Behavioural thermoregulation and heat stress in southern blossom bats (Syconycteris australis)

Blossom bats, like many other pteropodid species, face increased risk of severe heat stress and death due to rising ambient temperatures associated with climate change. Our observational captive study investigates the behavioural thermoregulatory responses to Ta between 17 and 36°C in the southern blossom bat (Syconycteris australis). Under hot conditions, postural adjustment to increase surface area and licking for evaporative cooling were observed, but wing flapping, seen in many larger pteropodid species, was absent. Our study found a significant increase in licking behaviour for temperatures between 33 and 36°C, indicating that onset of severe heat stress commences by Ta of 36°C for S. australis captured in NSW. Field observations in published literature suggest that S. australis likely attempts to avoid hot Ta by appropriate choice of microclimate. In the face of rising temperatures associated with climate change, retaining adequate thermal refuge options within daily flying range of foraging sites is critical to the survival of this and probably other small solitary tree-roosting pteropodids.