Lines 190-211).

Author responses: Sorry for the confusion caused by our writing style. The sample size of Table S1 shows individual numbers measured for circadian rhythm. Therefore, the number of individuals with measured circadian rhythms is really very, very large. Therefore, we added the phrase “We measured the circadian rhythms of 17 to 128 individual beetles for a single population”, in lines 116-118, and we placed the following phrase “The sample size measured for circadian rhythm of each population is shown in Table S1”, just after the previous sentence.

Author responses: At a time, we monitored 128 individuals; each animal was put it in each Petri dish. We have prepared 128 locomotor activity sensors. Thus we added the phrase “At a time, we monitored 128 individuals, meaning we are measuring 128 sensors at the same time”, in Lines 123-124.

Author responses: Thank you for your helpful comments. We have improved the sentence about the relationship (Lines145-146).

Since there was a weak negative correlation between activity and power of rhythm (Spearman’s correlation coefficient = -0.22), lower activities do not necessarily cause lower rhythm.

Therefore, we concluded that higher latitude caused lower rhythm although the effect size was small. Likewise, the result of the period was qualitatively same with the one in the main text.

Altered the phrase to “The results of the regression analysis showed that total activity was associated positively with latitude and sex (Table 1, Figure 4).”

7. L158 this statement is really vague. Are the authors talking about clines or just inter-individual variation? What are they trying to say?

Author responses: Removed it.

8. L166-167 The transition to this sentence is really rough. "On the other hand" would usually indicate a contrast with the previous statement, which isn't the case here.

Author responses: Removed it.

Author responses: We combined the two phrases, as you requested.

Author responses: We've put together a short series of these sentences as you requested, and removed the sentence from Semeao's study, which appears a second time, to avoid sentence duplication, as you requested (Lines 240-242).

Author responses: Altered the last phrase as you requested.

Minor

L51 "indicators of circadian rhythms" is vague. These are characteristics of rhythms, and variations in these characteristics could indicate adaptation etc.

Author responses: Altered as you requested (Lines　50-51).

Author responses: Altered as you requested (Lines　54).

L58-59 a positive relationship between "latitude and circadian rhythm" doesn't make sense. I think the authors might mean a positive relationship between latitude and period.

Author responses: Altered as you requested (Lines 57-58).

L75 The syntax is hard to follow. I suggest "This species is found throughout most of Japan, except for the northern island of Hokkaido, meaning..."

Author responses: Changed it as you requested (Lines 81-83).

L89-91 Please write the coordinates in a more standard way.

Author responses: Rewrote (Lines 95 and 96).

L101-103 These two sentences almost completely repeat each other.

Author responses: Removed the latter sentence (see Lines 106-107).

L106 "To assess circadian rhythmicity" or "To assess characteristics of circadian rhythms" or "To assess circadian phenotypes"

Author responses: Changed to “"To assess circadian rhythmicity" (Line 110).

L123 periodogram is misspelled.

Author responses: I think “periodogram” is not misspelled. Instead, altered from “periodgram” to “periodogram” in Lines 129 and 131.

L137 power of the rhythm

Author responses: Altered as you requested (Line 139).

L138-139 this description was confusing. It made it sound like they were only considering one (presumably latitude), but in fact they considered each of them in separate analyses.

Author responses: Explained precisely more for this point (Lines 138-139).

L218 "if without human cleaning" doesn't make any sense. I kind of understand that humans cleaning out the pests would disrupt the colonization/selection/evolution, but that's not explained.

Author responses: Thank you for your suggestion, and thus we altered the phrase to “including human cleaning which may affect to colonization, selection and evolution of creatures in each mill” (Lines 240-242).

L236 I might misunderstand, but wouldn't lack of isolation suggest higher gene flow?

Author responses: There was an error in our original manuscript. We altered it as the correct description “the isolation at each mill suggested lower levels of gene flow…” (Lines 258-259).

L242 suggest "is not occurring on the spatial scale that we examined"

Author responses: Changed as you requested (Lines 264-265).

L246 significantly smaller than what? I think the authors just mean significant p values.

Author responses: Altered the phrase to “Notably, the results of the present study showed P-values smaller than 0.05, even for small effect sizes, due to the very large sample size” in Lines 269-270.

L253 I don't know what the authors mean by different phenotypic phenomena than other insect species.

