Introduction:

Increasing urbanization has endangered many species to an unknown extent. Stingless bees (Apidae: Meliponini) are highly important pollinators of tropical plants. Some species are well adapted to urban areas and use man-made structures to build their nests. In Costa Rica, there are 59 stingless bee species, but no account of their urban richness and abundance has ever been made.

Objective:

To describe the composition and dynamics of the social bee community on the campus of the University of Costa Rica in San José over a six-year period.

Methods:

We systematically searched for stingless bee nests (active colonies) in trees, buildings, walls and other man-made infrastructure within a 31-hectare section of the campus in 2016 and 2022. We investigated species-specific nest heights and the host plant species chosen for nesting.

Results:

A maximum of 86 active nests were identified, consisting of five species of five genera (Lestrimellita, Partamona, Scaptotrigona, Tetragonisca, and Trigona). From 2016 to 2022, the stingless bee abundance increased by 26.5 %, but the species composition remained the same. Tree cavities were the most attractive nesting locations, and their use increased within the sampling period. Overall nest survival was >64.3 % for the study period.

Conclusion:

All bee species utilized a variety of tree species, but strangler figs (Ficus spp., Moraceae) were the most important for nest construction. Nest height depended on the species and architecture. This work provides a framework for future studies on tropical social bee communities in urban areas and offers valuable information on their nesting biology in this habitat.