Potential strategic allocation of nuptial gift proteins of the neotropical katydid Conocephalus ictus (Orthoptera Tettigoniidae)

[Display omitted] •We found in the spermatophore of C. ictus 177 different putative proteins.•Spermatophores and the mass of their proteins are independent of the males’ size.•There is a potential trade-off between wing size and protein allocation in males.•The males could transfer their ejaculates according to the females’ quality. In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing large spermatophores can increase female fecundity and lifespan, it may also decrease their sexual receptivity, benefiting male fitness. Allocating resources to these edible gifts may entail a lower apportionment of them to other functions, generating a trade-off between somatic and reproductive functions. Despite their effect on male and female fitness, little is known of the compounds associated with katydid spermatophores. Our study found 177 different putative proteins in the spermatophore of Conocephalus ictus, with no correlation between male body size with spermatophore mass, number, concentration and mass of proteins. However, we did observe a negative relationship between male forewing length and protein concentration, and a negative relationship between the mass of the spermatophore transferred to the females and their body size, suggesting a resource allocation trade-off in males, but also strategic transference of resources based on female quality.