Author responses: Removed it.

Table 1 was misaligned in my version.

Author responses: Rewrote Table 1, and added “Adjusted R-squared”, an index to show the effect size as the editor requested.

Thank you for your useful comments, and we hope the revised manuscript is suitable for publication.

With best wishes,

Takahisa Miyatake

On behalf of all authors

Attachment

Submitted filename: Responses to Reviewers 20201112.docx

Click here for additional data file.^{(25KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0245115.r003

Decision Letter 1

Henrik Oster

1 Dec 2020

PONE-D-20-27518R1

Amplitude of circadian rhythms becomes weaker in the north, but there is no cline in the period of rhythm in a beetle

PLOS ONE

Dear Dr. Miyatake,

==============================

Please fix all minor issues raised by the reviewers.

Further, it is highly recommended to get support from a native speaker or a professional editing service to improve the English of the manuscript.

==============================

Please submit your revised manuscript by Jan 15 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

We look forward to receiving your revised manuscript.

Kind regards,

Henrik Oster, Ph.D.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

Reviewer #1: No

Reviewer #2: No

**********

6. Review Comments to the Author

Reviewer #1: The ms is interesting but the English really needs to be improved before publication so some editorial assistance is required. Also the organisation of the Discussion could be better. Here are a few further comments.

L66-68. Incorrect statement. The long TIM isoform, not the short one, is negatively correlated with latitude ie higher frequency at lower latitudes.

L203-205 Again the timeless statement is not correct.

‘The frequency of a clock gene ( timeless ) of D. melanogaster studied from 40 to 65 degrees in latitude was negatively phased with latitude, but in populations col lected in southern

Europe by other years , this negative trend seemed to be unclear [21] .’

If the author wishes to use the timeless story, which I think has an important relevant message for this ms. which the authors do touch upon in their discussion of local adaptations and bottlenecks later on, perhaps they might use the paragraph below. I suggest the timeless part be moved to the latter part of the discussion.

‘The frequency of the timeless allele encoding a long TIM isoform of D. melanogaster initially studied from 40 to 65oN was initially negatively correlated with latitude, but in populations collected in extreme southern Europe (32-35oN) this trend was reversed [21] . It turned out that the latitudinal cline was actually caused by natural selection spreading the recently derived tim allele in all directions from a point of origin in southern Italy, thereby generating a distance rather than a latitudinal cline. This ‘distance cline’ was confirmed by studying the tim allele in the Iberian Peninsula (reference Zonato et al 2018 PMID: 29183263) where the cline was reversed. These studies reveal that the history of the genes that encode clinal characteristics also need to be considered when attempting to interpret spatial distributions. Such historical perspectives may account for some of the contradictory results that have been generated in the geographical analyses of biological rhythm phenotypes.

L221 the power of a rhythm is not necessarily the amplitude. It is the general sinusoidal shape of the rhythm. Thus a very sinusoidal but low amplitude rhythms could still have considerable power.

L229 ‘rear flying’????? explain

L291-293. Suggest ‘ Furthermore, given the seasonal differences in light exposure at different latitudes, studying the phase shift of the locomotor rhythm to brief light pulses might also provide a relevant phenotype that might discriminate between northern and southern population, as was the case for Drosophila timeless variants (21)

Reviewer #2: L25 missing word "these traits are" (?)

L55-59 It takes a little "mental gymnastics" for a reader to compare a trend in "higher latitudes" with "a positive relationship with latitude". I suggest adding something to indicate that the two studies are showing trends in the same direction. Like "Similarly, a positive relationship..."

L66 I'm not quite sure what is meant by "frequency of a clock gene". I think the authors mean something like period/frequency of expression. Also not quite sure what is meant by "negatively phased" (negatively correlated?)

L69 I'm not really sure what's meant by "The other context of circadian rhythm". It's not really clear how this is really different from the previous paragraphs where the authors were also talking about relationships with latitude and rhythms. Seasonal variation is mentioned but not really explained.

L71 pioneering

L74 wording doesn't seem right, and it seems trivial to say that the results will be discussed in the context of the literature. Perhaps eliminate this sentence, especially since the next sentence acknowledges the discrepancies.

L82 The authors know more about this than I do, but I usually see this name written as "Hokkaido" in English. Confirm that the spelling is as desired.

