New records of disk-winged bats Thyroptera tricolor Spix, 1823 and T. devivoi Gregorin, Gonçalves, Lim & Engstrom, 2006 (Chiroptera: Thyropteridae) for the Brazilian Amazonia and Cerrado

We present new records for the disk-winged bats Thyroptera tricolor and T. devivoi in central and northern Brazil. Records of T. tricolor are from Aripuanã, Usina Hidrelétrica (UHE) Colíder (both in the northern Mato Grosso state) and Santana do Araguaia (southern Pará state). New records of T. devivoi are from a Cerrado area in the Rio Manso, Rio Quilombo (both in Mato Grosso state) and from an Amazon rainforest area at Juruti (Pará state). The records of Thyroptera devivoi for Pará and Mato Grosso are the first ones for these states and the records from the latter are based on two specimens previously identified as T. discifera. Based on the new identifications, we argue that T. discifera does not occur in the Cerrado.

Research on bats (Chiroptera) from the state of São Paulo, southeastern Brazil: annotated species list and bibliographic review

The state of São Paulo has a high number of mammal species, a great part of those is represented by bats. In this study I conducted historical review about the research on bats from the state of São Paulo and provide the first annotated species list and bibliographic review for the state. A total of 79 extant species belonging to eight families of bats occur in São Paulo. At least seven species are represented by fossils, two of these are extinct. I also present new records of rarely sampled species in the state such as Diaemus youngii, Diphylla ecaudata, Saccopteryx leptura, Thyroptera tricolor and Micronycteris microtis. Three species, Micronycteris brosseti, Mimon crenulatum and Uroderma bilobatum were removed from the list. Also is confirmed the occurrence of Histiotus montanus and Molossus aztecus in the state.

Repeatability in the contact calling system of Spix's disc-winged bat ( Thyroptera tricolor )

Spix's disc-winged bat ( Thyroptera tricolor ) forms cohesive groups despite using an extremely ephemeral roost, partly due to the use of two acoustic signals that help individuals locate roost sites and group members. While the calls that aid in group cohesion are commonly used, some bats rarely or never produce them. Here, we examine whether the differences observed in the contact calling behaviour of T. tricolor are repeatable; that is, whether individual differences are consistent. We recorded contact calls of individuals in the field and rates and patterns of vocalization. To determine whether measured variables were consistent within individuals, we estimated repeatability ( R ), which compares within-individual to among-individual variance in behavioural traits. Our results show that repeatability for call variables was moderate but significant, and that repeatability was highest for the average number of calls produced ( R =0.46–0.49). Our results demonstrate important individual differences in the contact calling behaviour of T. tricolor ; we discuss how these could be the result of mechanisms such as frequency-dependent selection that favour groups composed of individuals with diverse vocal strategies. Future work should address whether changes in social environment, specifically group membership and social status, affect vocal behaviour.

Sound amplification by means of a horn-like roosting structure in Spix's disc-winged bat

While sound is a signal modality widely used by many animals, it is very susceptible to attenuation, hampering effective long-distance communication. A strategy to minimize sound attenuation that has been historically used by humans is to use acoustic horns; to date, no other animal is known to use a similar structure to increase sound intensity. Here, we describe how the use of a roosting structure that resembles an acoustic horn (the tapered tubes that form when new leaves of plants such as Heliconia or Calathea species start to unfurl) increases sound amplification of the incoming and outgoing social calls used by Spix's disc-winged bat ( Thyroptera tricolor ) to locate roosts and group members. Our results indicate that incoming calls are significantly amplified as a result of sound waves being increasingly compressed as they move into the narrow end of the leaf. Outgoing calls were faintly amplified, probably as a result of increased sound directionality. Both types of call, however, experienced significant sound distortion, which might explain the patterns of signal recognition previously observed in behavioural experiments. Our study provides the first evidence of the potential role that a roost can play in facilitating acoustic communication in bats.

Riqueza de morcegos insetívoros em lagoas no Estado do Rio de Janeiro, Brasil

Amostragens de morcegos na região neotropical geralmente, contêm poucas espécies insetívoras. Apesar da elevada riqueza de morcegos insetívoros, o uso de rede de neblina resulta em baixa captura dessa guilda. As mais comumente amostradas no sudeste do Brasil são Molossus molossus, Molossus rufus e Myotis nigricans, mesmo representados por reduzido número de capturas são capturados próximos aos seus refúgios. Apesar de ser conhecida a preferência de espécies de morcegos insetívoros por ambientes ripários, poucos estudos têm explorado esses ambientes. O objetivo deste trabalho é analisar a riqueza de morcegos insetívoros em 31 lagoas no Estado do Rio de Janeiro usando redes de neblina. Em 1.995 horas de esforço de coleta, foram obtidas 2.159 capturas de 26 espécies exclusivamente ou parcialmente insetívoras. Oito espécies foram capturadas somente sobre as lagoas. A espécie mais frequente foi Myotis nigricans. Foi observado que as lagoas margeadas de florestas se mostraram ricas. A riqueza de espécies de morcegos nas lagoas não se diferenciou pela presença ou não de vegetação aquática e entre as lagoas salobras e doces. A amostragem em lagoas de tamanho médio ou grande e próximas a áreas residenciais podem ser as mais produtivas para a captura de espécies insetívoras. Três espécies amostradas são raramente citadas em inventários faunísticos: Macrophyllum macrophyllum, Lophostoma brasiliensis e Thyroptera tricolor. A realização de coletas com redes de neblina abertas sobre águas calmas foi mais representativa de morcegos insetívoros e pode resultar em uma melhor amostragem da assembleia de morcegos.

Mammalia, Chiroptera, Thyropteridae, Thyroptera tricolor Spix, 1823: distribution extension in Ecuador

In Ecuador, Thyroptera tricolor is distributed on the northern coastal region, in Amazonia, and in the foothills of the Andes between 50 to 1,800 m of altitude. We reported a capture of a non-breeding female at El Descanso, Los Ríos Province, in the central coastal region of Ecuador. With this record, we have extended the geographical distribution of T. tricolor in Ecuador 55 km further south. Using the available data for Ecuador, a predictive distribution model was generated using a Maximum Entropy approach.