Increasing thermal stress with flight distance in stingless bees (Melipona subnitida) in the Brazilian tropical dry forest: Implications for constraint on foraging range.

The thoracic temperature (T) of foraging bees usually exceeds ambient air temperatures (T) by several degrees. In hot tropical climate zones, therefore, individuals may reach body temperatures close to their critical thermal maxima, which might constrain their activity. In the present study, we tested the hypothesis that thermal stress increases with flight distance in nectar foragers of M.

Stingless bees and their adaptations to extreme environments.

Nearly half of all terrestrial tropical ecosystems around the globe comprise dry forests, characterised through elevated temperatures all year round, and short rainy seasons at irregular intervals. The consequent water deficit over several consecutive months limits the availability of floral resources to often very brief and unpredictable periods, which poses a challenge to the maintenance of perennial colonies in highly eusocial bees. Thus, only few highly eusocial bees occur permanently in tropical dry forests, among them some highly adapted species of stingless bees (Apidae, Meliponini).