Electronic Theses and Dissertations

Date

2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Biology

Committee Chair

David Freeman

Committee Member

Helen Sable

Committee Member

Matthew Parris

Committee Member

Andrew Liu

Abstract

Damaraland mole-rat (DMR; Fukomys damarensis) colonies are composed of the breeding female (often termed the queen), her breeding partner, and their offspring. The non-breeding offspring do not expend energy to increase their fitness directly, they contribute to the reproductive effort of the breeding pair by: helping to care for their siblings, foraging for food, defending the colony from predators, and maintaining and enlarging the burrow system. DMR practice strict inbreeding avoidance within their natal colonies and, as a result, are considered obligate out-breeders. The expression of sexual behaviors in DMR does not depend solely upon exposure to an unfamiliar conspecific, as opposite sex siblings separated for a period of 5 weeks will express sexual behaviors towards one another. These findings indicate that regulation of mating behavior is not based on genetic relatedness per se, but more so on familiarity between two individuals. Exposure to an unfamiliar conspecific depends upon dispersal from the natal colony. This process exposes DMR to novel stimuli, as well as the challenge of finding a mate and building a new burrow system; all of which may initiate a stress-response. The traditional generalization is that the activation of the hypothalamic-pituitary-adrenal axis under stress has an inhibitory effect on mating behavior. The repression of the reproductive axis during dispersal would be maladaptive, as mating opportunities are essentially non-existent for non-breeding colony members unless they encounter unfamiliar individuals, which happens primarily through the process of dispersal. Our findings indicate that removal from the colony may act as a stimulus triggering mating behavior. A result of colonial living in a species with low dispersal rates is the formation of stable pair bonds. DMR individuals can live for 18 years or more in captivity and can successfully breed from less than 1 year of age, meaning that pairs have the potential to form bonds that last for years, possibly their entire lives. This situation leads to an apparent sexual monogamy, although the fidelity of the pair bonding is tested when foreign individuals are introduced. Our results indicate the lack of partner preference in DMR breeding pairs.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest

Download

Share

COinS