Behavioural and developmental responses of a stingless bee (Scaptotrigona depilis) to nest overheating

Abstract

In this study, we investigate the behavioural response of the highly eusocial stingless bee Scaptotrigona depilis to high temperatures. We found that nest temperature in the brood area can be up to 2.5 °C lower relative to a control empty box during hot periods. We showed that high temperatures increase both water collection and wing fanning behaviour at the colony level, suggesting that these behaviours are adaptations to cooling the nest in this species. Additionally, we measured survival and development time of pupae incubated at five different constant temperatures (22, 26, 30, 34 and 38 °C). We found that the development time of S. depilis brood significantly varied between treatments and had a strong negative correlation with temperature. Brood survived over a large range of incubation temperatures; however, extreme temperatures (22 and 38 °C) were almost 100 % lethal, highlighting the importance of thermoregulation, at least in extreme conditions.