Nesting in human-made versus natural cavities affects colony demography and nest architecture in an urban-adapted Neotropical stingless bee

Abstract Habitat loss and urbanisation create challenging environments for many bee species, but some show a remarkable ability to adapt to urban environments, e.g. by nesting in buildings and foraging in gardens or parks. Little is currently known about the consequences of living in natural versus anthropogenic cavities for social bees. Tetragonisca angustula is one of the most common Neotropical stingless bees and frequently nests in cavities such as in stone walls and other human constructions. We compared colony traits between T. angustula colonies housing in trees versus human constructions to better understand the potential advantages and disadvantages of cavity choice for this bee. We found that colonies nesting in tree cavities had higher foraging traffic, suggesting they have a larger colony size. These colonies also had disproportionately more entrance guards and longer entrance tubes. In contrast, worker body size did not differ between nesting substrates. We tested if natural nests might experience higher predation risks by assessing the presence of predators near entrances but found no difference between the two nest types. Finally, we found that colony size estimates correlated across years only in human cavities, indicating that human constructions might provide a more stable environment. Our findings suggest that anthropogenic cavities significantly impact colony traits, mainly colony size, but that they might provide more stability. Given the increase of urbanisation, more research on the ability of bees to use urban spaces is needed to understand the impacts of urban expansion on bees.