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Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards

It is generally assumed that favourable weather conditions determine the activity levels of lizards, because of their temperature-dependent behavioural performance. Inactivity, however, might have a selective advantage over activity, as it could increase survival by reducing exposure to predators. C...

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Autores principales: Broeckhoven, Chris, Mouton, Pieter le Fras Nortier
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580596/
https://www.ncbi.nlm.nih.gov/pubmed/26397831
http://dx.doi.org/10.1371/journal.pone.0137428
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author Broeckhoven, Chris
Mouton, Pieter le Fras Nortier
author_facet Broeckhoven, Chris
Mouton, Pieter le Fras Nortier
author_sort Broeckhoven, Chris
collection PubMed
description It is generally assumed that favourable weather conditions determine the activity levels of lizards, because of their temperature-dependent behavioural performance. Inactivity, however, might have a selective advantage over activity, as it could increase survival by reducing exposure to predators. Consequently, the effects of weather conditions on the activity patterns of lizards should be strongly influenced by the presence of predators. Using remote camera traps, we test the hypothesis that predator presence and weather conditions interact to modulate daily activity levels in two sedentary cordylid lizards, Karusasaurus polyzonus and Ouroborus cataphractus. While both species are closely related and have a fully overlapping distribution, the former is a fast-moving lightly armoured lizard, whereas the latter is a slow-moving heavily armoured lizard. The significant interspecific difference in antipredator morphology and consequently differential vulnerability to aerial and terrestrial predators, allowed us to unravel the effects of predation risk and weather conditions on activity levels. Our results demonstrate that K. polyzonus is predominantly active during summer, when ambient temperatures are favourable enough to permit activity. In contrast, a peak in activity during spring was observed in O. cataphractus, with individuals being inactive during most of summer. While favourable weather conditions had a strong effect on the activity levels of K. polyzonus, no such relationship was present in O. cataphractus. Contrary to our hypothesis, the presence of terrestrial predators does not seem to affect daily activity levels or alter the influence of weather conditions on activity levels. We conclude that inactivity in O. cataphractus appears to be related to seasonal differences in vulnerability to predators, rather than the presence of predators, and highlight the importance of additional selective pressures, such as food abundance, in determining the species’ activity levels.
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spelling pubmed-45805962015-10-01 Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards Broeckhoven, Chris Mouton, Pieter le Fras Nortier PLoS One Research Article It is generally assumed that favourable weather conditions determine the activity levels of lizards, because of their temperature-dependent behavioural performance. Inactivity, however, might have a selective advantage over activity, as it could increase survival by reducing exposure to predators. Consequently, the effects of weather conditions on the activity patterns of lizards should be strongly influenced by the presence of predators. Using remote camera traps, we test the hypothesis that predator presence and weather conditions interact to modulate daily activity levels in two sedentary cordylid lizards, Karusasaurus polyzonus and Ouroborus cataphractus. While both species are closely related and have a fully overlapping distribution, the former is a fast-moving lightly armoured lizard, whereas the latter is a slow-moving heavily armoured lizard. The significant interspecific difference in antipredator morphology and consequently differential vulnerability to aerial and terrestrial predators, allowed us to unravel the effects of predation risk and weather conditions on activity levels. Our results demonstrate that K. polyzonus is predominantly active during summer, when ambient temperatures are favourable enough to permit activity. In contrast, a peak in activity during spring was observed in O. cataphractus, with individuals being inactive during most of summer. While favourable weather conditions had a strong effect on the activity levels of K. polyzonus, no such relationship was present in O. cataphractus. Contrary to our hypothesis, the presence of terrestrial predators does not seem to affect daily activity levels or alter the influence of weather conditions on activity levels. We conclude that inactivity in O. cataphractus appears to be related to seasonal differences in vulnerability to predators, rather than the presence of predators, and highlight the importance of additional selective pressures, such as food abundance, in determining the species’ activity levels. Public Library of Science 2015-09-23 /pmc/articles/PMC4580596/ /pubmed/26397831 http://dx.doi.org/10.1371/journal.pone.0137428 Text en © 2015 Broeckhoven, Mouton http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Broeckhoven, Chris
Mouton, Pieter le Fras Nortier
Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title_full Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title_fullStr Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title_full_unstemmed Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title_short Some Like It Hot: Camera Traps Unravel the Effects of Weather Conditions and Predator Presence on the Activity Levels of Two Lizards
title_sort some like it hot: camera traps unravel the effects of weather conditions and predator presence on the activity levels of two lizards
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580596/
https://www.ncbi.nlm.nih.gov/pubmed/26397831
http://dx.doi.org/10.1371/journal.pone.0137428
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