D3259: The effect of climate change on two primitively eusocial bees

High altitude regions are likely to be highly impacted by climate change. Pollinators such as bees in these regions may adjust their life history traits to adapt to changes within their ecosystems. Because eusociality is associated with reduced mortality and increased resilience to resource variation, primitively eusocial bees may become increasingly social. Using data from 2010-2017 in the Irwin Bees Dataset, I evaluated two primitively eusocial bees, Halictus virgatellus (Halictidae) and Halictus rubicundus (Halictidae), to investigate the hypothesis that a warming climate will increase the probability of sociality in primitively eusocial bees. Social bees form two broods: one of workers, and one of breeders, while solitary bees typically have one brood. Measuring the difference in male and female emergence over time allowed me to assess sociality. I expected that bees that are eusocial would only produce males near the end of the female flight season, whereas bees that are solitary would produce males and females throughout their flight season. I found no significant effects, suggesting that Halictus virgatellus and Halictus rubicundus are not changing in sociality. A lack of male abundance data may have influenced these trends. While this study found no significant trends in Halictus virgatellus and Halictus rubicundus, the same analyses described here could be used to evaluate other species present in long-term datasets. By better understanding changes in social strategies, it is possible to evaluate how a changing climate may affect the expression of life history traits which could buffer bees from the effects of climate warming.