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Locomotor Abilities (locomotor + ability)
Selected AbstractsGrass snakes exploit anthropogenic heat sources to overcome distributional limits imposed by oviparityFUNCTIONAL ECOLOGY, Issue 5 2010Kristin Löwenborg Summary 1.,A lack of warm nest-sites prevents oviparous reptile species from reproducing in cool climates; such areas are dominated by viviparous species because sun-seeking pregnant females can maintain high temperatures for their developing offspring. 2.,Our field and laboratory studies show that one oviparous species (the grass snake, Natrix natrix) escapes this cold-climate constraint (and hence, extends much further north in Europe than do other oviparous taxa) by ovipositing in a thermally distinctive man-made microhabitat (manure heaps on farms). 3.,In the field, temperatures inside manure heaps averaged 30·7 °C, much higher than compost heaps (20·6 °C) or potential natural nest-sites under logs and rocks (15·5 °C). 4.,In the laboratory, higher incubation temperatures not only hastened hatching, but also increased hatching success and modified the body sizes, colours, and locomotor abilities of hatchlings. Incubation temperatures typical of manure heaps (rather than alternative nest-sites) resulted in larger, faster offspring that hatched earlier in the season. 5.,Thus, anthropogenic activities have generated potential nest-sites offering thermal regimes not naturally available in the region; and grass snakes have exploited that opportunity to escape the thermal limits that restrict geographic distributions of other oviparous reptile taxa. [source] Terrestrial locomotion in sea snakes: the effects of sex and species on cliff-climbing ability in sea kraits (Serpentes, Elapidae, Laticauda)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2005X. BONNET Ecomorphological theory predicts a match between an organism's environment and its locomotor abilities, such that animals function most effectively under the conditions they experience in nature. However, amphibious species must simultaneously optimize performance in two different habitats posing incompatible demands on locomotor morphology and physiology. This situation may generate a mismatch between environment and locomotor function, with performance optimized only for the more important habitat type; alternatively, selection may fine-tune locomotor abilities for both types of challenges. Two species of sea kraits in New Caledonia offer an opportunity to examine this question: Laticauda laticaudata is more highly aquatic than L. colubrina, and males are more terrestrial than females within each taxon. We examined an aspect of locomotor performance that is critical to coming ashore on steep-walled rocky islets: the ability to climb steep cliffs. We also measured the muscular strength of these animals, a character that is likely critical to climbing performance. Laticauda colubrina was heavier-bodied and stronger (even relative to its body mass) than the more aquatic L. laticaudata; and within each species, males were heavier-bodied and stronger than females. The same patterns were evident in cliff-climbing ability. Thus, the ability of different species and sexes of sea kraits to climb steep cliffs correlates with their body shape even though these primarily aquatic animals use terrestrial habitats only rarely. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 433,441. [source] Heritability of anti-predatory traits: vigilance and locomotor performance in marmotsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2010D. T. BLUMSTEIN Abstract Animals must allocate some proportion of their time to detecting predators. In birds and mammals, such anti-predator vigilance has been well studied, and we know that it may be influenced by a variety of intrinsic and extrinsic factors. Despite hundreds of studies focusing on vigilance and suggestions that there are individual differences in vigilance, there have been no prior studies examining its heritability in the field. Here, we present one of the first reports of (additive) genetic variation in vigilance. Using a restricted maximum likelihood procedure, we found that, in yellow-bellied marmots (Marmota flaviventris), the heritability of locomotor ability (h2 = 0.21), and especially vigilance (h2 = 0.08), is low. These modest heritability estimates suggest great environmental variation or a history of directional selection eliminating genetic variation in these traits. We also found a significant phenotypic (rP = ,0.09 ± 0.04, P = 0.024) and a substantial, but not significant, genetic correlation (rA = ,0.57 ± 0.28, P = 0.082) between the two traits (slower animals are less vigilant while foraging). We found no evidence of differential survival or longevity associated with particular phenotypes of either trait. The genetic correlation may persist because of environmental heterogeneity and genotype-by-environment interactions maintaining the correlation, or because there are two ways to solve the problem of foraging in exposed areas: be very vigilant and rely on early detection coupled with speed to escape, or reduce vigilance to minimize time spent in an exposed location. Both strategies seem to be equally successful, and this ,locomotor ability-wariness' syndrome may therefore allow slow animals to compensate behaviourally for their impaired locomotor ability. [source] | ||||||||||