ABS 2023
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Alternative reproductive strategies in male eastern carpenter bees
Lyllian A.-J. Corbin, Lyndon B. Duff, Miriam H. Richards. Brock University, St. Catharines, Ontario, Canada

Males of the eastern carpenter bee (Xylocopa virginica), arrive to their nesting site before females (protandry) and hold territories to compete for access to mates. The persistence of these strategies is explained by sexual selection theory; however, males use alternative tactics to avoid direct competition while limiting their access to mates, which is often associated with body size. Using 5 years of observations, we investigated patterns in the phenology and body size of X. virginica males to highlight selective pressures influencing their mating behaviour. Bees were individually measured and marked at several nest aggregations near Brock University, where we recorded daily flight activity. Most males were protandrous and remained at the same aggregation, while late-arriving males exhibited transient movement across aggregations. Though large males were more likely to hover, declines in body size over time suggested variable sexual selection for large males. Thus, males likely exhibit alternative reproductive strategies to maximise their reproductive success. We demonstrate the importance of multi-year studies to explain mechanisms underlying male reproductive strategies.