Meeting Abstract
Eusocial Damaraland mole-rats (DMR) live in colonies made up of a single breeding pair and their offspring. The offspring are non-breeders and do not express sexual behavior within their natal colony and only in the presence of unfamiliar, opposite-sex conspecifics do sexual behaviors manifest. Thus, familiarity with colony mates appears to preclude mating, resulting in inbreeding avoidance within colonies. Previous results indicate that siblings separated from each other for 5 weeks treat each other as unfamiliar and readily mate with one another. Thus, genetic relatedness does not appear to explain the inbreeding avoidance in DMR colonies. Familiarity alone does not sufficiently explain the regulation of sexual behaviors either, since breeding pairs continue to mate after becoming “familiar.” The presence or absence of sexual behaviors defines two types of relationships: sibling and breeder. Our hypothesis regarding the development of these relationships is that the presence or absence of sexual behavior during the initial interaction determines the long-term relationship between individuals. We tested this hypothesis by either restricting or allowing physical contact upon first interaction between opposite-sex unrelated non-breeders, then allowing them olfactory access to one another each day for two weeks (familiarization period). Pairs that were not allowed to mate upon first interaction developed a sibling-like relationship when paired without restraint, while pairs that were allowed to mate developed a breeding relationship and expressed significantly more sexual behaviors when paired. Inbreeding avoidance may depend upon the absence of sexual behaviors when siblings are first familiarizing within the colony. Likewise, breeding pairs may develop due to the expression of sexual behaviors upon first meeting.
