Literaturdatenbank
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Demuth, J. P. (2001). The effects of constant and fluctuating incubation temperatures on sex determination, growth, and performance in the tortoise gopherus polyphemus. Canadian Journal of Zoology, 79(9), 1609–1620.
Added by: Admin (17 Aug 2008 18:17:15 UTC) |
| Resource type: Journal Article BibTeX citation key: Demuth2001 View all bibliographic details  |
Categories: General Keywords: Gopherus, Gopherus polyphemus, Schildkröten = turtles + tortoises, Testudinidae, Zeitigung = incubation Creators: Demuth Collection: Canadian Journal of Zoology |
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| Abstract |
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Testudinidae Abstract: Temperature-dependent sex determination is one of the best documented yet evolutionarily enigmatic sex-determining systems. The classical theoretical framework suggests that temperature-dependent sex determination will be adaptive when males and females benefit differentially from development at certain temperatures. Empirical evidence has not provided convincing support for this "differential-fitness" hypothesis. Furthermore, since most experiments utilize constant temperature incubation treatments to explore phenotypic response to temperature, few studies have addressed the consequences of incubation under natural conditions. In this study I utilized constant-temperature laboratory incubations and natural-nest incubations to determine the effects of temperature on sex, size, growth, and locomotor performance in the tortoise Gopherus polyphemus. Constant-temperature incubations do induce substantial growth and performance variation in these tortoises. However, the data do not clearly support the differential-fitness hypothesis because (i) growth variation does not result in adult size dimorphism, (ii) performance differences are confined to a very short period after hatching, and (iii) natural incubation temperatures do not vary sufficiently to produce significant phenotypic variation in traits other than sex.
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