seasonal distribution and circadian activity in the troglophile long-footed robber frog, eleutherodactylus longipes (anura: brachycephalidae) at los riscos cave, queretaro, mexico: field and laboratory studies

Abstract

Los Riscos Cave belongs to the El Abra limestone and its geographical location is in the Sierra Gorda in the State of Queretaro, Mexico. The cave has a high faunal diversity that includes arthropods and some vertebrates, such as vampire bats and anurans, and includes the robber frog Eleutherodactylus longipes (Baird, 1859). The abundance of the robber frog changes non-randomly between dry and rainy seasons and is related to the search for humid conditions inside the cave. In addition, the robber frog was located in areas where some scattered light may influence its dispersion inside the cave

and therefore, its activity. Frogs displayed spontaneous circadian rhythms of locomotor activity from the first days of the experimental observation in constant darkness. The average period of circadian rhythms was 24.85 +/- 0.93 h indicating, in isolated conditions, a diurnal activity. When exposed to artificial light-dark cycles, the animals lacked daily activity rhythms, and ultradian activity was observed. The preference for high humidity and low illumination in the cave and a partial endogenous circadian rhythmicity confirm the troglophilic affinity of the robber frog to cave environments.