Ludmilla Moura de Souza Aguiar

Habitat use and movements of Glossophaga soricina and Lonchophylla dekeyseri (Chiroptera : Phyllostomidae) in a Neotropical savannah

The greatest current threat to terrestrial fauna is continuous and severe landscape modification that destroys and degrades animal habitats. This rapid and severe modification has threatened species, local biological communities, and the ecological services that they provide, such as seed dispersal, insect predation, and pollination. Bats are important pollinators of the Cerrado (woodland savanna) because of their role in the life cycles of many plant species. However, there is little information about how these bat species are being affected by habitat loss and fragmentation. We used radio-tracking to estimate the home ranges of Glossophaga soricina (Pallas, 1776) and Lonchophylla dekeyseri Taddei, Vizotto & Sazima, 1983. The home range of G. soricina varies from 430 to 890 ha. They combine shortrange flights of up to 500 m to nearby areas with longer flights of 2 to 3 km that take them away from their core areas. The maximum flight distance tracked for L. dekeyseri was 3.8 km, and its home range varies from 564 to 640 ha. The average distance travelled by this species was 1.3 km. Our data suggest that G. soricina and L. dekeyseri are able to explore the fragmented landscape of the Central Brazilian Cerrado and that they are likely to survive in the short- to medium-term. The natural dispersal ability of these two species may enable them to compensate for continued human disturbance in the region.

Bats from Fazenda Intervales, Southeastern Brazil: species account and comparison between different sampling methods

Assessing the composition of an areas bat fauna is typically accomplished by using captures or by monitoring echolocation calls with bat detectors. The two methods may not provide the same data regarding species composition. Mist nets and harp traps may be biased towards sampling low flying species, and bat detectors biased towards detecting high intensity echolocators. A comparison of the bat fauna of Fazenda Intervales, southeastern Brazil, as revealed by mist nets and harp trap captures, checking roosts and by monitoring echolocation calls of flying bats illustrates this point. A total of 17 species of bats was sampled. Fourteen bat species were captured and the echolocation calls of 12 species were recorded, three of them not revealed by mist nets or harp traps. The different sampling methods provided different pictures of the bat fauna. Phyllostomid bats dominated the catches in mist nets, but in the field their echolocation calls were never detected. No single sampling approach provided a complete assessment of the bat fauna in the study area. In general, bats producing low intensity echolocation calls, such as phyllostomids, are more easily assessed by netting, and bats producing high intensity echolocation calls are better surveyed by bat detectors. The results demonstrate that a combined and varied approach to sampling is required for a complete assessment of the bat fauna of an area.

The diet of bats from Southeastern Brazil: the relation to echolocation and foraging behaviour

In this study the incidence of moths and beetles was examined from feces samples of bats that use different foraging behaviors. Twenty sites around the Fazenda Intervales, a Field Research Station located in Sao Paulo State, in southeastern Brazil were sampled. Feces were collected from bats caught in mist nets, Turtle Traps or hand nets and, in one case, from beneath a roost. Feces samples were taken from six species of bats: Micronycteris megalotis (Gray, 1842), Mimon bennettii (Gray, 1838), Furipterus horrens (F. Cuvier, 1828), Myotis riparius Handley, 1960, Myotis ruber (E. Geoffroy, 1806) and Histiotus velalus (I. Geoffroy, 1824). To record and describe the frequencies dominating bat echolocation calls, an Anabat II bat detector coupled with an Anabat ZCA interfaces and DOS laptop computers were used. The data show that Furipterus horrens feeds extensively on moths, as predicted from the features of its echolocation calls. Gleaning bats, whose echolocation calls are much less conspicuous to moths take a wide range of insect (and other) prey.

Descriptive ecology of bat flies (Diptera: Hippoboscoidea) associated with vampire bats (Chiroptera: Phyllostomidae) in the cerrado of Central Brazil.

We studied the ectoparasitic bat flies of three phyllostomid vampire bat species. Bats were collected monthly from April 2004-March 2005 in caves within the Cafuringa Environmental Protection Area in the Federal District of Brazil. A total of 1,259 specimens from six species in the Streblidae family were collected from 332 bats. High host affinity from the sampled bat fly species and high prevalence of bat flies confirms the primary fly-host associations (Strebla wiedemanni, Trichobius parasiticus and Trichobius furmani with Desmodus, Trichobius diaemi and Strebla diaemi with Diaemus and T. furmani with Diphylla). Male flies outnumbered females in several associations. Some of the observed associations (e.g., Strebla mirabilis with Desmodus and S. mirabilis, Trichobius uniformis and S. wiedemanni with Diphylla) were inconclusive and the causes of the associations were unclear. There are several explanations for these associations, including (i) accidental contamination during sampling, (ii) simultaneous capture of several host species in the same net or (iii) genuine, but rare, ecological associations. Although various species of vampire bats share roosts, have similar feeding habits and are close phylogenetic relatives, they generally do not share ectoparasitic streblid bat flies. T. diaemi and S. diaemi associations with Diaemus youngi have not been previously reported in this region.

Do Current Vampire Bat (Desmodus rotundus) Population Control Practices Pose a Threat to Dekeyser's Nectar Bat's (Lonchophylla dekeyseri) Long-Term Persistence in the Cerrado?

