You are here

UCF Digital Collections ยป ETD Collection

THE INFLUENCE OF SEXUAL SELECTION ON BEHAVIORAL AND PHYSIOLOGICAL MECHANISMS UNDERLYING REPRODUCTIVE SUCCESS IN MALE CAPE GROUND SQUIRRELS (XERUS INAURIS)

Download pdf | Full Screen View

Date Issued:
2010
Abstract/Description:
Sexual selection is considered a powerful evolutionary force responsible for the enormous diversity found in reproductive morphology, physiology, and behavior. I addressed questions related to selection in the Cape ground squirrel (Xerus inauris), a species characterized as highly social and promiscuous. These attributes often are responsible for variance in male reproductive success and as such, sexual selection theory predicts increased opportunity for sexual selection. I confirm that the predominant mechanism underlying genital evolution and competition for paternity in X. inauris is sperm competition. I find evidence that investment in sperm competition is costly and may reflect immunocompetence. I quantify reproductive success as it relates to alternative male tactics and female resource distribution. I find that male X. inauris alternative reproductive tactics differ within and across populations most likely due to differences in female resource distribution. In areas where females are evenly distributed, dispersed males encounter more estrous females, and therefore have increased breeding opportunities. However, the decision to remain natal does not preclude reproduction. I determine that these tactics are most likely conditional with equal fitness payoffs. Males, regardless of tactic, invest more in post-copulatory competition (e.g. sperm competition, copulatory plugs) than males within a population with a clustered distribution of breeding females. In the latter area, males form dominance hierarchies that affect copulatory success and lead to greater skews in reproduction among males. Both sites have evidence of a highly skewed variance in reproduction and intense sexual selective pressure. My results suggest these populations have increased opportunities for selection but that different mechanisms of intrasexual competition may result in rapid evolutionary change within this species.
Title: THE INFLUENCE OF SEXUAL SELECTION ON BEHAVIORAL AND PHYSIOLOGICAL MECHANISMS UNDERLYING REPRODUCTIVE SUCCESS IN MALE CAPE GROUND SQUIRRELS (XERUS INAURIS).
30 views
17 downloads
Name(s): Manjerovic, Mary, Author
Waterman, Jane, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2010
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Sexual selection is considered a powerful evolutionary force responsible for the enormous diversity found in reproductive morphology, physiology, and behavior. I addressed questions related to selection in the Cape ground squirrel (Xerus inauris), a species characterized as highly social and promiscuous. These attributes often are responsible for variance in male reproductive success and as such, sexual selection theory predicts increased opportunity for sexual selection. I confirm that the predominant mechanism underlying genital evolution and competition for paternity in X. inauris is sperm competition. I find evidence that investment in sperm competition is costly and may reflect immunocompetence. I quantify reproductive success as it relates to alternative male tactics and female resource distribution. I find that male X. inauris alternative reproductive tactics differ within and across populations most likely due to differences in female resource distribution. In areas where females are evenly distributed, dispersed males encounter more estrous females, and therefore have increased breeding opportunities. However, the decision to remain natal does not preclude reproduction. I determine that these tactics are most likely conditional with equal fitness payoffs. Males, regardless of tactic, invest more in post-copulatory competition (e.g. sperm competition, copulatory plugs) than males within a population with a clustered distribution of breeding females. In the latter area, males form dominance hierarchies that affect copulatory success and lead to greater skews in reproduction among males. Both sites have evidence of a highly skewed variance in reproduction and intense sexual selective pressure. My results suggest these populations have increased opportunities for selection but that different mechanisms of intrasexual competition may result in rapid evolutionary change within this species.
Identifier: CFE0003400 (IID), ucf:48402 (fedora)
Note(s): 2010-08-01
Ph.D.
Sciences, Department of Biology
Masters
This record was generated from author submitted information.
Subject(s): sexual selection
sperm competition
immunocompetence
alternative mating tactics
mating systems
promiscuity
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0003400
Restrictions on Access: campus 2011-12-01
Host Institution: UCF

In Collections