Microhabitat, diet, and reproductive activity of a population of the Andean shrew Cryptotis tamensis (Eulipotyphla: Soricidae)

Abstract

ABSTRACT The Tamá small-eared shrew is found in the Andean cloud forests of the Cordillera Oriental of Colombia and the Tamá paramo in western Venezuela. Few aspects of its biology are known, and all information comes from its original description. In a patch of oak cloud forest, we found a relatively abundant population of the species and studied its abundance, microhabitat preference, diet composition and reproductive features, and their relationship with the rainfall seasonality of the study area. The fieldwork was carried on for two years at altitudinal intervals from 2402 to 2627 m.a.s.l. We caught 44 shrews in microhabitats with dense vegetation cover, abundant litter and fallen trees; their abundance changed significantly through time, varying along with the precipitation of the month before the capture. We found seven groups of arthropods in their diet, the composition of which did not differ significantly between sexes, reproductive stages or seasons. These shrews have a specialised diet, with ants as the most important item. Reproductive males are distinguished externally by the presence of hypertrophic subcutaneous lateral glands. We found adult reproductive males and non-reproductive males throughout the duration of the study, and their abundance did not vary significantly with precipitation. In contrast, we did not capture females in the driest months of the years, and although adult non-reproductive females were also found, we found a significant relationship between the abundance of reproductive females and precipitation. Consequently, adult reproductive males would be a permanent reproductive resource for the females, which appear to adjust their reproductive activity during the rainy seasons.