doctoralThesis
Ecologia comportamental do lagarto Ameivula ocellifera (Squamata: Teiidae) em diferentes fitofisionomias do nordeste do Brasil
Fecha
2018-04-30Registro en:
SALES, Raul Fernandes Dantas de. Ecologia comportamental do lagarto Ameivula ocellifera (Squamata: Teiidae) em diferentes fitofisionomias do nordeste do Brasil. 2018. 137f. Tese (Doutorado em Psicobiologia) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2018.
Autor
Sales, Raul Fernandes Dantas de
Resumen
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.