L101 this sentence seems to repeat the sentence starting on L91.

L107 Suggest deleting this sentence as it is essentially repeated in the sentence beginning on L109. The sentence beginning on L109 seems better because the association with grain is the part most similar to natural conditions. The temperature and photoperiod presumably vary among sites.

L152-154 I don't understand what the authors are saying here. If you are trying to analyze the relationship between two things (geographical area and power) you need to include them in the same model (?) I think they perhaps mean that effects of latitude and sex were analyzed separately? Or maybe they mean 3 things: latitude, longitude and sex?

L198-199 this is misleading sounds like it spans a range of 32 degrees. Suggest something like "in a range of approximately 8 degrees latitude (from about 32 to 41°N).

L199 Since the authors make it a point that there are no effects of longitude, the longitudinal range (about 10 degrees) should also be given.

L199 The authors say "Previous studies have often" but only cite one study. Preferably cite several examples or refer to the reference in a different way like "(e.g., [21])" (to indicate that it is an example) or ([21] and references therein) if you are citing the reference as a sort of review.

L203 see my comments about similar text within the introduction

L206 what does "this negative trend seemed to be unclear" mean? A negative trend wasn't observed? Or maybe not significant?

L207 it is possible that a cline could be detected

L211 I don't really understand what the authors mean by "survey with closely related species". Do they mean extend the geographic range by pooling results from two species? This idea is unclear.

L211 "In examining the clock cline between different species" is awkward wording. Maybe "In comparing clock clines among speices"

L225-227 wording unclear...kind of repeats "suggest that this beetle disperses very well [35] suggested very high levels of active dispersal" (??) I think the second part of the sentence is meant to be an example. Maybe authors mean "....very well, e.g., Ridley et al. [35] inferred very high levels of active dispersal..."

L229 I don't know what "including rear flying" means

L232; as follows

L248 I'm not sure what the authors mean by ideal environment. I think they mean "ideal" for large effects of bottlenecks and local adaptation. It's not written clearly.

L272 suggest "a cline in circadian amplitude"

L277-279 and L282-286 These two sentences say the same thing. Can they be consolidated?

L288 This line doesn't make sense.

L469 indicate threshold (p-value) for significance.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

PLoS One. 2021 Jan 14;16(1):e0245115. doi: 10.1371/journal.pone.0245115.r004

Author response to Decision Letter 1

18 Dec 2020

The author responses to the reviewer’s comments are as follows. Each reviewer’s comment is highlighted in bold, and our responses follow immediately below.

==============================

Please fix all minor issues raised by the reviewers.

� We fixed all issued raised by the reviewers.

Further, it is highly recommended to get support from a native speaker or a professional editing service to improve the English of the manuscript.

� The English of the re-revised manuscript has been checked by a professional native English editing service.

==============================

6. Review Comments to the Author

� We are glad that you are interested in this paper. The English of the re-revised manuscript has been checked by a professional native English editing service.

L66-68. Incorrect statement. The long TIM isoform, not the short one, is negatively correlated with latitude ie higher frequency at lower latitudes.

� Sorry for our mistake. We corrected it as you requested (Lines 66-69).

L203-205 Again the timeless statement is not correct.

‘The frequency of a clock gene ( timeless ) of D. melanogaster studied from 40 to 65 degrees in latitude was negatively phased with latitude, but in populations col lected in southern

Europe by other years , this negative trend seemed to be unclear [21] .’

‘The frequency of the timeless allele encoding a long TIM isoform of D. melanogaster initially studied from 40 to 65oN was initially negatively correlated with latitude, but in populations collected in extreme southern Europe (32-35oN) this trend was reversed [21]. It turned out that the latitudinal cline was actually caused by natural selection spreading the recently derived tim allele in all directions from a point of origin in southern Italy, thereby generating a distance rather than a latitudinal cline. This ‘distance cline’ was confirmed by studying the tim allele in the Iberian Peninsula (reference Zonato et al 2018 PMID: 29183263) where the cline was reversed. These studies reveal that the history of the genes that encode clinal characteristics also need to be considered when attempting to interpret spatial distributions. Such historical perspectives may account for some of the contradictory results that have been generated in the geographical analyses of biological rhythm phenotypes.

