Wild bees are vital for maintaining biodiversity and food security. However, bees are currently threatened by the conversion of their natural habitat into urban areas, among many other factors. Here, we examine how five wild bee species respond to increasing urbanization according to their functional traits across the most populous city in Canada, which is also the fourth largest in North America. We investigate the effect of urbanization on bee demography and morphology as measured by abundance, sex ratio, body size, and foraging efforts. We found more bees in medium-urbanized sites and larger bees in medium and high-urbanized sites for two species (Eucera pruinosa and Ceratina calcarata). We found higher wing wear in low and medium-urbanization sites. Our data suggests that urbanization potentially affects these wild bee species' abundance, body size, and foraging efficiency. We further discuss these findings according to the ecology of urbanization and the biology of each species.Implications for insect conservation Human activity can significantly alter natural habitats, causing adverse effects on wild bees and ultimately affecting their survival. Considering the crucial role bees play in pollinating numerous crop and wild plant species, which, in turn, sustains biodiversity and food security, it is crucial to assess their response to the increasing levels of urbanization.
