Inside the study of behavioural thermoregulation...
Physiological thermoregulation in the heat is costly for endotherms, entailing large and rapidly increasing water expenditure, risks of blood chemistry changes associated with panting, and performance costs of adaptive hyperthermia. Changes in behaviour (e.g. reduction in activity) and microsite selection (choosing shaded, cool locations in the landscape) can reduce some of these costs by reducing the animal’s ‘heat load’. However, there is no such thing as a free lunch and these strategies (collectively called ‘behavioural thermoregulation’) carry their own baggage. This is because they require animals to alter their patterns of behaviour, and these alterations can carry significant fitness consequences.
In my research group, we study the effects of temperature on behaviour, and the knock-on consequences of this for various fitness proxies, including reproductive success and body mass changes. We look at species traits that may exacerbate or reduce these costs, for example foraging strategies that place individuals under excessive heat loads, or interactions between heat stress and already costly breeding systems. We are very interested in life-history strategies that may buffer individuals from the costs of thermoregulatory behavioural trade-offs, for example, group-living in arid zone birds, and how the structure of social groups is affected by heat stress.
We work on a range of Kalahari species including southern fiscals, southern yellow-billed hornbills, sociable weavers, white-browed sparrow-weavers and southern pied babblers. In the Fynbos biome, we address similar questions looking at cape rockjumpers and cape sugarbirds.
Dr. Susan Cunningham, principal investigator
Hot Drongos - foraging, parental care and thermoregulatory trade-offs – Ryan Olinger
Thermoregulation and risk-taking – Penny Pistorius
Dehydration versus hyperthermia: is shade a limiting resource for birds drinking at artificial water holes in the Kalahari? – Salamatu Abdu
The costs of keeping cool – trade-offs between thermoregulation and foraging in Southern Pied Babblers – Kate du Plessis
Cunningham, S.J., Kruger, A.C., Nxumalo, M.P. & Hockey, P.A.R. 2013. Identifying biologically meaningful hot-weather events using threshold temperatures that affect life-history. PLoS ONE 8(12): e82492.
Cunningham, S.J., Martin, R.O., Hojem, C.L. & Hockey, P.A.R. 2013. Temperatures in excess of critical thresholds threaten nestling growth and survival in a rapidly-warming arid savanna: a study of common fiscals. PLoS ONE 8 (9): e74613
Du Plessis, K., Martin, R., Hockey, P.A.R., Cunningham, S.J., & Ridley, A. 2012. The costs of keeping cool in a warming world: implications of high temperatures for foraging, thermoregulation and body condition of an arid zone bird. Global Change Biology 18: 3063-3070.