� Sorry for our mistake, again. We rephrased and moved it to the later part of the discussion as you requested (Lines 291-303) and added the reference (Lines 468-471).

L221 the power of a rhythm is not necessarily the amplitude. It is the general sinusoidal shape of the rhythm. Thus a very sinusoidal but low amplitude rhythms could still have considerable power.

� Removed “power” (Line 217)

L229 ‘rear flying’????? explain

� Reword it as “short-range flying” (Line 225)

� Thank you so much for your suggestion for the last phrase. We rephrased it as you requested (Lines 285-289).

Reviewer #2: L25 missing word "these traits are" (?)

� Added “are” (Line 25).

� Added “Similarly,“ (Line 57).

� Altered to “The frequency of the timeless allele encoding a long TIM isoform,” (Lines 66-67), and to “negatively correlated” (Line 68-69), as you requested. Thank you for your suggestions.

� We removed the phrase (Line 69).

L71 pioneering

� Re-worded (Line 70).

� Eliminated the sentence (Lines 73-74).

L82 The authors know more about this than I do, but I usually see this name written as "Hokkaido" in English. Confirm that the spelling is as desired.

� You are quite right. (Line 81).

L101 this sentence seems to repeat the sentence starting on L91.

� Removed the sentence (see Line 100).

� Removed the sentence (see Line 106).

� Sorry to confuse you. The two things were latitude and longitude. Therefore, we rewrote this phrase as “To avoid multicollinearity between latitude and longitude (the correlation coefficient (r) between them was 0.83), we didn’t include both simultaneously in the model as an explanatory variable but constructed a separate model with each value.” (Lines 149-152).

L198-199 this is misleading sounds like it spans a range of 32 degrees. Suggest something like "in a range of approximately 8 degrees latitude (from about 32 to 41°N).

� Altered it as you suggested (Lines 196-197). Thank you.

L199 Since the authors make it a point that there are no effects of longitude, the longitudinal range (about 10 degrees) should also be given.

� We gave it in Line 201.

� Rephrased it as “([21] and references therein)” (Line 197-198).

L203 see my comments about similar text within the introduction

� Rewrote and moved it to the last of the discussion as you and the reviewer 1 commented (Lines 291-303).

L206 what does "this negative trend seemed to be unclear" mean? A negative trend wasn't observed? Or maybe not significant?

� We have corrected this sentence as noted by reviewer 1. (Lines 197-201).

L207 it is possible that a cline could be detected

� Added “a” (Line 203).

L211 I don't really understand what the authors mean by "survey with closely related species". Do they mean extend the geographic range by pooling results from two species? This idea is unclear.

� We rewrote it as “it may be possible to survey the point if we use a closely related species, such as Tribolium confusum who inhabits also in Hokkaido.” Is this make sense? If not the case, we will remove the phrase at the next revision. (Lines 206-208).

L211 "In examining the clock cline between different species" is awkward wording. Maybe "In comparing clock clines among speices"

� Changed it as you requested. (Line 208).

� Altered as you requested. (Line 221-222).

L229 I don't know what "including rear flying" means

� Altered to “short-range flying” (Line 225).

L232; as follows

� Changed (Line 228).

L248 I'm not sure what the authors mean by ideal environment. I think they mean "ideal" for large effects of bottlenecks and local adaptation. It's not written clearly.

� Reworded (Lines 244-245).

L272 suggest "a cline in circadian amplitude"

� Added “circadian” as you suggested (Line 267).

L277-279 and L282-286 These two sentences say the same thing. Can they be consolidated?

� Thank you for your advice. The two sentences have slightly different meanings and are difficult to concatenate. I hope you understand it (See 274-281).

L288 This line doesn't make sense.

� Reworded it (Line 283).

L469 indicate threshold (p-value) for significance.

� Added p-values in the captions of Figures 2 (p<0.05) and 4 (p<0.01), for lines 482-491, respectively.

Thank you for all of your kind suggestions and advices. Red text, other than where the reviewers have noted, is where a professional native English editing service has made corrections. We hope the revised version of the manuscript is now suitable for publication.

