Compensating from a bad start in life: linking male energy reserves to reproductive output in a polyphagous moth

Reproduction is known to be energetically and physiologically costly. Consequently, individuals in good condition are assumed to invest substantial resources in reproduction, while those in poor condition are unable to do so. This is particularly relevant in insects, where reproduction is a nutrient-limited process for males and females and is largely related to their energy reserves. Lepidopteran phytophagous insects are an ideal model to evaluate how larval nutrition affects adult reproductive strategies, because larval host plant is considered a key determinant of the adult phenotype and the performance of both males and females. We studied a capital breeder moth species, the European grapevine moth (Lobesia botrana), to investigate how male energy reserves, body condition and reproductive traits might influence female reproductive output, using different host plants as a means of obtaining different male quality. We found that the host cultivar for the larvae strongly influenced the energy reserves of male adult moths, affecting their body condition and ultimately their reproductive potential through the content of spermatophores they transfer to females at mating. Moreover, males having different levels of energy reserves may alter the allocation of energy between their body condition and spermatophore size and composition, supporting the idea that organisms can buffer the effect of nutritional constraints by changing allocation to different fitness-related traits. Females also seem to be able to adjust latency to oviposition accordingly. These results have important implications for understanding the population dynamics of this moth species.