Molecular Evaluation of the White-tailed Deer (Odocoileus Virginianus) Mating System

Abstract

We used genetic-based paternity assignments from 3 diverse populations of white-tailed deer (Odocoileus virginianus) to evaluate the long-held assumption that male reproductive success in this species is highly skewed toward a small number of mature, dominant individuals. The study populations represented a range of adult sex ratios and male age structures. Male reproductive success was distributed among a large number of males in all populations, with no evidence for highly skewed access to mating for any individual male. Surprisingly, physically immature males (1.5 and 2.5 years of age) collectively fathered 30-33% of offspring in all populations, even where mature males were present. Ecological and behavioral variables appear to constrain the ability of individual males to monopolize access to females, resulting in a wider distribution of reproductive success than expected based on previous ecological and behavioral studies of white-tailed deer. Qualitative differences in the distribution of male reproductive success among study sites suggested that demographic attributes such as adult sex ratio and male age structure might influence the degree of competition for mates. Further study incorporating known-age cohorts or integrating movements and behavior is necessary for understanding the effects of population demographics as well as the physical and behavioral attributes that confer reproductive success in diverse populations of white-tailed deer.

Effect of male age structure on reproduction in white‐tailed deer

“…There are likely multiple reasons that would explain why changes in the age structure of a male white‐tailed deer population would have limited effects on timing and synchrony of breeding. Foremost, breeding is not dominated by older age classes (Sorin , DeYoung et al ). DeYoung et al () studied 3 populations where the proportion of ≥3.5‐year‐old males was 37–57%, yet 1.5‐ and 2.5‐year‐old males sired 30–33% of offspring.…”

“…Foremost, breeding is not dominated by older age classes (Sorin , DeYoung et al ). DeYoung et al () studied 3 populations where the proportion of ≥3.5‐year‐old males was 37–57%, yet 1.5‐ and 2.5‐year‐old males sired 30–33% of offspring. In our study the proportion of ≥3.5‐year‐old males in the population increased from approximately <4% to 11% as harvest rates of ≥2.5‐year‐old males declined from 0.81 to 0.59 (Wallingford et al ).…”

Inefficiency of evolutionarily relevant selection in ungulate trophy hunting

“…Although mature animals do a disproportionate amount of the mating (McCullough ), information is now emerging from bovids and cervids that subordinate males are more successful in fathering offspring than previously thought (Hogg and Forbes , Coltman et al , Sorin , DeYoung et al ). DeYoung et al () investigated patterns of male white‐tailed deer mating success with genetic paternity testing and reported 30–33% of the white‐tailed deer fawns on 3 study areas were sired by physically immature 1.5‐ and 2.5‐year‐old males. The remainder were sired by males ≥3.5 years old.…”

Reproductive effort and success of males in scramble‐competition polygyny: Evidence for trade‐offs between foraging and mate search

“…Spatial memory and mobility are important because prior knowledge of female locations is a key component of reproductive success, given oestrous is temporally brief (Murai, Koga, & Yong, ; Sandell & Liberg, ; Schwagmeyer, ). Relative to resource‐defence mating systems, reproductive success is distributed among many males, and multiple paternities are common (DeYoung et al., ; Schwagmeyer, ). Further, the physical correlates of male reproductive success in scramble competition are poorly understood (DeYoung, Demarais, Honeycutt, Gee, & Gonzales, ; Jones, Strickland, Demarais, & DeYoung, ; Marchinton & Hirth, ).…”