Sex pheromone biosynthesis, storage and release in a female moth: making a little go a long way

Stephen P Foster; Karin G Anderson

doi:10.1098/rspb.2020.2775

. 2020 Dec 16;287(1941):20202775. doi: 10.1098/rspb.2020.2775

Sex pheromone biosynthesis, storage and release in a female moth: making a little go a long way

Stephen P Foster ^1,^✉, Karin G Anderson ¹

PMCID: PMC7779519 PMID: 33323090

Abstract

Moth pheromone research has pioneered much of our understanding of long-distance chemical communication. Two important characteristics of this communication have, however, remained largely unaddressed: the release of small quantities of pheromone by most moth species, despite potential advantages of releasing greater amounts, and the intermittency of release in some species, limiting the time of mate attraction. We addressed the proximate mechanisms underlying these characteristics by manipulating biosynthesis, storage and release of pheromone in females of the noctuid moth Chloridea virescens. We found that (i) mass release is determined by pheromone mass on the gland surface; (ii) amounts synthesized are limited by pheromone biosynthesis activating neuropeptide concentration, not precursor availability; (iii) some gland structural feature limits mass release rate; (iv) intermittent calling enables release at a mass rate greater than biosynthetic rate; and (v) at typical mass release rates, the periodicity of pheromone availability on the gland surface roughly matches the periodicity (intermittency) of calling. We conclude that mass release in C. virescens and possibly many other species is low because of constraints on biosynthesis, storage and gland structure. Further, it appears the behaviour of intermittent calling in C. virescens may have evolved as a co-adaptation with pheromone availability, allowing females to release pheromone intermittently at higher mass rates than the biosynthesis rate.

Keywords: lepidoptera, Chloridea virescens, pheromone synthesis, calling behaviour, pheromone periodicity, chemical signalling

1. Introduction

Animals need effective communication systems for locating mates over distance [1]. A classic example is the use of sex pheromones by many species of moths. Research on these systems has pioneered much of our understanding of the physiological and behavioural mechanisms involved in insect olfaction [2]. Moth pheromone systems are highly stereotypical structurally and functionally [3]. Typically, females produce and release pheromone from an exocrine gland on the intersegmental membrane between the eighth and ninth abdominal segments [4], and males respond to it by flying upwind [5]. Moth pheromones are highly effective in terms of specificity (i.e. ability to attract only conspecific males) and mate location, with males navigating precisely to locate a female over many metres [5].

Although highly effective, two features of these systems seem counterintuitive to efficacy. First, females of most species release relatively small quantities of pheromone (mass release rate; MRR), typically ng min⁻¹ or less [6–10]. Not only are low-intensity chemical signals more prone to interference by noise [11], but higher MRRs increase communication distance and the certainty of attracting a mate [12–14]. How then do females of most species have relatively low MRRs, especially as they have large reserves of metabolites for making pheromone precursor, acetyl CoA [15]? The other counterintuitive feature is variability in release periodicity. Females release pheromone (call) by extruding the ovipositor, thus exposing the gland [14]. Calling generally occurs over an extended (i.e. sexually active) period, coinciding with pheromone biosynthesis and male responsiveness [16,17]. Many species call continuously through the sexually active period [14], thus maximizing mate attraction. However, some species call intermittently (e.g. [18–21]). While reducing time calling should decrease the chance of attracting a mate, it has been speculated that it might allow females to release pheromone at higher MRRs, thus increasing mate attraction [14]. This has yet to be demonstrated.

Both features suggest pheromone quantity in moths may be limited, either by availability (rate of synthesis and/or storage capacity) or some gland property influencing MRR. However, we know little about the proximate mechanisms underlying insect exocrine gland function [22], especially what governs quantity produced and stored and what influences MRR [10]. We are studying pheromone gland function in the moth Chloridea (formerly Heliothis) virescens (Fabricius) (family Noctuidae) [23]. Females synthesize pheromone throughout the scotophase [23,24] and store it predominantly on the gland cuticular surface. Pheromone is then released during calling or catabolized during non-calling [21,23,25]. Young (1 d) females call intermittently through the entire scotophase: on average, around 21 times during an 8 h scotophase, in short (mean 8.3 min) duration bouts with a longer intermittency (mean. 14.6 min) between bouts [21] (i.e. females call for only approx. 36% of the sexually active period).

