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Pheasant sexual ornaments reflect nutritional conditions during early growth.

Author:
  • Thomas Ohlsson
  • Henrik Smith
  • Lars Råberg
  • Dennis Hasselquist
Publishing year: 2002
Language: English
Pages: 21-27
Publication/Series: Royal Society of London. Proceedings B. Biological Sciences
Volume: 269
Issue: 1486
Document type: Journal article
Publisher: Royal Society

Abstract english

Differences in growth conditions during early life have been suggested to cause long-lasting effects on morphology and quality of adult birds. We experimentally investigated the effect of early growth conditions on the expression of sexual ornaments later in life in male ring-necked pheasants (Phasianus colchicus). We also investigated the effects on immune function, as it could be a functional link between early nutrition and ornament expression. We manipulated the dietary protein intake during the first eight weeks post hatching. Males receiving fodder with 27% protein during the first three weeks of life grew larger and more colourful wattles when sexually mature than males receiving a low-protein diet (20.5% protein). Spur length was unaffected by diet treatment. Manipulation of food protein levels during weeks 4-8 after hatching had no effect on the development of ornaments. The different protein treatments had no long-term effect on either humoral or cell-mediated immune responses. There was, however, a positive relationship between spur length and cell-mediated immune responsiveness. Our study shows that expression of a sexual ornament in adult pheasants reflects nutritional conditions early in life. Because the expression of secondary sexual ornaments is affected by conditions during early growth, by selecting more ornamented males, females would choose mates that are superior at handling early nutritional stress. If the susceptibility to early nutritional stress also has a hereditary basis, females may benefit by obtaining 'good genes'.

Keywords

  • Ecology
  • Biological Sciences
  • Body Composition : drug effects
  • Animal
  • Color
  • Dietary Proteins : administration & dosage : pharmacology
  • Male
  • Nutritional Requirements
  • Support Non-U.S. Gov't
  • Sex Characteristics
  • Animal Feed
  • Animal Nutrition
  • Birds : growth & development : immunology : physiology

Other

Published
  • Molecular Ecology and Evolution Lab
  • ISSN: 1471-2954
Henrik Smith
E-mail: henrik [dot] smith [at] biol [dot] lu [dot] se

Professor

Biodiversity

+46 46 222 93 79

+46 70 978 20 56

E-C313

50

Director

Centre for Environmental and Climate Research (CEC)

+46 46 222 93 79

+46 70 978 20 56

C313

Sölvegatan 37, Lund

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Centre for Animal Movement Research
Evolutionary Ecology, Department of Biology
Ecology building S-223 62 Lund Sweden