Insect thermal tolerance: what is the role of ontogeny, ageing and senescence?
Article first published online: 28 JUN 2008
© 2008 The Authors Journal compilation © 2008 Cambridge Philosophical Society
Volume 83, Issue 3, pages 339–355, August 2008
How to Cite
Bowler, K. and Terblanche, J. S. (2008), Insect thermal tolerance: what is the role of ontogeny, ageing and senescence?. Biological Reviews, 83: 339–355. doi: 10.1111/j.1469-185X.2008.00046.x
- Issue published online: 21 JUL 2008
- Article first published online: 28 JUN 2008
- (Received 11 December 2007; revised 29 April 2008; accepted 08 May 2008)
- temperature tolerance;
- chill coma;
- phenotypic plasticity
Temperature has dramatic evolutionary fitness consequences and is therefore a major factor determining the geographic distribution and abundance of ectotherms. However, the role that age might have on insect thermal tolerance is often overlooked in studies of behaviour, ecology, physiology and evolutionary biology. Here, we review the evidence for ontogenetic and ageing effects on traits of high- and low-temperature tolerance in insects and show that these effects are typically pronounced for most taxa in which data are available. We therefore argue that basal thermal tolerance and acclimation responses (i.e. phenotypic plasticity) are strongly influenced by age and/or ontogeny and may confound studies of temperature responses if unaccounted for. We outline three alternative hypotheses which can be distinguished to propose why development affects thermal tolerance in insects. At present no studies have been undertaken to directly address these options. The implications of these age-related changes in thermal biology are discussed and, most significantly, suggest that the temperature tolerance of insects should be defined within the age-demographics of a particular population or species. Although we conclude that age is a source of variation that should be carefully controlled for in thermal biology, we also suggest that it can be used as a valuable tool for testing evolutionary theories of ageing and the cellular and genetic basis of thermal tolerance.