We decided to test whether limits on pheromone availability or some gland property might explain the small quantities of pheromone released by female C. virescens and other moths. Since C. virescens call intermittently, we also decided to test whether this allowed them to release pheromone at higher MRRs than if they were to call continuously. We addressed three questions concerning pheromone release: (i) what determines MRR? (ii) Is MRR limited and, if so, by what? (iii) Do the dynamics of pheromone availability explain intermittent calling periodicity? We found that females are limited to low MRRs because of a combination of gland surface structure, biosynthesis rate and storage capacity. Further, at a typical MRR, pheromone availability matched periodicity of (intermittent) calling, suggesting that these are co-adapted for effective mate attraction.

2. Methods and materials

(a). Insects and sampling

Insects were maintained at NDSU, Department of Entomology. The colony originated from the USDA-ARS, Fargo and was later supplemented by insects from Dr Fred Gould (North Carolina State University). Larvae were fed a casein-wheatgerm diet [26] and reared at 25°C under a 16 : 8 (L : D) photoperiod. Virgin females for experiments were collected on the day of emergence and used the following day (nominally 1 d old) during the first half of the scotophase.

Pheromone was sampled by several methods (figure 1). For total gland amount, we dissected the gland, placed it in approximately 20 µl of n-heptane with 50 ng of (E)-11-tetradecenal as internal standard (IS) and left it to extract at ambient temperature for at least 1 h before analysis. For surface pheromone, a vascular clip applied to the abdomen extruded the ovipositor, and the gland was rinsed with approximately 100 µl of n-heptane into a small tube with 50 ng IS [27]. Released pheromone was collected according to the method of [28]. We modified this by forcing gland extrusion with a vascular clip. This yields MRRs comparable to those from freely calling females [21,23] and allows a more controlled and consistent determination of MRR [29]. The extruded gland was placed inside a small funnel (figure 1a), fashioned from the tapered section (max diam. ca. 2 mm) of a Pasteur pipette connected to a 20 cm length of DB1-coated capillary column (530 µm i.d., 5 µm film thickness; Agilent Technologies, Santa Clara, CA). The column was connected to a vacuum pump (KNF Neuberger, Trenton, NJ, model NMS010S) that pulled air (approx. 5 ml min⁻¹). We collected pheromone for either 5 or 15 min, the former gave a more accurate MRR at a given time (averaged over 5 min for detection of pheromone), while the latter allowed sampling for longer periods with fewer changes and analyses of collection columns. After collection, pheromone was eluted, along with 50 ng IS, with approximately 100 µl of n-hexane.

(b). Chemical analysis

Pheromone was analysed by coupled gas chromatography/mass spectrometry (GC/MS; Agilent Technologies 7890/5977B; see electronic supplementary material). For quantification, m/z 192 and 220 were monitored. These are prominent fragments (M-H₂O)⁺ of the IS and major pheromone component, (Z)-11-hexadecenal (Z11-16:Ald), respectively. We quantified the major component only because it constitutes ca. 90% of pheromone mass [30]. For the isotope experiment, we also monitored m/z 222 and 224, the corresponding isotopomers of Z11–16:Ald with one (M + 1) and two (M + 2) ¹³C₂-acetate monomers, respectively.