With best wishes,

Takahisa Miyatake

Behalf of all authors

Masato S. Abe, Kentarou Matsumura, Taishi Yoshii

Attachment

Submitted filename: Responses to Reviewers.docx

Click here for additional data file.^{(25.2KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0245115.r005

Decision Letter 2

Henrik Oster

23 Dec 2020

Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle

PONE-D-20-27518R2

Dear Dr. Miyatake,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Henrik Oster, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

n/a

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

Reviewer #1: Yes

**********

6. Review Comments to the Author

Reviewer #1: The ms is much improved although the English still needs some work. L217-218 is redundant so cut. the effects on power are small but significant and fit with other findings on other species. Given the Results section is so short and concise, could the authors not similarly reduce the length of the Discussion which is a little repetitive and overlong and a little rambling.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

PLoS One. doi: 10.1371/journal.pone.0245115.r006

Acceptance letter

Henrik Oster

2 Jan 2021

PONE-D-20-27518R2

Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle

Dear Dr. Miyatake:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Prof. Henrik Oster

Academic Editor

PLOS ONE

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

S1 Table. Collection site of T. castaneum populations with latitude and longitude.

(XLSX)

Click here for additional data file.^{(12KB, xlsx)}

S1 Data

(XLSX)

Click here for additional data file.^{(95.3KB, xlsx)}

Attachment

Submitted filename: Responses to Reviewers 20201112.docx

Click here for additional data file.^{(25KB, docx)}

Attachment

Submitted filename: Responses to Reviewers.docx

Click here for additional data file.^{(25.2KB, docx)}

Data Availability Statement

All relevant data are within the manuscript and its Supporting information files.

[pone.0245115.ref001] 1.Endler JA. Geographic Variation, Speciation, and Clines. Princeton University Press, Princeton, NJ: 7; 1977. [PubMed] [Google Scholar]

[pone.0245115.ref002] 2.Coyne JA, Beecham E. Heritability of two morphological characters within and among natural populations of Drosophila melanogaster. Genetics, 1987; 117: 727–737. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref003] 3.James AC, Azevedo RBR, Partridge L. Genetic and environmental responses to temperature of Drosophila melanogaster from a latitudinal cline. Genetics, 1997; 146: 881–890. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref004] 4.Blackenhorn WU, Fairbairn DJ. Life history adaptation along a latitudinal cline in the water strider Aquarius remigis (Heteroptera: Gerridae). Journal of Evolutionary Biology, 1995; 8: 21–41. 10.1046/j.1420-9101.1995.8010021.x [DOI] [Google Scholar]

[pone.0245115.ref005] 5.Kyriacou CP, Peixoto AA, Sandrelli F, Costa R, Tauber E. Clines in clock genes: fine-tuning circadian rhythms to the environment. Trends in Genetics, 24: 2007, 124–132 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref006] 6.Hut RA, Paulucci S, Dor R, Kyriacou CP, Daan S. Latitudinal clines: an evolutionary view on biological rhythms. 2013; Proceedings of the Royal Society B, 2013; 280: 20130433 10.1098/rspb.2013.0433 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref007] 7.Pittendrigh CS, Takamura T. Latitudinal clines in the properties of a circadian pacemaker. Journal of Biological Rhythms, 1989; 4: 105–123. 10.1177/074873048900400209 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref008] 8.Helfrich-Förster C, Bertolini E, Menegazzi P. Flies as models for circadian clock adaptation to environmental challenges. European Journal of Neuroscience, 2020, 51:166–181. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref009] 9.Saunders DS. Insect Clocks, 3rd edn Elsevier, Amsterdam: 2002. [Google Scholar]

[pone.0245115.ref010] 10.Klarsfeld A, Leloup JC, Rouyer F. Circadian rhythms of locomotor activity in Drosophila. Behavioral Processes, 2003; 6: 161–175. 10.1016/s0376-6357(03)00133-5 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref011] 11.Matsumura K, Abe MS, Sharma MD, Hosken D, Yoshii T, Miyatake T. Genetic variation and phenotypic plasticity in circadian rhythms of an armed beetle, Gnatocerus cornutus (Tenebrionidae). Biological Journal of the Linnean Society, 2020; 130: 34–40. [Google Scholar]

[pone.0245115.ref012] 12.Lankinen P. North-south differences in circadian eclosion rhythm in European populations of Drosophila subobscura. Heredity, 1993; 71: 210–218. [Google Scholar]

