Literaturdatenbank
Literaturdatenbank |
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McGuire, J. M. (2011). Comparative analysis of factors influencing male reproductive success in sympatric freshwater turtles. Unpublished thesis , Michigan State University.
Added by: Sarina Wunderlich (18 Nov 2012 17:43:44 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: McGuire2011a View all bibliographic details  |
Categories: General Keywords: Chelydra, Chelydra serpentina, Chelydridae, Chrysemys, Chrysemys picta, Emydidae, Emydoidea, Emydoidea blandingii, Fortpflanzung = reproduction, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: McGuire Publisher: Michigan State University |
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| Abstract |
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Male reproductive success (RS) is primarily constrained by mate number. However, when females vary in reproductive quality (i.e., reproductive frequency, clutch size, egg size), female quality can contribute substantially to male reproductive success. I used a comparative inter-specific approach, to document sources of variation in male reproductive success in three species of freshwater turtles (Painted turtles (Chrysemys picta), Blanding's turtles (Emydoidea blandingii) and Snapping turtles (Chelydra serpentina). Data were collected and analyzed using extensive background information from a long-term study on the life history and demography of all three species. Long-term studies (1953-2007) on the E.S. George Reserve in Michigan allowed analyses to be preformed based on females of known age, size, and reproductive history. In all three species, larger and older females were of higher reproductive quality than were smaller or younger females, suggesting that males would benefit by mating with these females compared to mating indiscriminately. Using multi-locus microsatellite genotypes and paternity analysis, I examined offspring (Painted turtles N = 1065 from 171 clutches; Blanding's turtles N = 772 from 98 clutches, Snapping turtles N = 1064 from 63 clutches) collected over four years (Painted and Snapping turtles) and 8 years (Blanding's turtles) from nests of known females. Incidence of multiple paternity was variable among years in all three species (Painted turtles, 6.1% - 30.0%; Blanding‟s turtles, 15.4% - 55.6%; Snapping turtles, 44.4% - 61.5%) and was positively associated with female age in all three species. Sperm from the same male(s) fertilized successive clutches (repeat paternity) among years in all three species. Reproductive frequency contributed substantially to male reproductive success. Paternity analyses conducted in Painted and Blanding's turtles revealed that the number of clutches sired represented a significant component to male reproductive success. Mate number was not a substantial source of variation of male reproductive success in Painted turtles, as few males mated with more than one female. In Blanding's turtles mate number and clutch number were significantly associated with male reproductive success. Female reproductive frequency increased with increasing age,. Additionally, older females are more likely to have multiple males sire offspring within a clutch suggesting that older females were comparatively more attractive to males or more receptive to mating attempts by multiple males. Clutches of eggs from older females were more genetically diverse (lower coancestry) that clutches of younger females. Therefore, older females contribute disproportionally to population levels of genetic diversity. For species such as Blanding's turtles that make extensive use of terrestrial habitats, we found that older females were more likely to have offspring sired by males from other residence wetlands than do younger females. Results highlight the need to protect corridors that facilitate movement and gene flow among permanent wetlands. The presence of age-specific effects on female reproductive quality in all three species highlight the importance of management strategies that reduce adult mortality
Added by: Sarina Wunderlich |