(c). Experiments

(i). Correlation of surface amount and gland area with initial mass release rate

Females (n = 44) were decapitated at the start of the scotophase and immediately injected with 5 pmole synthetic Helicoverpa zea PBAN (Bachem, Torrance, CA) in 1 µl Hepes saline (187.5 mM NaCl, 4.83 mM KCl, 2.6 mM CaCl₂, 10 mM Hepes, 14 mM glucose, adjusted to pH 6.8). After 1–2 h, a vascular clip was applied to extrude the gland, and pheromone was collected for 5 min, after which the gland was sampled by a solvent rinse. Additionally, we estimated gland surface area by dissecting it on a microscope slide and placing pressure with another slide to flatten it into a crude rectangle. Gland width and length were measured, roughly compensating by eye for deviation from a rectangle. Because the gland was effectively flattened on top of itself (i.e. only half of the gland was visible), the calculated area was doubled to obtain approximate gland surface area.

(ii). Supernormal mass synthesis rate

Previously, we determined a pheromone biosynthesis rate in intact females using mass isotopomer distribution analysis (MIDA) [23,24]. However, this requires that Z11-16:Ald be in a near steady state concentration to calculate fractional and absolute synthetic rates [31,32]. Since a steady state is not reached following injection of a PBAN bolus for at least 2 h (see Results), we modified our approach. At the start of the scotophase, females were fed a 12.5 µl droplet of a 10% solution of U-¹³C-glucose (greater than 98% isotopically enriched; Cambridge Isotope Laboratories, Cambridge, MA) and immediately injected with either 5 pmol of PBAN or saline. Females were then sampled by whole gland extract 30 or 60 min later. Each treatment was replicated using 9–11 females. Precursor enrichment (i.e. the proportion of acetate monomer precursor in the Z11-16:Ald pool derived from the U-¹³C-glucose; see electronic supplementary material) was calculated for each female, allowing us to predict intensities of all nine Z11-16:Ald isotopomers using the recorded (M + 2) isotopomer and allowing for spectral overlap from (M + 0) and (M + 1) isotopomers. Isotopomers were summed to calculate the amount of ‘labelled’ pheromone (synthesized after ingestion of U-¹³C-glucose). Unlabelled pheromone (synthesized prior to ingestion of U-¹³C-glucose) was calculated by subtracting the predicted (M + 0) isotopomer intensity for labelled pheromone from the recorded (M + 0) isotopomer.

(iii). Effect of continuous pheromone release on surface pheromone quantity and mass release rate

We determined the dynamics of MRR and pheromone surface amount in intact (normal MRR) females, 2–4 h into the scotophase, and females injected with 5 pmole of synthetic PBAN at the start of the scotophase (supernormal MRR). For the latter, after injection of PBAN, females were decapitated and left for 1 h before initial sampling, in order to preclude calling and allow pheromone to increase on the gland surface. At the start of sampling, females had the gland forcibly extruded (vascular clip) and placed in the collection apparatus. For MRR, pheromone was collected from each female (n = 15 for intact, n = 13 for PBAN-injected) every 15 min for 1 h (i.e. 4 samples for each female). It took approximately 30 s to change columns, but this is not accounted for in the nominal period; each collection was a full 15 min. Females (different for each replicate at each time) were also sampled by a solvent rinse at the start (t = 0) and every 15 min thereafter for 1 h. These females also had the gland extruded in the collection apparatus throughout the experiment, but the collected pheromone was not analysed. For each time, 6–11 females were sampled.

(iv). Gland maximum mass release rate

Females were decapitated within 8 h of eclosion and left for 16 h, ensuring they had little pheromone. Then, they were injected with 5 pmole PBAN, left for 5 min and sampled 10, 20, 40, 75 and 120 min later. Glands were forcibly extruded and sampled either by solvent rinse (n = 8–9 for each time) or by collection for 5 min (n = 9–10 for each time). All data for the four experiments are given in the electronic supplementary material.