[pone.0245115.ref013] 13.Zhang Q, Li H, Li R, R H, Fan C, Chen F, et al. Association of the circadian rhythmic expression of GmCRY1a with a latitudinal cline in photoperiodic flowering of soybean. Proceedings of National Academy of Science, 2008; 105: 21028–21033. 10.1073/pnas.0810585105 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref014] 14.Pivarciova L, Vaneckova H, Provaznik J, Wu BC, Pivarci M, Peckova O, et al. Unexpected geographic variability of the free running period in the Linden bug Pyrrhocoris apterus. Journal of Biological Rhythms, 2016; 31: 568–576. 10.1177/0748730416671213 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref015] 15.Paolucci S, Benetta ED, Salis L, Doležel D, van de Zande L, Beukeboom LW. Latitudinal variation in circadian rhythmicity in Nasonia vitripennis. Behavioral Science, 2019; 9: 115 10.3390/bs9110115 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref016] 16.Greenham K, Lou P, Puzey JR, Kumar G, Arnevik C, Farid H, et al. Geographic variation of plant circadian clock function in natural and agricultural settings. Journal of Biological Rhythms, 2017; 32: 26–34. 10.1177/0748730416679307 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref017] 17.Kyriacou CP. Evolution: fruit fly clocks on the edge. Current Biology, 2017; 27, R227–R230. 10.1016/j.cub.2017.02.017 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref018] 18.Lankinen P. Geographical variation in circadian eclosion rhythm and photoperiodic adult diapause in Drosophila littoralis. Journal of Comparative Physiology A, 1986; 159, 123–142. 10.1177/074873048600100202 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref019] 19.Menegazzi P, Benetta ED, Beauchamp M, Schlichting M, Steffan-Dewenter I, Helfrich-Fõrster C. Adaptation of circadian neuronal network to photoperiod in high-latitude European Drosophilids. Current Biology, 2017; 27: 833–839. 10.1016/j.cub.2017.01.036 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref020] 20.Pittendrigh CS, Kyner WT, Takamura T. The amplitude of circadian oscillations: temperature dependence, latitudinal clines, and the photoperiodic time measurement. Journal of Biological Rhythms, 1991; 6, 299–313. 10.1177/074873049100600402 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref021] 21.Tauber E, Zodan M, Sandrelli F, Pegararo M, Osterwalder N, Breda C, et al. Natural selection favors a newly derived timeless allele in Drosophila melanogaster. Science, 2007; 316: 1895–1898. 10.1126/science.1138412 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref022] 22.Champ BR, Dyte CE. Report of the FAO global survey of pesticide susceptibility of stored grain pests. In: FAO Plant Production and Protection Series, Food and Agriculture Organization of the United Nations, Rome.1976; 297 pp.

[pone.0245115.ref023] 23.Sokoloff A. The Biology of Tribolium: v. 2: With Special Emphasis on Genetic Aspects. Oxford University Press, Oxford: 1975. [Google Scholar]

[pone.0245115.ref024] 24.Fedina TY, Lewis SM. An integrative view of sexual selection in Tribolium flour beetles. Biological Reviews, 2008; 83: 151–171. 10.1111/j.1469-185X.2008.00037.x [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref025] 25.Tribolium Genome Sequencing Consortium. The genome of the model beetle and pest Tribolium castaneum. Nature, 2008; 452: 949–955. 10.1038/nature06784 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref026] 26.Matsumura K, Miyatake T. Is there a genetic correlation between movement and immobility in field populations of a beetle? bioRxiv, 10.1101/2020.08.10.245431 [DOI] [Google Scholar]

[pone.0245115.ref027] 27.Sokolove PG, Bushell WN. The chi square periodogram: its utility for analysis of circadian rhythms. Journal of Theoretical Biology, 1978; 72: 131–160. 10.1016/0022-5193(78)90022-x [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref028] 28.Halberg F. Chronobiology. Annual Review of Physiology, 1969; 31: 675–726. 10.1146/annurev.ph.31.030169.003331 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref029] 29.R Development Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. R version 3.4.3. 2017.

