The Importance of Social Condition in the Hormonal and Behavioral Responses to an Acute Social Stressor in the Male Siberian Dwarf Hamster (Phodopus sungorus) |
| |
Authors: | William Lesley R. Castro Kathleen S. Matt |
| |
Affiliation: | aDepartment of Zoology, Arizona State University, Tempe, Arizona, 85287;bDepartment of Exercise Science and Physical Education, Arizona State University, Tempe, Arizona, 85287 |
| |
Abstract: | Social condition is an important factor in determining the behavioral and hormonal responses to a social stressor in the Siberian dwarf hamster (Phodopus sungorus). We predict that males housed with a female or a family (female and pups) will show an increase in the magnitude of the behavioral and hormonal responses to a male intruder compared to those of individually housed males. Three treatment groups were studied: individually housed males that had been previously group-housed in same-sex colonies (males,n= 10), males housed with a female (male + female,n= 9), and males housed with their female and pups (male + family,n= 12). Males were monitored for aggressive behavior toward an intruder male for 10 min. Blood samples were taken at baseline and after the encounter. Male + female and male + family groups spent more time in aggressive behavior (P< 0.05), such as attacking (P< 0.05) and fighting (P<0.05), than did individually housed males. These same groups showed significant increases in plasma cortisol after the encounter (P< 0.01) whereas there were no significant increases in plasma cortisol in solitary males. All groups showed significantly lower levels of plasma testosterone (male,P< 0.001, male + female,P< 0.05; male + family,P< 0.01) whereas a significant increase in prolactin occurred only in the male + family group (P< 0.05). There was a significant positive correlation between postencounter cortisol levels and total number of minutes spent in aggressive behavior (P< 0.05). These results demonstrate that the introduction of a novel intruder male results in an activation of the hypothalamic–pituitary–adrenocortical axis and a suppression of the reproductive axis. Furthermore, pairing of a male with a female alters the behavioral and hormonal responses to an intruder male. |
| |
Keywords: | social condition stress hormones aggression hamster |
本文献已被 ScienceDirect 等数据库收录! |
|