(d). Estimating periodicity of pheromone refill time

We estimated pheromone refill time after release for comparison with published calling periodicity for 1-day-old females [21]. We used published data on mass synthesis rate [23] along with data from the third experiment and performed a rough ‘back of the envelope’ calculation. During a 480 min sexually active period, a 1 d C. virescens female synthesizes approximately 600 ng of Z11-16:Ald [23], at a mean mass synthesis rate of 1.25 ng min⁻¹. Females start synthesizing pheromone approximately 60 min before the scotophase [23], meaning that they would have an initial amount of 75.0 ng at the scotophase start. We then estimated Z11-16:Ald refill time to the initial level, after a fixed calling bout of 8.3 min (mean observed [21]) for two MRRs: (i) an initial ‘high’ rate of 6.0 ng min⁻¹ (≈ PBAN-injected females in 3^rd experiment), and (ii) an initial ‘normal’ rate of 2.5 ng min⁻¹ (≈ intact females in 3rd experiment). The amount of pheromone released during a bout was determined by integrating the appropriate part (8.3 min duration) of the MRR curves from the third experiment. The surface amount required for the initial MRR was interpolated from data from the third experiment. We also calculated the same parameters assuming females called continuously through the scotophase at a sustainable MRR (≈ mass synthesis rate). For simplicity's sake, we did not account for pheromone catabolism [21,23], although we later discuss its possible modifying effects.

(e). Statistics

All statistical analyses were carried out using JMP [33]. In the first experiment, the collection and rinse samplings were not strictly independent (i.e. the loss of pheromone by collection reduced the amount of surface pheromone), although the amount collected in 5 min was always much less (less than 25%) than the amount remaining. Therefore, we used Spearman ρ tests, which assess rank rather than a linear relationship, for correlations among surface amount, gland area and MRR. In the 2nd and 4th experiments, respectively, we tested differences in amounts of labelled and unlabelled pheromone between two types of female, and in MRR and gland surface amount at different times, by one-way ANOVA, after first confirming normality and heteroscedasticity. Means were compared by Student's t-tests. For the third experiment, the amount released (per 15 min) and surface amount, with respect to time, were fitted using a two parameter (2P) exponential decay model [33]. Rates of decline for the two types of female were compared by analysis of means. For all statistical analyses, α = 0.05.

3. Results

(a). Correlation of surface amount and gland area with initial mass release rate

Within 2 h after PBAN injection, females had very high amounts of Z11-16:Ald on the gland surface (figure 1a). Females also released high amounts of Z11-16:Ald during the 5 min collections, averaging 7.08 ± 0.68 ng min⁻¹. There was a positive correlation (Spearman ρ = 0.70, p < 0.001) between the residual amount of Z11-16:Ald on the gland surface and amount released. By contrast, there was no correlation (Spearman ρ = 0.02, p = 0.91) between release rate and gland surface area (figure 1b), nor between amount of Z11-16:Ald on the gland surface and gland surface area (Spearman ρ = 0.20, p = 0.18).

(b). Supernormal mass synthesis rate

The amount of labelled Z11-16:Ald in females fed U-¹³C-glucose was greater in PBAN-injected, at both 30 and 60 min (ANOVA F_3,35 = 33.59, p < 0.001; Student's t-test), than in saline-injected females (figure 1c). There was nearly four times as much labelled Z11-16:Ald in PBAN-injected, compared to saline-injected, females at 60 min. There was no difference (ANOVA F_3,35 = 2.41, p = 0.08) in the amount of unlabelled Z11-16:Ald among any of the treatments (figure 1c).

(c). Effect of continuous pheromone release on surface pheromone quantity and mass release rate

Both intact and PBAN-injected females had similar exponential declines in Z11-16:Ald released over the 60 min (figure 2a). The rates of decline for both females (−0.055 ± 0.019 for intact and −0.034 ± 0.007 for PBAN-injected) were not different (analysis of means, α = 0.05).

