Multiple paternity and breeding system in the gopher tortoise, Gopherus polyphemus.
ABSTRACT Little is known about the reproductive behaviors and the actual outcomes of mating attempts in the gopher tortoise (Gopherus polyphemus). We examined the mating system and reproductive behaviors of a population of gopher tortoises in central Florida. Using microsatellite markers, we assigned fathers to the offspring of seven clutches and determined that multiple fathers were present in two of the seven clutches examined. We found that gopher tortoises exhibited a promiscuous mating system with larger males fertilizing the majority of clutches. The advantage of larger males over smaller males in fertilizing females may be a result of larger males winning access to females in aggressive bouts with other males or larger males may be more attractive to females. Clutches produced by larger females tended to be sired by a single male, whereas clutches of smaller females tended to be sired by multiple males.
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ABSTRACT: We conducted a genetic study of the largest cluster of US federally threatened Gopher Tortoise (Gopherus polyphemus) colonies. Our objectives were to (1) identify genetic variation within and among colonies across the landscape; (2) determine which factors are important in affecting genetic variation, including land use, habitat quality, and population size; and (3) determine whether genetic partitioning among populations exists and how this relates to (a) geographic distance between sites, (b) Gopher Tortoise natural history and spatial ecology, and (c) land-use history. We studied genetic variability of nine microsatellite DNA loci for 340 adult tortoises from 34 colonies separated by 1.3-45.1 km across a 56,000-ha military installation. Overall genetic variation was low across the landscape and within colonies. Observed heterozygosity (H o ) of tortoise colonies was 49% and allelic richness was 52% of that found in populations located in the eastern portion of the species distribution where habitat is naturally more continuous. Our single colony with highest genetic variation had H o that was 57% and allelic richness that was 60% of eastern colonies. Genetic variation was greatest in sites with suitable habitat. We found weak to no genetic structure across the 45-km landscape (F St = 0.031; Dst = 0.006) and evidence for only one genetic group (K).Although landscape reconfiguration to create sites for military activity has redistributed tortoise colonies and home ranges, we concluded that weak population structure is natural across our study area. Comparison to similar results from a cluster of connected eastern colonies suggests this is a general characteristic of tortoises across large, continuous landscapes and that populations are composed of multiple colonies across the landscape and are naturally large in spatial extent. To alleviate the tortoise-human land use conflict on Camp Shelby, Mississippi, USA and to ensure these created areas continue to benefit tortoises in the long term, maintenance of forest habitat surrounding these created open areas is required. We recommend managing tortoises at Camp Shelby as one unit.Herpetologica 09/2011; 67:406-419. · 1.07 Impact Factor
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ABSTRACT: In polygynous species, males appear to gain additional offspring by pairing with multiple females simultaneously. However, this may not be true if some females copulate outside of the social pair bond. Polygynous males could experience lower paternity because of trade-offs among gaining multiple social mates, guarding fertility with these mates, and pursuing extra-pair matings. Alternatively, polygynous males could simultaneously gain extra social mates and have high paternity, either because of female preferences or because of male competitive attributes. We tested four predictions stemming from these hypotheses in a facultatively polygynous songbird, the dickcissel (Spiza americana). Unlike most previous studies, we found that males with higher social mating success (harem size) also tended to have higher within-pair paternity and that the number of extra-pair young a male sired increased significantly with his social mating success. Females that paired with mated males were not more likely to produce extra-pair young. In contrast, extra-pair paternity was significantly lower in the nests of females whose nesting activity overlapped that of another female on the same territory. This pattern of mating was robust to differences in breeding density. Indeed, breeding density had no effect on either extra-pair mating or on the association between polygyny and paternity. Finally, nest survival increased with harem size. This result, combined with the positive association between polygyny and paternity, contributed to significantly higher realized reproductive success by polygynous male dickcissels.Behavioral Ecology and Sociobiology 01/2013; 67(2). · 3.05 Impact Factor
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ABSTRACT: Molecular markers have proven to be a powerful tool for research on turtles. In particular, the application of the polymerase chain reaction (PCR) has increased the availability of molecular technologies while decreasing the cost. However, the cost, time, and expertise associated with developing and testing primers for a particular species can still present a significant barrier, especially to researchers less experienced with molecular methods. In this paper we provide the primer sequence, genomic location, and taxa for 202 PCR primers spanning the entire mitochondrial genome. We also report primers for 11 nuclear coding genes and introns. Finally, we provide primer sequence, amplicon size, and number of observed alleles for 181 microsatellite loci from all major clades of living turtles. We hope that this nearly comprehensive compilation of freshwater turtle and tortoise PCR primers can reduce some of the initial difficulties for beginning turtle geneticists and further facilitate research in existing labs. KEY W ORDS. - Reptilia; Testudines; turtle; PCR; primer; mtDNA; nuclear DNA; microsatellite; STR