Can social behaviour, particularly load-sharing, buffer against fitness costs associated with heat stress?
PhD student: Amanda Bourne
Supervisors: Dr Susan Cunningham, Dr Amanda Ridley (PI Pied Babbler Research Project), Dr Claire Spottiswoode
Other collaborators: Prof. Andrew McKechnie
Hot Birds work on Southern Pied Babblers (Turdoides bicolor) is carried out in collaboration with Prof. Amanda Ridley's Pied Babbler Research Project, based at Kuruman River Reserve. Prof. Ridley curates a 12-year behavioural dataset associated with this unique population.
The primary focus of Amanda Bourne's research is to test whether co-operation can buffer negative effects of environmental extremes in a warming world, with a particular focus on whether load lightening can reduce the costs of heat stress. Amanda's first field season will start in September 2016.
Climate change is increasing the frequency, intensity & duration of heat waves. Temperatures above critical thresholds affect fitness & population persistence of animals by forcing trade-offs between essential behaviours & heat stress mitigation. However co-operation allows sharing of workload across individuals (load-lightening) and may reduce costs of time spent on thermoregulation. We predict costs of heat stress will decline with group size, so that babblers in larger groups suffer lower costs during periods of elevated temperature, therefore attaining better fitness outcomes. We will assess the interaction between group size & temperature on different components of fitness, including physiological costs of heat stress, changes in behaviour and short and long-term reproductive and survival consequences; taking advantage of natural variation in group size.
This study will provide the first direct test of sociality as a buffer against impacts of climate warming, with important implications for the management & predictive population modelling of social species, including our own, in the face of current & future climate change.