Similarly, both intact and PBAN-injected females showed exponential declines in surface pheromone amount over 60 min (figure 2b). As expected, initial surface amount was much greater (2–3 times) for PBAN-injected than intact females. Again, data for both females fit an exponential 2P model for surface amount (each 15 min), with the rates of decline (−0.033 ± 0.016 for intact and −0.031 ± 0.005 for PBAN-injected) not different (analysis of means, α = 0.05).

(d). Gland maximum mass release rate

The amount of pheromone on the gland surface increased (ANOVA F_4,36 = 9.59, p < 0.001) throughout, reaching 180 ng at 120 min (figure 3a). Importantly, the amount of pheromone on the surface at 120 min was greater (Student's t-test, p < 0.05) than the amount at 45 min. By contrast, MRR (figure 3a) peaked (ANOVA F_4,42 = 9.59, p < 0.001) at 6.9 ng min⁻¹ at 40 min and remained (Student's t-test, p < 0.05) at this rate for the rest of the experiment.

(e). Estimating periodicity of pheromone refill time

With an initial surface amount of 75.0 ng (see Methods) at the start of the scotophase, continuously calling females would have an initial MRR of approximately 2.5 ng min⁻¹ (figure 2) that drops after ca. 35 min to a sustainable 1.25 ng min⁻¹ for the remainder of the scotophase. For a MRR of 6 ng min⁻¹, approximately 200 ng Z11-16:Ald would be required on the gland surface (figure 2), necessitating a further 100 min (at 1.25 ng min⁻¹ biosynthesis rate [23]) without calling. During a calling bout of 8.3 min, a female would release approximately 43 ng Z11-16:Ald, requiring 34 min to refill the gland to 200 ng. Thus, at this high MRR, females would call (8.3 min duration) only approximately 11 times during an 8 h scotophase (figure 3b). For an initial MRR of 2.5 ng min⁻¹, females need approximately 70 ng on the gland surface (figure 2) and could therefore start releasing pheromone at the start of the scotophase. An 8.3 min calling bout would release approximately 17.5 ng Z11–16:Ald, requiring 14 min (intermittency) to refill the gland to 70 ng. Thus, females could call approximately 20.5 times during an 8 h scotophase. The intermittency and calling frequency at this MRR are very similar to the published values (14.5 min and 20.8 times, respectively [21]).

4. Discussion

(a). What determines pheromone mass release rate?

It is typically assumed [6,8], but has rarely been demonstrated [34,35], that gland titre is positively related to MRR (i.e. the greater the titre, the greater MRR). In C. virescens, MRR is determined by pheromone mass on the gland surface. Not only was there a positive correlation between them, but their respective dynamics paralleled each other. This was true for females producing pheromone at normal (intact) and supernormal (PBAN-injected) MRRs. When releasing pheromone, both types of female exhibited exponential declines in surface amount and MRR. An exponential decline in MRR has been noted previously in the moth Trichoplusia ni [36]. This demonstrates that the gland releases pheromone at a rate greater than it synthesizes (replaces) it; over time, calling will result in MRR tending toward the biosynthetic rate.

For C. virescens, the relationship between MRR and surface amount is probably true also for MRR and total gland titre, because females store most pheromone on the gland surface [25,27,37]. However, this may not be true in other species, especially those using alcohols or acetate esters as pheromone components. Aldehydes are synthesized in the gland cuticle by oxidation of alcohol precursors [38]. Thus, pheromone must be stored in or on the cuticle, with the surface offering greater capacity than the minute pores [39] through which pheromone is likely translocated to the surface. By contrast, alcohol and acetate esters are produced wholly within gland cells [40,41]. We do not know where these components are stored but, if in cells, translocation could limit surface amount and MRR [22].

(b). Is pheromone mass release rate limited?

The relationship between the surface amount and MRR broke down at higher quantities. Specifically, under our conditions, MRR had a maximum (mean) of approximately 7 ng min⁻¹ (5 min collections) and reached approximately 40 min after PBAN injection. By contrast, surface pheromone increased past this time, with a possible plateau at least 75 min after PBAN injection. The MRR peak occurred at a surface amount corresponding to approximately 80–100 ng of Z11-16:Ald, an amount commonly observed in females (e.g. [25,27]).

