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Universidade Federal Rural do Semi-Árido (UFERSA) 2021

Onde a luz da lua não importa : atividade do lagarto noturno Hemidactylus agrius ao longo do ciclo lunar em florestas tropicais sazonalmente secas

Rossetti Neto, Francisco de Oliveira

Titre : Onde a luz da lua não importa : atividade do lagarto noturno Hemidactylus agrius ao longo do ciclo lunar em florestas tropicais sazonalmente secas

Auteur : Rossetti Neto, Francisco de Oliveira

Université de soutenance : Universidade Federal Rural do Semi-Árido (UFERSA)

Grade : Mestrado em Ecologia e Conservação 2021

Résumé
The lunar cycle influences the behavior of many nocturnal animals. Some species increase (lunar philia) and others decrease (lunar phobia) their activity levels on clearer nights, and generally, nocturnal scaly reptiles (Squamata) exhibit lunar-phobic behavior, seeking to avoid predators primarily guided by vision. However, most studies on lunar influence on lizard and snake activity have been carried out with species from desert environments and, therefore, it is not known which pattern occurs in climatically less extreme and structurally more complex environments, such as Seasonally Dry Tropical Forests. In this sense, we investigated how nocturnal lizards from the Brazilian semiarid region are influenced by the lunar cycle, using the lizard Hemidactylus agrius as a model, a species with wide distribution in the Caatinga domain and with high local abundance. We tested the hypothesis most supported by the literature, that the activity of nocturnal scaly reptiles would be negatively influenced by the luminosity reflected by the moon, hoping to find a greater number of active individuals during the darkest nights. Lizard activity was measured using time-limited active searches in three seasonally dry tropical forest areas, in the municipalities of Assú and Mossoró in the state of Rio Grande do Norte and in the municipality of Russas in the state of Ceará. In all, we recorded 113 active H. agrius individuals over 64 active searches (270.4 person-hours of sampling effort). Our results revealed that individuals of H. agrius were active regardless of the percentage illuminated by the lunar face and the amount of light reflected by the moon reaching the ground, not corroborating the hypothesis of lunar phobia. The observed pattern of activity, varying independently of the lunar cycle, can be explained by extrinsic processes (structural complexity of the vegetation and predator foraging strategy) and intrinsic processes of the target species (high visual acuity and general eating habits), which can act together or alone. If, on the one hand, the vegetation complexity of dry forests can provide adequate conditions for H. agrius activity even on clearer nights, the predatory pressure exerted by predators primarily oriented by chemical signals, such as snakes and arthropods, can compromise a greater activity of H. agrius on darker nights. Our findings contribute to the understanding of the influence of light reflected by the moon on the activity of nocturnal lizards, revealing that in the Seasonally Dry Tropical Forests of the Brazilian semiarid region, the activity of H. agrius does not follow the expected pattern of lunar phobia

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Page publiée le 21 décembre 2022