Raw data Tarentola substituta lab

Abstract
In small sedentary
ectotherms, patterns of spatial use result from the interplay between multiple,
often conflicting factors, including abiotic and biotic interactions.
Evaluating the costs and benefits of these pressures is crucial to make correct
behavioural decisions in terms of fitness. The insular São Vicente’s wall gecko Tarentola substituta provides a
relatively simple model system to study these questions as it inhabits arid
rocky habitats where refuges are limited, density of conspecifics is high, and
terrestrial predators are almost absent. In the field, adults tend to find
diurnal shelter under mid-sized rocks, frequently in male-female couples, while
juveniles occupy small rocks which are thermally suboptimal. A lab experiment
was conducted to determine the roles of ecological (shelter size and temperature)
and social (conspecifics) factors in refuge selection. Single and pair
combinations of geckos of different age and sex classes were allowed to select
among four refuges: cold small, hot small, cold large, or hot large rock. Based
on previous studies, we hypothesized that larger and thermally buffered rocks
would be the preferred refuges, and that adult male-female pairs under the same
rock would be more frequent than other combinations.

Geckos primarily selected larger shelters, trading off the presence of conspecifics against
thermal quality. In social terms, sex,
adult condition and size-related disparity shaped the patterns of aggregation, resulting
in lower aggregation frequencies between adults and juveniles and even between
juveniles of different sizes. These results reasonably match field observations
suggesting selection of rocks as diurnal retreats according to their thermal
properties, and social aggregations mainly involving adult males and females
but not juveniles. Overall, this combined evidence provides insights on the
spatial ecology of geckos, and likely other ectotherms, under conditions of low
predation, limited resources and high intraspecific competition, such as those
prevailing on island systems.