Male body size predicts reproductive success but not within-clutch paternity patterns in gopher tortoises (Gopherus polyphemus)

Journal Article · Thu Jul 19 00:00:00 EDT 2018 · Journal of Heredity

DOI:https://doi.org/10.1093/jhered/esy036· OSTI ID:1828596

White, K. Nicole ^[1]; Rothermel, Betsie B. ^[2]; Zamudio, Kelly R. ^[3]; Tuberville, Tracey D. ^[4]

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1. Univ. of Georgia, Aiken, SC (United States); Univ. of Georgia, Athens, GA (United States); Archbold Biological Station, Venus, FL (United States); SREL
2. Archbold Biological Station, Venus, FL (United States)
3. Cornell Univ., Ithaca, NY (United States)
4. Univ. of Georgia, Athens, GA (United States)

In many vertebrates, body size is an important driver of variation in male reproductive success. Larger, more fit individuals are more likely to dominate mating opportunities, skewing siring success and resulting in lower effective population sizes and genetic diversity. The mating system of the gopher tortoise (Gopherus polyphemus) has been characterized as both female defense and scramble-competition polygyny. Mating systems are typically not fixed and can be influenced by factors such as population density, demographic structure, and environmental conditions;, however, most populations will have a predominant strategy that results from local conditions. We assessed how male body size influences patterns of paternity and reproductive success in a natural population of gopher tortoises in Florida, USA. Using microsatellites, we assigned parentage of 220 hatchlings from 31 nests collected during two reproductive seasons. Larger males were significantly more likely to sire offspring and sired more offspring than smaller males; however, the likelihood of a clutch being multiply-sired was unrelated to male body size. We also found evidence of mate fidelity across years. Although paternity patterns in this high-density population are more consistent with defense polygyny, female monopoly by males was incomplete, with both large and small males contributing to multiply-sired clutches. Additional behavioral data are needed to clarify the role of female mate selection in paternity outcomes. The context-dependence of mating systems underscores the need to compare parentage patterns across populations and to recognize the potential for more than one strategy to be employed within a single population.

• Research Organization: Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)
• Sponsoring Organization: USDOE
• Contributing Organization: Archbold Biological Station; Cornell University; University of Georgia
• Grant/Contract Number: FC09-07SR22506
• OSTI ID: 1828596
• Alternate ID(s): OSTI ID: 1614659
• Journal Information: Journal of Heredity, Journal Name: Journal of Heredity Journal Issue: 7 Vol. 109; ISSN 0022-1503
• Publisher: American Genetic Association - Cambridge University Press
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Gopherus polyphemus
Reproductive strategies and kinship analysis
body size
mating system
microsatellites
reproductive success