Comparing the efficiency of monofilament and regular nets for capturing bats

Abstract

Regular nylon or polyester mist nets used for capturing bats have several drawbacks, particularly that they are inefficient at sampling insectivorous species. One possible alternative is to use monofilament nets, whose netting is made of single strands of yarn instead of several as regular nets, making them less detectable. To date, only one study has quantified the differences in capture rates between monofilament and regular mist nets for the study of bats, yet surprisingly, its findings suggest that the latter are more efficient than the former. Here, we provide further evidence of the differences in sampling efficiency between these two nets. We captured 90 individuals and 14 species in regular nets and 125 individuals and 20 species in monofilament nets. The use of monofilament nets increased overall capture rates, particularly for insectivorous species. Species accumulation curves indicate that samples based on regular nets are significantly underestimating species diversity, most notably as these nets fail at sampling rare species. We show that incorporating monofilament nets into bat studies offers an opportunity to expand records of different guilds and rare bat species and to improve our understanding of poorly known bat assemblages while using a popular, relatively cheap and portable sampling method.

Exceptionally Uniform Bat Assemblages across Different Forest Habitats Are Dominated by Single Hyperabundant Generalist Species

“…Some of the differences revealed via mist netting at water bodies hardly apply to mist netting on commuting routes, like forest roads, however. The increased popularity of monofilament (ultra-thin) mist nets, replacing the thicker polyester or nylon nets that were predominant in earlier studies, may partially reduce bias in capture data and allow the capture of even those insectivorous bats with the highest sonar resolution [60]. In our study, the application of monofilament nets allowed us to effectively sample even M. nattereri, the species adapted to the smallest target range resolution among the representatives of the genus Myotis and, as a result, able to effectively navigate even a few centimeters from obstacles [61].…”

Conocimiento histórico y distribución geográfica potencial del murciélago mastín azteca (Molossidae: Molossus aztecus) en Norteamérica

“…Además, los murciélagos insectívoros suelen tener una ecolocación precisa, lo que les facilita la detección de las redes de niebla en comparación con otras especies de murciélagos (Meyer et al, 2011). Los métodos indirectos como las fototrampas y equipos de registro acústico han enriquecido el conocimiento de aquellas especies más elusivas (Chaves-Ramírez et al, 2021;Tremlett et al, 2020).…”