Complementarity and efficiency of bat capture methods in a lowland tropical dry forest of Yucatán, Mexico

Bat-parasite interaction networks in urban green areas in northeastern Brazil

Interaction networks can provide detailed information regarding ecological systems, helping us understand how communities are organized and species are connected. The goals of this study were to identify the pattern of interaction between bats and ectoparasites in urban green areas of Grande Aracaju, Sergipe, and calculate connectance, specialization, nesting, modularity and centrality metrics. Bats were captured using 10 mist nets inside and on the edges of the fragments, and the collected ectoparasites were stored in 70% alcohol. All analyses were performed using R software. The interaction network consisted of 10 species of bats and 13 ectoparasites. Connectivity was considered low (0.12). The specialization indices for ectoparasites ranged from 0.50 to 1.00, and the value obtained for the network was 0.96, which is high. The observed nesting metric was low (wNODF = 1.47), whereas the modularity was high (wQ = 0.74), indicating that the studied network had a modular topology. All centrality metrics had low values. The observed modularity may have been caused by the evolutionary history of the bats and ectoparasites involved and the high specificity index of the interactions. The low centrality values may be associated with low connectivity and a high degree of specialization. This study provides relevant information on bat–parasite interactions in an urban environment, highlighting the need for further studies to improve our understanding of host–parasite interaction networks.

Are bat mist nets ideal for capturing bats? From ultrathin to bird nets, a field test

The use of mist nets is the most widespread technique to capture bats; however, no study has compared if the type of ground-level mist net used during sampling affects bat captures. We sampled bats using three different types of mist nets that varied in mesh (16, 18, and 20 mm) and denier/ply (45/1 and 75/2) sizes over 76 half-night surveys. We used 17–20 mist nets and checked them at intervals of 15–20 min. Capture rate for echolocating bats was higher in the two mist nets with the biggest denier/ply and smaller mesh sizes. “Ultrathin bat mist nets” showed the lowest capture rates (1.5 times less than “Regular bat mist nets”), whereas “Bird mist nets” had capture rates only 1.2 times smaller than “Regular bat mist nets.” Our results showed that “Bird mist nets” can sample echolocating bats almost as well as “Regular bat mist nets,” and that thinner mist nets may not be the best solution to capture bats that echolocate at high frequencies in this type of surveys. We highlight the importance of considering the efficiency, durability, and longevity of mist nets when choosing the ideal mist-net type for a bat survey.

Rapid survey of bats (Chiroptera) in the Atlantic Forest in eastern Sergipe, Brazil: unexpected diversity in a fragmented landscape

Despite advances in recent decades, the Atlantic Forest of northeastern Brazil is still one of the least studied regions of the country, regarding, for instance, the bat fauna. The present study reports on the results of a rapid survey of the bat fauna of a fragmented landscape in the Atlantic Forest of eastern Sergipe, in the legal forest reserve of Fazenda Santana, a commercial sugarcane plantation located in the adjoining municipalities of Japoatã and Pacatuba. We recorded 272 bats belonging to 23 species and four families, from which 265 individuals from 18 species from two families (Phyllostomidae and Vespertilionidae) were captured in the mist-nets, and seven individuals of six species from four families (Emballonuridae, Molossidae, Phyllostomidae and Vespertilionidae) were recorded during the active searches. This species richness was higher than that found in previous studies in the Atlantic Forest of northeastern Brazil. Lasiurus blossevillii and Micronycteris minuta were recorded in Sergipe for the first time, increasing to 57 the number of bat species known to occur in this state. The use of alternative strategies (such as active search and sampling one night per point, seeking to areas with greater availability of resources) in rapid surveys may contribute to the compilation of a more robust sampling, reinforcing the usefulness of this approach for the inventory of the bat fauna of a given region.