Abstracts

Abstract: Mate choice based on age is poorly understood among Cervids. We used genetic-based parentage assignments from a white-tailed deer (Odocoileus virginianus) population to evaluate age differences between breeding pairs under differing herd demographics. Our study population consisted of native deer enclosed in a 430-acre captive facility in east-central Alabama. Tissue samples were collected beginning in 2007, and microsatellite DNA analysis was used to build a pedigree. Analysis of parentage revealed 37 breeding pairs with 95% confidence. From 2008-09, the population had a 1:2 buck:doe ratio with an immature male age structure ( ̄x̅ = 2.28 years) which was typical of a heavily hunted population. By 2012, the population had a 1.5:1 buck:doe ratio with a more mature male age structure ( ̄x̅ = 3.69 years) which was typical of a herd managed for quality. We combined years into 2 periods by male age structure (2007-2009, 'immature'; 2010-2012, 'mature') and found that mean age difference (doe age minus buck age) within breeding pairs was dissimilar (P = 0.04) when compared between the two periods. Chi-square tests indicated mating with respect to age was not random (P < 0.05). Mean conception dates occurred one week sooner when more mature males were present. The effects of age differences between breeding individuals, combined with earlier conception, illustrate how changes in population demographics can affect the timing of the breeding season. The result is less late born fawns with more mature males present, and a compression of gestation dates which could help mitigate impacts of neonatal predation.