Social Experience Affects Same-Sex Pairing Behavior in Male Red Flour Beetles ( Tribolium castaneum Herbst)

Male red flour beetles ( Tribolium castaneum Herbst) often pair and attempt to copulate with other males. We examined whether a male’s previous social experience affected his tendency to pair with other males. Virgin males were kept at different densities (singly, or with 3 or 7 males) and tested after 7, 14, or 28 days. Males performed fewer male-male pairing behaviors after being kept in higher densities and more male-male pairing behaviors after being kept with other males for longer periods of time. We also gave males experience with other males either before or after being isolated and found that male-male pairing behavior was most strongly influenced by a male’s most recent social experience. Finally, we found that being kept with females decreased a male’s subsequent tendency to pair with males relative to those previously kept with males. Overall, the results suggest that the type of social experience males acquire has a clear effect on whether they will pair with males in the future.