Postcopulatory sexual selection is now widely recognized as a key driver of reproductive trait evolution, including the machinery required to produce endogenous nuptial gifts. Despite the importance of such gifts, molecular composition of the non-gametic components of male ejaculates and their interactions with female reproductive tracts remain poorly understood. .  Here we combined transcriptomic studies of both male and female reproductive glands with proteomic and metabolomic approaches to better understand the synthesis, composition and fate of this spermatophore gift in the common Eastern firefly, Photinus pyralis.