[pone.0245115.ref030] 30.Fleury F, Allemand R, Fouillet P, Boulétreau M. Genetic variation in locomotor activity rhythm among populations of Leptopilina heterotoma (Hymenoptera: Eucoilidae), a larval parasitoid of Drosophila species. Behavior Genetics, 1995; 25: 81–89. 10.1007/BF02197245 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref031] 31.Joshi DS. Latitudinal variation in locomotor activity rhythm in adult Drosophila ananassae. Canadian Journal of Zoology, 1999; 77: 865–870. 10.1139/z99-051 [DOI] [Google Scholar]

[pone.0245115.ref032] 32.Block G, Barnes BM, Gerkema MP, Helm B. Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value. Proceedings of the Royal Society B, 2013; 280: 20130019 10.1098/rspb.2013.0019 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref033] 33.Bertolini E, Schbert FK, Zanini D, Sehadová H, Helfrich-Fõrster C, Menegazzi P. Life at high latitudes does not require circadian behavioral rhythmicity under constant darkness. Current Biology, 2019; 29: 3928–3936. 10.1016/j.cub.2019.09.032 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref034] 34.Ridley AW, Hereward JP, Daglish GJ, Raghu S, Collins PJ, Walter GH. The spatiotemporal dynamics of Tribolium castaneum (Herbst): adult flight and gene flow. Molecular Ecology, 2011; 20: 1635–1646. 10.1111/j.1365-294X.2011.05049.x [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref035] 35.Drury DW, Whitesell ME, Wade MJ. The effects of temperature, relative humidity, light, and resource quality on flight initiation in the red flour beetle, Tribolium castaneum. Entomological Experimental and Application, 2016; 15: 269–274. 10.1111/eea.12401 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref036] 36.Arnold PA, Cassey P, White CR. Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate. Functional Ecology, 2017; 31: 653–661. 10.1111/1365-2435.12772 [DOI] [Google Scholar]

[pone.0245115.ref037] 37.Semeao AA, Campbell JF, Beeman RW, Lorenzen MD, Whiteworth RJ, Sloderbeck PE. Genetic structure of Tribolium castaneum (Coleoptera: Tenebrionidae) populations in mills. Environmental Entomology, 2012; 41: 188–199. 10.1603/EN11207 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref038] 38.Konishi K, Matsumura K, Sakuno W, Miyatake T. Death feigning as an adaptive anti-predator behavior: further evidence for its evolution from artificial selection and natural populations. Journal of Evolutionary Biology, 2020; 33: 1120–1128. 10.1111/jeb.13641 [DOI] [PubMed] [Google Scholar]

[pone.0245115.ref039] 39.Matsumura K, Miyatake T. Differences in attack avoidance and mating success between strains artificially selected for dispersal distance in Tribolium castaneum. PLoS ONE, 2015; 10: e0127042 10.1371/journal.pone.0127042 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0245115.ref040] 40.Matsumura K, Archer CR, Hosken DJ, & Miyataka T. Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off. Behavioral Ecology, 2019; 30: 1522–1529. [Google Scholar]

[pone.0245115.ref041] 41.Zonato V, Vanin S, Costa R, Tauber E, Kyriacou CP. Inverse European latitudinal cline at the timeless locus of Drosophila melanogaster reveals selection on a clock gene: population genetics of ls-tim. Journal of Biological Rhythms, 2018; 33: 15–23. 10.1177/0748730417742309 [DOI] [PubMed] [Google Scholar]

PERMALINK

Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle

Masato S Abe

Kentarou Matsumura

Taishi Yoshii

Takahisa Miyatake

Roles

Abstract

Introduction

Materials and methods

Insects

Fig 1. Collection locations of wild T. castaneum populations in Japan.

Ethical note

Locomotor activity

Statistical analysis

Results

Table 1. Statistical test results.

Fig 2. Relationship between the power of the rhythm and latitude (A) or longitude (B).

Fig 3. Relationship between the period of the rhythm and latitude (A) or longitude (B).

Fig 4. Relationship between total activity and latitude (A) or longitude (B).

Discussion

Supporting information

Acknowledgments

Data Availability

Funding Statement

References

Decision Letter 0

Henrik Oster

Roles

Author response to Decision Letter 0

Decision Letter 1

Henrik Oster

Roles

Author response to Decision Letter 1

Decision Letter 2

Henrik Oster

Roles

Acceptance letter

Henrik Oster

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

Similar articles

Cited by other articles

Links to NCBI Databases