Is the flight and foraging activity of small-size stingless bee affected by the urban heat island? The case of Plebeia catamarcensis (Meliponini) in Cordoba city (Argentina). Issue 5 (20th October 2022) - Zeballos, Manuel
Abstract: Urban heat island (UHI) effect is considered one of the major drivers of changes in insect behavior within cities. Here, we evaluated the flight and the nectar and pollen foraging activities of the southernmost stingless bee, Plebeia catamarcensis, along a land surface temperature gradient in central and peri-urban areas of the city of Cordoba (Argentina), as a proxy for the UHI effect. Flight and foraging activity were recorded in ten colonies located along the temperature gradient in summer. We registered the bees' activity in three time-bands (morning, midday and afternoon) through video recording. The temperature gradient was obtained from Landsat 8 data in a buffer around each nest. Our results showed that overall flight activity as well as nectar foraging significantly increased with temperature. Pollen foraging, however, was significantly explained by time-bands with the highest activity concentrated in the morning, and independently of the temperature gradient. In addition, nectar and pollen foraging patterns were negatively associated. Whereas P. catamarcensis would take advantage of higher urban temperatures to forage nectar, the pollen foraging strategy may hide an avoidance competition behavior sustained by the limited pollen availability compared with that of nectar. As a first attempt to address the UHI effect on a stingless bee, our results address the potential ability of the southermost P. catamarcensis populations to overcome the negative effects of urban warming observed for other bees.