Literaturdatenbank
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Escalona, T., Valenzuela, N., & Adams, D. C. , Do egg-laying females lacking parental care adaptively manipulate their offspring phenotype and consequent fitness via active nest-site selection? Paper presented at Turtle Survival Alliance 2007 Annual Meeting.
Added by: Admin (13 Dec 2008 22:23:39 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Escalona2007 View all bibliographic details  |
Categories: General Keywords: Fortpflanzung = reproduction, Habitat = habitat, Podocnemididae, Podocnemis, Podocnemis unifilis, Schildkröten = turtles + tortoises, Südamerika = South America, Zeitigung = incubation Creators: Adams, Escalona, Valenzuela Collection: Turtle Survival Alliance 2007 Annual Meeting |
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| Abstract |
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In egg-laying organisms that lack parental care, female nest-site choice has important consequences on offspring phenotype and fitness, especially in species with temperature-dependent sex determination (TSD) because of its effect on sex ratio evolution. This has led some to propose nest-site selection (NSS) as a potential mechanism for females to adaptively manipulate offspring sex ratio and fitness in TSD taxa. Empirical tests of such adaptive hypotheses have relied on identifying non-random nesting patterns and most analyses are limited to the scale of a single site or season. However, the crucial prediction of NSS, that patterns emerging from adaptive female nest-site choice for sex ratio or fitness manipulation must be repeatable across space and time to be the target of selection is typically not examined. This is critical, as other mechanisms (such as social facilitation), can produce similar non-random nesting patterns. Here we examined the nesting patterns of Podocnemis unifilis turtles at multiple spatiotemporal scales and tested between the two alternative hypotheses (NSS and social facilitation). We detected non-random spatial and environmental nesting patterns within beaches and years, but patterns were unpredictably variable among beaches and years. In addition, patterns of nest laying timing and predation rates were consistent with social facilitation. Thus, our findings are incompatible with adaptive maternal nest-site choice hypothesis, but support the social facilitation hypothesis. We propose that social facilitation warrants direct testing in other TSD taxa by the use of similar multiple spatiotemporal scales before invoking adaptive female nest-site choice for sex ratio or fitness manipulation.
Added by: Admin |