Larval food composition affects courtship song and sperm expenditure in a lekking moth

Abstract

1. Variation in larval food composition can have far-reaching effects on the adult phenotype of insects. To maximise reproductive output, it is therefore beneficial if insects are able to plastically adapt to nutritional cues in their larval diet.2. The expression of sexual traits implicated in pre-and postcopulatory sexual selection of the lesser wax moth, Achroia grisella Fabricius, across different rearing environments of varying diet composition was investigated.3. Moths reared on diet with relatively low amounts of carbohydrate, but more protein and fats, had lower survival rates, decreased body mass, and longer development times. Males reared on this diet produced songs with higher pulse pair rates (which are attractive to females) and transferred more sperm per copulation than males reared on the alternative diets.4. There was no evidence for a trade-off between pre-and postcopulatory traits. Interestingly, individuals with both higher pulse pair rates and more transferred sperm came from the treatment group with higher mortality rates and generally poorer development. The present results suggest that both of these sexual characteristics are developmentally plastic, but that only moths reared on the protein-rich diet were able to benefit from this plasticity.

The complex interplay between macronutrient intake, cuticular hydrocarbon expression and mating success in male decorated crickets

“…However, the fact that PC1 and PC3 in our study both peak at a specific P:C ratio demonstrates that it matters what nutrients these calories are coming from. The small angle ( θ = 9.74°) between the linear nutritional vectors, the lack of difference in the nutritional gradients from our sequential model and the similar optimal P:C ratio for PC1 and PC3 (1 : 1.5 and 1 : 1, respectively) indicate that both vectors of CHC expression are maximized at an almost equal intake of P and C. Our work therefore adds to the growing list of studies showing that the balanced intake of specific nutrients are key to the condition‐dependent expression of male sexual traits (Maklakov et al ., ; South et al ., ; Fedina et al ., ; Sentinella et al ., ; Harrison et al ., ; Cordes et al ., ; House et al ., ).…”

Are sexually selected traits affected by a poor environment early in life?

“…[54]). There are, however, far fewer studies that explore the effects of a poor juvenile diet on sperm reserves and sperm replenishment rates (but see: [35, 40]). We found that both sperm reserves and replenishment rates were affected by a male’s early diet in an age-dependent manner.…”

“…[38, 39]). This could shift the relative allocation of resources to sperm competitiveness versus attractive ornaments [40]. For example, greater investment in larger body size or weaponry can result in smaller testes and ejaculates [41, 42].…”

“…[43–45]). Fewer studies, especially of vertebrates, have tested how a restricted juvenile diet affects sperm traits (but see: [35, 40, 46]). Male fertilization success is highly dependent on resource allocation to traits that are under post-copulatory sexual selection, especially when sperm competition is intense [47].…”

The evolution of expenditure on testes

“…For example, the expected negative relation between testes mass and weaponry was convincingly demonstrated in the beetle Onthophagus nigriventris (Simmons & Emlen, ), in the myobatrachid frog Crinia georgiana (Parker et al ., ), and across pinniped species (Fitzpatrick et al ., ), and male bustards Chlamydotis undulata that invest most heavily on extravagant sexual displays to attract mates have accelerated senescence in ejaculate quality and fertility (Preston et al ., ). However, no relationship between RTS and horn size was found across species in the genus Onthophagus , possibly because of evolutionary changes in the developmental mechanisms regulating trait growth (Simmons & Emlen, ), or between the size of horns/antlers and RTS across species within the ungulate order Artiodactyla , (Ferrandiz‐Rovira et al ., ), and no evidence for a trade‐off between pre‐ and post‐copulatory traits was found in male Mongolian gerbils Meriones unguiculatus (Shen et al ., ) or the lesser wax moth Achroia grisella (Cordes et al ., ), a lekking species.…”