Evaporation rate of a semivolatile chemical is dependent on vapour pressure, temperature, airspeed and surface area [25,27,42]. Since temperature and airspeed were constant in our experiments, this suggests that the effective pheromone surface area maximum was reached at 80–100 ng of Z11-16:Ald. However, we found no relationship between gland area and MRR. Therefore, pheromone might not be distributed over the entire gland surface but restricted to specific sites/structures. Raina et al. [39] noted microdroplets, coinciding with pheromone synthesis, at the tips of cuticular hairs on the gland of Helicoverpa zea and suggested they were neat pheromone. If pheromone were localized to spherical microdroplets, mass could increase substantially without much increase in pheromone surface area.

Injection of synthetic PBAN gave a mass synthesis rate of Z11-16:Ald greater than that in intact females, indicating this rate is not limited by the availability of precursor, but by PBAN concentration. In many moth species, PBAN functions by activating acetyl CoA carboxylase, thus controlling biosynthesis rate [43]. Although a higher biosynthesis rate is feasible, it is worth noting that the actual storage amount is probably limited by concentration-dependent catabolism of pheromone [23]. This is indicated by the apparent plateau in surface amount after 75 min (figure 3a).

(c). Does pheromone availability match calling periodicity?

Pheromone MRR in C. virescens is dynamic, exponentially decreasing over time, due to females releasing pheromone at a MRR greater than biosynthesis rate (figure 3b). Thus, females must cease calling to refill this pool, so that when they call again, they can release at the higher MRR. By calculating pheromone loss and refill time, we showed that, at a typical MRR and calling duration, refill time matched the previously observed behavioural intermittency between calling bouts [21]. By contrast, a higher MRR required a much longer refill time (intermittency), with fewer potential calling bouts of the same duration during a scotophase.

Since a gland produces a fixed amount of pheromone during a sexually active period [23], a moth must tradeoff between a high MRR for a short time and a low MRR for a longer time. Continuously calling species likely have a MRR similar to the biosynthesis rate, presumably because this is sufficient to attract a mate during the length of the sexually active period. However, for species like C. virescens, we assume that an MRR similar to biosynthesis rate is inadequate for attracting mates, perhaps because males are located greater distances away [12,13]. Thus, females have adapted to release pheromone intermittently at a higher MRR. However, a single calling bout must be of sufficient duration to allow a responding male to locate the female or to get sufficiently close so that it can respond when calling resumes.

5. Conclusion

Under fixed environmental conditions, the C. virescens gland has a finite MRR, limited by some gland structural feature as well as biosynthesis rate and storage capacity. Together, these multiple mechanisms likely make pheromone MRR in this species resistant to selection for an increased amount. If true more generally, this could explain the small quantities of pheromone released by most species of moths.

Intermittent calling allows female C. virescens to release pheromone at a MRR greater than the biosynthesis rate. Moreover, the intermittency between, and frequency of, calling bouts during the sexually active period, can be predicted by the pheromone refill time, suggesting that pheromone physiology and behaviour are co-adapted for effective mate attraction.

Supplementary Material

Experimental calculations and data

rspb20202775supp1.pdf^{(159.5KB, pdf)}

Reviewer comments

rspb20202775_review_history.pdf^{(605.3KB, pdf)}

Acknowledgements

We thank Dr Jerome Casas for comments on an earlier version of the manuscript.

Data accessibility

Data are available in the electronic supplementary material.

Authors' contributions

S.P.F. was involved with designing, carrying out and analysing experiments, and wrote the manuscript. K.G.A. was involved with carrying out experiments.

