Plasma Testosterone Concentrations in Adult Tree Swallows During the Breeding Season

Thumbnail Image
Supplemental Files
Date
2011-09-01
Authors
Staley, Molly
Vleck, David
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Person
Vleck, Carol
Professor Emerita
Research Projects
Organizational Units
Organizational Unit
Ecology, Evolution and Organismal Biology

The Department of Ecology, Evolution, and Organismal Biology seeks to teach the studies of ecology (organisms and their environment), evolutionary theory (the origin and interrelationships of organisms), and organismal biology (the structure, function, and biodiversity of organisms). In doing this, it offers several majors which are codirected with other departments, including biology, genetics, and environmental sciences.

History
The Department of Ecology, Evolution, and Organismal Biology was founded in 2003 as a merger of the Department of Botany, the Department of Microbiology, and the Department of Zoology and Genetics.

Dates of Existence
2003–present

Related Units

Journal Issue
Is Version Of
Versions
Series
Abstract

We studied seasonal profiles of circulating testosterone concentrations among male and female adult Tree Swallows (Tachycineta bicolor) breeding in nest-box colonies near Ames, Iowa, USA. Mean plasma testosterone in males was elevated during nest establishment (0.63 ± 0.86 ng/ml) and incubation stages (0.28 ± 0.26 ng/ml), and was significantly lower after hatching (0.03 ± 0.05 ng/ml) when males began provisioning nestlings. Male swallows do not incubate and high testosterone during the incubation stage may facilitate pursuit of extra-pair matings. Female testosterone concentrations were an order of magnitude lower than those of males (nest establishment, mean  =  0.06 ± 0.09 ng/ml) and did not change significantly over the breeding season. These testosterone profiles support the hypothesis that elevated testosterone in males is associated with defense behaviors and obtaining additional mating opportunities during the first part of the breeding season, but is incompatible with parental care once the eggs have hatched.

Comments

This article is from The Wilson Journal of Ornithology 123 (2011); 608, doi: 10.1676/10-142.1. Posted with permission.

Description
Keywords
Citation
DOI
Copyright
Sat Jan 01 00:00:00 UTC 2011
Collections