Meeting Abstract
52.2 Sunday, Jan. 5 10:15 Genital evolution in bats- a study of glans elaboration ORR, T.J.*; BRENNAN, P.L.R.; UMass Amherst; UMass Amherst tjorr@cns.umass.edu
Genitalia are extraordinarily diverse and likely evolve via several processes, primarily sexual selection. The mechanisms include male-male competition (sperm competition), selection for female stimulation (cryptic female choice) or sexually antagonistic coevolution (conflict between the sexes for control of fertilization). How these processes shape genital evolution when mating system and reproductive physiology vary independently is unclear. Bats present a diverse, generally well-studied speciose group within which to investigate how male genital elaborations might vary in the context not only of sexual selection but also physiology and phylogeny. Amid the assorted ecologies and mating systems of bats are three types of reproductive delays including; delayed fertilization, implantation and development. Delayed fertilization (DF) occurs when females store sperm for extended periods before ovulating. By increasing the time over which fertilization occurs, species with DF may experience increased sperm competition and females may store and select among sperm from multiple mates. Previous studies concluded that baculum morphology is not associated with level of promiscuity, thus we investigated glans elaboration. We expected taxa with DF to have more elaborations to allow locking, sperm removal, sperm transfer or female stimulation. Using Scanning Electron Microscopy we examined the glans penis surface of multiple bat species to determine if the presence of penile spines relates to DF, mating system and/or phylogenetic relationships. Although there are significant phylogenetic relationships in the presence and type of penile spines (e.g., Phyllostomid bats lack spines, Mollossid bats usually have spines) the relationship is complicated by both physiological mode and other biological attributes. We discuss these complications and present the results of this study integrating behavior and physiology to evaluate genital evolution.
