One solution for two challenges: the lizard Microlophus atacamensis avoids overheating by foraging in intertidal shores.
In lizards, one of the most important behavioral mechanisms to cope with spatial and temporal variations in thermal resources observed is activity time. The longer a lizard can maintain activity, the more time it has to forage and reach larger adult body size. We studied the behavioral adjustments to different climatic regimens on daily and seasonal scales in three natural populations of the lizard Microlophus atacamensis along a latitudinal temperature and rainfall gradient. We also used Niche Mapper to determinate the amount of thermally suitable time for activity for this species. Abundance and daily activity patterns varied greatly over the year for the three populations. In summer and spring, the daily activity times were greater, and were reduced in fall and winter seasons. In summer, when stressful heat loads should prohibit activity over a midday gap, lizards did not show bimodal patterns of activity. Instead, they move to the cooler intertidal habitat. Abundance and thermal quality in the southernmost coolest site was lower, and the potential annual activity time decreases with latitude. Contrary to expectations, lizards from this locality showed the largest body sizes possibly due to diet and/or time to sexual maturation. Our results indicate that the intertidal habitat is a key factor that influences daily and seasonal activity of M. atacamensis lizards. While this habitat is not climatically optimal for lizards, it allows them to behaviorally extend their activity window and gain access to food in the intertidal areas.
Centro de Investigación y Gestión en Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
Maritza
M
Sepúlveda
Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Pablo
P
Sabat
Department of Zoology, University of Wisconsin, Madison, Wisconsin, United States of America.
Warren P
WP
Porter
Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America.
José Miguel
JM
Fariña
D000704:Analysis of Variance; D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology*; D049628:Body Size; D001833:Body Temperature Regulation / Q000502:physiology*; D002677:Chile; D002980:Climate; D005247:Feeding Behavior / Q000502:physiology*; D008116:Lizards / Q000502:physiology*; D012621:Seasons; D013997:Time Factors