Literaturdatenbank
Literaturdatenbank |
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Rowe, J. W. (1992). Comparative life histories of the painted turtle (chrysemys picta) from western nebraska. Unpublished thesis , The University of Nebraska, Lincoln.
Added by: Sarina Wunderlich (30 Oct 2011 14:52:41 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Rowe1992b View all bibliographic details  |
Categories: General Keywords: Chrysemys, Chrysemys picta, Emydidae, Fortpflanzung = reproduction, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Rowe Publisher: The University of Nebraska (Lincoln) |
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| Abstract |
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Four western Nebraska populations of painted turtles (Chrysemys picta) were studied over a three year period to assess variation in reproductive strategies, growth and body size among local populations in a freshwater turtle. Relatively large clutches of small eggs and large average body size were characteristic of females from two large lakes compared to females in two smaller aquatic habitats. The latter females were smaller and produced relatively small clutches of large eggs. Relative clutch mass did not vary among sites. Growth curves suggested similar ages but different sizes at maturity among sites for both females and males. Generally, clutch size and mass as well as egg mass were positively correlated with maternal body size at all sites. Dry mass is more representative of material invested in reproduction because increases in egg wet mass occurred primarily from increases in water content. Eggs were more elongate (as opposed to spheroid) in populations with large relative egg mass and was a function of maternal body size. Clutch size and egg wet mass (but not dry mass) were negatively correlated in populations with large clutches of small eggs, consistent with optimal egg size models. Hatchling mass was positively correlated with egg wet mass in laboratory incubated eggs and varied among sites as expected from egg size distributions. Hatchling mass was significantly related to maternal carapace length in two populations. Total lipid content of eggs and post-embryonic yolks of hatchlings were similar among sites indicating that variation in parental investment among populations occurred by egg mass differences alone. These data suggest a life history in which the allocation of energy among offspring is based, at least in part, on growth conditions experienced by juveniles. Regardless of the population, it was apparently important that females begin reproducing after five or six activity seasons. Large relative egg mass (and hatchling mass) may occur when juvenile growth conditions are poor and when females are relatively small at first reproduction.
Added by: Sarina Wunderlich |