Competing interests

We declare we have no competing interests

Funding

Funding toward the GC/MS system was provided by USDA–NIFA Instrument grant, 2015-07238 and by Cooperative State Research, Education, and Extension Service ND02388

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36.Bjostad LB, Gaston LK, Shorey HH. 1980. Temporal pattern of sex pheromone release by female Trichoplusia ni. J. Insect. Physiol. 26, 493–498. [Google Scholar]
37.Foster SP, Anderson KG. 2020. The effect of pheromone synthesis and gland retraction on translocation and dynamics of pheromone release in the moth Chloridea virescens. J. Chem. Ecol. 46, 581–589. ( 10.1007/s10886-020-01198-y) [DOI] [PubMed] [Google Scholar]
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39.Raina AK, Wergin WP, Murphy CA, Erbe EF. 2000. Structural organization of the sex pheromone gland in Helicoverpa zea in relation to pheromone production and release. Arthr. Struct. Devel. 29, 343–353. ( 10.1016/s1467-8039(01)00014-7) [DOI] [PubMed] [Google Scholar]
40.Hagström ÅK, Walther A, Wendland J, Löfstedt C. 2013. Subcellular localization of the fatty acyl reductase involved in pheromone biosynthesis in the tobacco budworm, Heliothis virescens (Noctuidae: Lepidoptera). Insect Biochem. Mol.r Biol. 43, 510–521. ( 10.1016/j.ibmb.2013.03.006) [DOI] [PubMed] [Google Scholar]
41.Jurenka RA, Roelofs WL. 1989. Characterization of the acetyltransferase used in pheromone biosynthesis in moths: specificity for the Z isomer in Tortricidae. Insect Biochem. 19, 639–644. ( 10.1016/0020-1790(89)90098-x) [DOI] [Google Scholar]
42.Pannunzi M, Nowotny T. 2019. Odor stimuli: not just chemical identity. Front. Physiol. 10, 1428 ( 10.3389/fphys.2019.01428) [DOI] [PMC free article] [PubMed] [Google Scholar]
43.Jurenka R. 2017. Regulation of pheromone biosynthesis in moths. Cur. Opin. Insect Sci. 24(Supplement C), 29–35. ( 10.1016/j.cois.2017.09.002) [DOI] [PubMed] [Google Scholar]

Associated Data

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

Supplementary Materials

Experimental calculations and data

rspb20202775supp1.pdf^{(159.5KB, pdf)}

Reviewer comments

rspb20202775_review_history.pdf^{(605.3KB, pdf)}

Data Availability Statement

Data are available in the electronic supplementary material.

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[RSPB20202775C43] 43.Jurenka R. 2017. Regulation of pheromone biosynthesis in moths. Cur. Opin. Insect Sci. 24(Supplement C), 29–35. ( 10.1016/j.cois.2017.09.002) [DOI] [PubMed] [Google Scholar]

PERMALINK

Sex pheromone biosynthesis, storage and release in a female moth: making a little go a long way

Stephen P Foster

Karin G Anderson

Abstract

1. Introduction

2. Methods and materials

(a). Insects and sampling

Figure 1.

(b). Chemical analysis

(c). Experiments

(i). Correlation of surface amount and gland area with initial mass release rate

(ii). Supernormal mass synthesis rate

(iii). Effect of continuous pheromone release on surface pheromone quantity and mass release rate

(iv). Gland maximum mass release rate

(d). Estimating periodicity of pheromone refill time

(e). Statistics

3. Results

(a). Correlation of surface amount and gland area with initial mass release rate

(b). Supernormal mass synthesis rate

(c). Effect of continuous pheromone release on surface pheromone quantity and mass release rate

Figure 2.

(d). Gland maximum mass release rate

Figure 3.

(e). Estimating periodicity of pheromone refill time

4. Discussion

(a). What determines pheromone mass release rate?

(b). Is pheromone mass release rate limited?

(c). Does pheromone availability match calling periodicity?

5. Conclusion

Supplementary Material

Acknowledgements

Data accessibility

Authors' contributions

Competing interests

Funding

References

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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