Abstract
Most theoretical models of age-related mate choice predict that females should prefer older males because they have proven survival ability. An alternative view is that older males represent inferior mates because of negative genetic correlations between early and late fitness components, or because older males have traded off longevity against other fitness components, have accumulated deleterious germ-line mutations, or are less well adapted to current conditions than more recently born individuals. While numerous studies have reported female choice for older males, few have explicitly examined the fitness consequences of such a preference. We present evidence from a lekking sandfly, Lutzomyia longipalpis, showing that choosy females discriminate against older males and gain a fitness benefit from their choice. When permitted free choice from an aggregation consisting of males aged zero to two days (young), four to six days (middle-aged) and eight to ten days (old), females preferentially mated with middle-aged males, but all measures of female reproductive success were independent of male age. In contrast, when a second set of females was randomly assigned single virgin males of known age, the eggs of those paired to old mates exhibited lower hatching success than the eggs of females mated to young or middle-aged males. These results suggest that females avoid mating with older males because they represent poorer quality mates. Age-related differences in male quality may have a genetic basis, but could equally well arise through a phenotypic decline in sperm quality or sperm transfer ability with male age. The lack of evidence of female discrimination against older males from other studies may be because these did not explore the reproductive success of the full age range of males.
Full Text
The Full Text of this article is available as a PDF (188.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chaniotis B. N. The biology of California Phlebotomus (Diptera: Psychodidae) under laboratory conditions. J Med Entomol. 1967 May;4(2):221–233. doi: 10.1093/jmedent/4.2.221. [DOI] [PubMed] [Google Scholar]
- Jarvis E. K., Rutledge L. C. Laboratory observations on mating and leklike aggregations in Lutzomyia longipalpis (Diptera: Psychodidae). J Med Entomol. 1992 Mar;29(2):171–177. doi: 10.1093/jmedent/29.2.171. [DOI] [PubMed] [Google Scholar]
- Jones TM, Hamilton JGC. A role for pheromones in mate choice in a lekking sandfly. Anim Behav. 1998 Oct;56(4):891–898. doi: 10.1006/anbe.1998.0857. [DOI] [PubMed] [Google Scholar]
- Killick-Kendrick R., Leaney A. J., Ready P. D. The establishment, maintenance and productivity of a laboratory colony of Lutzomyia longipalpis (Diptera: Psychodidae). J Med Entomol. 1977 Jan 31;13(4-5):429–440. doi: 10.1093/jmedent/13.4-5.429. [DOI] [PubMed] [Google Scholar]
- doi: 10.1098/rspb.1998.0484. [DOI] [PMC free article] [Google Scholar]
- Price D. K., Hansen T. F. How does offspring quality change with age in male Drosophila melanogaster? Behav Genet. 1998 Sep;28(5):395–402. doi: 10.1023/a:1021677804038. [DOI] [PubMed] [Google Scholar]
- Ready P. D. Factors affecting egg production of laboratory-bred Lutzomyia longipalpis (Diptera: Psychodidae). J Med Entomol. 1979 Nov 23;16(5):413–423. doi: 10.1093/jmedent/16.5.413. [DOI] [PubMed] [Google Scholar]
- Tatar M., Promislow D. E., Khazaeli A. A., Curtsinger J. W. Age-specific patterns of genetic variance in Drosophila melanogaster. II. Fecundity and its genetic covariance with age-specific mortality. Genetics. 1996 Jun;143(2):849–858. doi: 10.1093/genetics/143.2.849. [DOI] [PMC free article] [PubMed] [Google Scholar]