Ecologia comportamental do lagarto Ameivula ocellifera (Squamata: Teiidae) em diferentes fitofisionomias do nordeste do Brasil

Abstract

The lizards of the family Teiidae are recognized as active foragers that maintain elevated body temperatures in activity, and do not defend territories, so that both males and females have opportunities to mate with several partners during the breeding season. However, there are few available studies that quantitatively analyzed the behavior of teiids, especially in South America. In this perspective, the purpose of this study was to investigate the foraging, thermoregulation and reproduction behaviors of the whiptail lizard Ameivula ocellifera, a conspicuous species widely distributed in the Northeastern region of Brazil, aiming to contribute to the knowledge about the behavioral ecology of South American teiids. The excursions for observations and field data collection were carried out in two seasons of the year (dry and rainy seasons) in three locations with distinct phytophysiognomies in the state of Rio Grande do Norte, two in the Caatinga domain (Lagoa Nova: mountainous Caatinga; Acari: Caatinga disturbed by agricultural activities) and one in the Atlantic Forest domain (Nísia Floresta: seasonal forest and coastal vegetation). To complement the analysis of reproductive behavior, data from two additional localities of Atlantic Forest (Natal) and Caatinga (Serra Negra do Norte) was used. The focal observations were recorded with a digital camcorder, and the videos were later analyzed by the continuous animal focal method. Some animals were captured after video records for analysis of diet and body temperatures. The diets of Caatinga populations were predominantly composed of termites (mountainous Caatunga) and insect larvae (disturbed Caatinga), while the Atlantic Forest population presented a more generalized diet. The foraging behavior was characterized by high indices of movement and active search for prey, but the Atlantic Forest population presented a lower rate of active search in relation to the two Caatinga populations, and seasonal differences occurred in the mountainous Caatinga population. There were also differences in the main mode of prey discovery among the Atlantic Forest population (visual and chemosensory search while moving) and Caatinga populations (digging the substrate). Behavioral adjustments in response to changes in prey availability and differences in vigilance time against predators are plausible explanations for seasonal and population differences in foraging behavior. The active body temperatures (TC) varied between 32.4 and 43.4 °C, with similar mean values among the three populations, in the range of 38-39 °C. Despite the similarity in TC, lower values of substrate (TS) and air temperatures (TA) were recorded for the mountainous Caatinga. When comparing the three populations during the rainy season, it was verified that animals from mountainous Caatinga spent more time in the sun and less time in the shade than the other two populations. In addition, TS and TA varied seasonally in the mountainous Caatinga, with lower values in the rainy season, and animals in this area spent more time exposed to the sun and less time exposed to filtered sun in the rainy season than in the dry season. A positive relationship was observed in the three populations between the time exposed to cloudy conditions and basking time, and lizards from disturbed Caatinga spent more time basking in comparison to the other two populations. These results suggest that the maintenance of similar TC between populations and throughout the year in Lagoa Nova occurred due to flexibilities in thermoregulatory behavior. The mating system of A. ocellifera is characterized by consensual copulations preceded by male courtship, and post-copulatory accompaniment of the female, with the male companion repelling rival males, and guarding the entrance to the female's burrow when she finishes daily activity. Additionally, some males may copulate opportunistically with a female without previous courtship. The accompaniment has survival costs for males, as they spent more time in vigilance, less time performing active search for prey, captured less prey, and initiated 75% more agonistic interactions against other males when compared to solitary males. Females can benefit from post-copulatory courtship and access to high-quality males. Opportunistic copulations, on the other hand, may be a conditional strategy adopted by less dominant males to achieve mating.