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Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/33711

Title: The Hormonal Regulation of Non-breeding Territorial Aggression in North American Red Squirrels (Tamiasciurus hudsonicus)
Authors: Bettio, Adam N.
Advisor: Boonstra, Rudy
Department: Ecology and Evolutionary Biology
Keywords: Non-breeding aggression
Red squirrels
DHEA
Oestradiol
Adrenals
Gonads
ACTH
GnRH
Issue Date: 3-Dec-2012
Abstract: Classically, testosterone (T) was considered the principal regulator of aggression. However, recent studies in birds have found aggression and T uncoupled during the non-breeding season. Circulating testosterone comes with costs such as immunosuppression and energy expenditure. Instead, the pro-hormone, dehydroepiandrosterone (DHEA), is circulated and activated within the brain via conversion into oestradiol (E2), avoiding the costs associated with T. At present the site of DHEA synthesis is unknown. My thesis investigated the existence of an analogous pathway in non-breeding red squirrels (Tamiasciurus hudsonicus) with two studies: (a) a field study investigating the effects of E2 on aggression and (b) a laboratory study that attempted to determine the site of DHEA synthesis. I conclude that E2 regulates non-breeding aggression in red squirrels and that the adrenals are not the site of DHEA synthesis. My results suggest the existence of a mammalian analogue to the regulatory pathway found in birds.
URI: http://hdl.handle.net/1807/33711
Appears in Collections:Master

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