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Repeatable intra-individual variation in plasma testosterone concentration and its sex-specific link to aggression in a social lizard


While, GM and Isaksson, C and McEvoy, J and Sinn, DL and Komdeur, J and Wapstra, E and Groothuis, TGG, Repeatable intra-individual variation in plasma testosterone concentration and its sex-specific link to aggression in a social lizard , Hormones and Behavior, 58, (2) pp. 208-213. ISSN 0018-506X (2010) [Refereed Article]

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DOI: doi:10.1016/j.yhbeh.2010.03.016


Individual hormone profiles can be important generators of phenotypic variation. Despite this, work on the consequences of hormone profiles has traditionally ignored the large inter-individual variation within natural populations. However, recent research has advocated the need to explicitly consider this variation and address its consequences for selection. One of the key steps in this process is examining repeatability in hormone profiles and their links to behavioral traits under selection. In this study we show that individuals within a free-ranging population of the Australian lizard Egernia whitii exhibit temporal repeatability in their circulating baseline testosterone concentrations as well as their aggressive response towards conspecific intruders. Furthermore, we show significant, sex-specific links between testosterone and aggression. Specifically, testosterone and aggression is negatively linked in males, while there is no relationship in females. As conspecific aggression has significant consequences for fitness-related traits (parental care, mating strategies) in this species, inter-individual variation in testosterone concentrations, through their effects on aggression, could have important implications for individual fitness. We discuss the potential causes and consequences of hormonal repeatability as well as provide explanations for its sex-specific links with aggression. Specifically, we suggest that these patterns are the result of alternative hormonal pathways governing aggression within Egernia and may indicate a decoupling of aggression and testosterone across the sexes.

Item Details

Item Type:Refereed Article
Keywords:Animal personalities, Egernia whitii, Hormonal repeatability, Reptile, Sex steroids
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Assessment and management of Antarctic and Southern Ocean ecosystems
UTAS Author:While, GM (Dr Geoff While)
UTAS Author:McEvoy, J (Dr Joanne McEvoy)
UTAS Author:Sinn, DL (Dr David Sinn)
UTAS Author:Wapstra, E (Associate Professor Erik Wapstra)
ID Code:64661
Year Published:2010
Web of Science® Times Cited:43
Deposited By:Zoology
Deposited On:2010-08-16
Last Modified:2011-04-08
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