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Heritability of corticosterone response and changes in life history traits during selection in the zebra finch

journal contribution
posted on 01.03.2006, 00:00 authored by M Evans, M Roberts, Kate BuchananKate Buchanan, A Goldsmith
Vertebrates respond to environmental stressors through the neuro-endocrine stress response, which involves the production of glucocorticoids. We have selected independent, duplicate divergent lines of zebra finches for high, low and control corticosterone responses to a mild stressor. This experiment has shown that over the first four generations, the high lines have demonstrated a significant realized heritability of about 20%. However, the low lines have apparently not changed significantly from controls. This asymmetry in response is potentially because of the fact that all birds appear to be showing increased adaptation to the environment in which they are housed, with significant declines in corticosterone response in control lines as well as low lines. Despite the existence of two- to threefold difference in mean corticosterone titre between high and low lines, there were no observed differences in testosterone titre in adult male birds from the different groups. In addition, there were no consistent, significant differences between the lines in any of the life history variables measured – number of eggs laid per clutch, number of clutches or broods produced per pair, number of fledglings produced per breeding attempt, nor in any of egg, nestling and fledgling mortality. These results highlight the fact that the mechanisms that underlie variation in the avian physiological system can be modified to respond to differences between environments through selection. This adds an additional level of flexibility to the avian physiological system, which will allow it to respond to environmental circumstances.

History

Journal

Journal of evolutionary biology

Volume

19

Issue

2

Pagination

343 - 352

Publisher

Wiley - Blackwell Publishing

Location

Oxford, England

ISSN

1010-061X

eISSN

1420-9101

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2005, European Society for Evolutionary Biology