RESUMEN
We investigated how the potential distribution of Histiotus velatus is affected by the addition of new records over decades (decade effect). Assuming that (1: hypothesis of the effect of the decade) the addition of new occurrence records over time increases the potential size of the species distribution; and (2: Wallacean distance hypothesis) over the years, the new points added are increasingly distant from the research centers. Considering the geographic knowledge gap of this species, our objective is to report a new record of this species and estimate its potential distribution in South America through environment niche models (ENMs). For this, we compiled records of occurrence of species, selected from 1900 to 2015. We used 19 bioclimatic variables available in the WorldClim database to estimate the potential distribution of the species, and we used three modeling algorithms: Maximum Entropy (MXT), Random Forest (RDF), and Support Vector Machine. To test the Wallacean distance hypothesis, we calculated the Euclidian distance from occurrences to bat research centers in Brazil, located using a national researchers' information dataset ("Plataforma Lattes"). To test the hypothesis of the decade effect, we used the beta regression analysis, taking conservative and non-conservative approaches. The results showed that the predicted area expanded and retracted with the addition of new occurrences over the decades, with an improvement in the accuracy of models. Most records are located in the southeastern region of Brazil, but algorithms predicted areas in regions where there are no records. Only the conservative approach has had a positive relationship over the decades. The distance from new points does not increase over the years of research centers.
RESUMEN
Bats of the genus Artibeus are among the most important seed dispersers in early successional forests. We report observations on the foraging behavior of Artibeus lituratus in Pedra da Cebola Municipal Park, an urban park in the city of Vitória, Espírito Santo, southeastern Brazil. Observations were made during six consecutive days (April 1st to April 6th, 2006). Three mist-nets were opened each night close to a Maclura tinctoria tree (Moraceae), remaining open from 18:00 to 22:00, totaling four hours per night, and 24 hours of sampling effort. We observed two peaks of feeding activity at the tree, one between 18:20 and 19:30, and a second one at 21:00. This is the first observation of Artibeus lituratus feeding on M. tinctoria fruits, therefore adding a new item to the known diet of the species. M. tinctoria fruits have large seeds that are not swallowed by bats, they consume the fruit pulp and discard the seeds. A diet of fruits with large seeds may indicate an important resource not detected in dietary studies based on fecal samples, but better detected by direct observation or by studying feeding roosts. It is important to use different sampling techniques in dietary studies since they complement each other and, together, provide a better knowledge on the diet of bats.
Morcegos do gênero Artibeus estão entre os mais importantes dispersores de sementes em florestas em estágios iniciais de sucessão. Aqui descrevemos observações sobre o comportamento de forrageio de Artibeus lituratus no Parque Municipal da Pedra da Cebola, um parque urbano na cidade de Vitória, Espírito Santo, sudeste do Brasil. As observações foram feitas durante seis dias consecutivos (01 a 06 de Abril de 2006). Três redes de neblina foram abertas cada noite, próximas a uma árvore de Maclura tinctoria, Moraceae, permanecendo abertas das 18:00 às 22:00 horas, totalizando quatro horas por noite, e 24 horas de esforço amostral. Foram observados dois picos de atividade de forrageio, o primeiro entre 18:20 e 19:30 horas, e o segundo às 21:00 horas. Este é o primeiro registro de consumo de frutos de M. tinctoria por A. lituratus, adicionando mais um ítem para a dieta conhecida desta espécie. Os frutos de M. tinctoria possuem sementes de tamanho relativamente grande, que não são ingeridas pelos morcegos. Eles consomem a polpa dos frutos e descartam as sementes. Uma dieta de frutos com sementes grandes pode indicar um recurso importante que não é detectado em estudos de dieta baseados apenas na análise de fezes, e que será detectado apenas por observação direta ou através do estudo de sítios de alimentação. O uso de técnicas de amostragem variadas em estudos de dieta é de extrema importância, pois elas complementam umas às outras, e em conjunto nos fornecem informações melhores e mais precisas sobre a dieta de morcegos do que qualquer uma delas forneceria isoladamente.