Description of the echolocation pulses of insectivorous bats with new records for southwest Colombia

Abstract

Diversity surveys may be performed by different sampling methods. In the case of bats, the use of traditional methods such as mist nets, harp traps, and roost detection have limitations in widely covering the diversity in a landscape. Most registered species are restricted to species that forage at the undergrowth or in enclosed spaces. However, acoustic monitoring is complementary to conventional methods and can help obtain more complete bat inventories while avoiding alterations in usual foraging activities and disruption in their life cycles. This study describes the acoustic parameters (spectral and temporal variables) of the echolocation pulses of insectivorous bats to characterise acoustically different species of bats present in southwest Colombia. We recorded echolocation calls between December 2017 and May 2020 in the Andean and Pacific regions of the department of Nariño. A total of 81 sequences from free-flying bats were analysed from eight species belonging to three families: Vespertilionidae, Molossidae and Emballonuridae. Myotis riparius and Lasiurus blossevillii were registered for the first time in Nariño Department. The species M. albescens, M. keaysi, M. riparius and L. blossevillii (Vespertilionidae) had pulses of frequency modulated with a quasi-constant ending; Molossus molossus, Tadarida brasiliensis and Promops centralis (Molossidae) had pulses with constant and quasi-constant frequencies; and Saccopteryx bilineata (Emballonuridae) had pulses with quasi-constant frequencies. This study enriches the efforts to solve acoustic species classification issues of insectivorous bats in the Neotropics.