The Cerrado is rapidly losing space to agriculture, pastures and urbanization. Current management practices to control rabies outbreaks through the eradication of vampire bat populations may put other bat species in peril. Our objective is to evaluate if the current vampire bat population control practices could pose a threat to Lonchophylla dekeyseris persistence, an endemic bat of the Cerrado. We used the VORTEX program to model different vampire bat management scenarios, causing low (25%), medium (50%) or high (75%) incidental mortality to L. dekeyseri populations. Inbreeding depression has been identified as a threat to the species, therefore we also modeled scenarios evaluating such effects. Results show that current vampire bat management practices have serious impacts on populations of L. dekeyseri. In all cases marked declines in population sizes were observed (even when there was no decline in survival probabilities). For medium and high incidental mortality management scenarios, we also observed decreases in survival probability and in genetic diversity. In those scenarios evaluating vampire bat management and inbreeding depression together, the models suggest that such interaction results in more pronounced declines. Habitat loss and fragmentation in the Cerrado are severe threats and have already negatively impacted L. dekeyseri. Unfortunately, if currentpopulation control practices dealing with vampire bats are not changed, inappropriate rabies management may be the coup de grace to the long-term persistence of this species.

Carcass persistence and detectability: reducing the uncertainty surrounding wildlife-vehicle collision surveys

Carcass persistence time and detectability are two main sources of uncertainty on roadkill surveys. In this study, we evaluate the influence of these uncertainties on roadkill surveys and estimates. To estimate carcass persistence time, three observers (including the driver) surveyed 114km by car on a monthly basis for two years, searching for wildlife-vehicle collisions (WVC). Each survey consisted of five consecutive days. To estimate carcass detectability, we randomly selected stretches of 500m to be also surveyed on foot by two other observers (total 292 walked stretches, 146 km walked). We expected that body size of the carcass, road type, presence of scavengers and weather conditions to be the main drivers influencing the carcass persistence times, but their relative importance was unknown. We also expected detectability to be highly dependent on body size. Overall, we recorded low median persistence times (one day) and low detectability (<10%) for all vertebrates. The results indicate that body size and landscape cover (as a surrogate of scavengers’ presence) are the major drivers of carcass persistence. Detectability was lower for animals with body mass less than 100g when compared to carcass with higher body mass. We estimated that our recorded mortality rates underestimated actual values of mortality by 2–10 fold. Although persistence times were similar to previous studies, the detectability rates here described are very different from previous studies. The results suggest that detectability is the main source of bias across WVC studies. Therefore, more than persistence times, studies should carefully account for differing detectability when comparing WVC studies.

New records of bat flies (Diptera, Streblidae and Nycteribiidae) in Cerrado of Central Brazil

Here we record the occurrence of 38 species, including 30 species of Streblidae and eight species of Nycteribiidae. Of these, 12 are new records for the Distrito Federal, three are new for the Cerrado, and one, Trichobius johnsonae Wenzel, 1966 is the first record from Brazil. We also recorded a yet undescribed species of Basilia from the district.

Effect of light intensity on food detection in captive great fruit-eating bats, Artibeus lituratus (Chiroptera: Phyllostomidae)

Bats are known for their well-developed echolocation. However, several experiments focused on the bat visual system have shown evidence of the importance of visual cues under specific luminosity for different aspects of bat biology, including foraging behavior. This study examined the foraging abilities of five female great fruit-eating bats, Artibeus lituratus, under different light intensities. Animals were given a series of tasks to test for discrimination between a food target against an inedible background, under light levels similar to the twilight illumination (18lx), the full moon (2lx) and complete darkness (0lx). We found that the bats required a longer time frame to detect targets under a light intensity similar to twilight, possibly due to inhibitory effects present under a more intense light level. Additionally, bats were more efficient at detecting and capturing targets under light conditions similar to the luminosity of a full moon, suggesting that visual cues were important for target discrimination. These results demonstrate that light intensity affects foraging behavior and enables the use of visual cues for food detection in frugivorous bats. This article is part of a Special Issue entitled: Neotropical Behaviour.

Prevalence and intensity of Streblidae in bats from a Neotropical savanna region in Brazil

Bats of the family Phyllostomidae are common hosts to streblids known as bat flies. Here, we discuss the component community, prevalence and intensity of infection with species of Streblidae on an assemblage of phyllostomid bats in the Cafuringa Environmental Protection Area (APA Cafuringa) in the core area of the Cerrado in Central Brazil. A total of 1 841 streblid individuals of 24 species occurred on 752 bats of 14 species. Ten species of streblids infected Glossophaga soricina (Pallas), whereas seven or fewer streblid species infected the other bat species. Nine bat fly species presented a prevalence of more than 50%, whereas some differences in the abundance of bat flies among hosts were observed. Strebla wiedemanni Kolenati, 1856 and Trichobius furmani Wenzel, 1966 were more host-specific compared to the other streblids, and they occurred in greater abundance on their preferred hosts. Trichobius uniformis Curran, 1935 and Strebla mirabilis (Waterhouse, 1879) were the least host-specific, occurring on five and six hosts, respectively.

Falco sparverius (Aves: Falconiformes) preying upon Nyctinomops laticaudatus (Chiroptera: Molossidae)

In Brazil, there are two published references on the diet of American kestrel falcons, Falco sparverius Linnaeus, 1758, and one is for the Cerrado biome. The only mammal prey so far found in the diet of F. sparverius was the rodent Calomys tener (Winge, 1887). Herein we report on daily hunting activities by American kestrel falcons at a factory in the city of Uberlândia, state of Minas Gerais, southeastern Brazil, during an attempt to remove a bat colony. Two American kestrel falcons were observed on 14 occasions during two consecutive days: in two of these occasions, they were hunting in pairs, from 12:00 p.m. to 3:00 p.m. on 06/X/2003, and from 07:00 a.m. to 11:00 a.m. on 07/X/2003. During this period, American kestrel falcons made 27 hunting attempts and captured four bats of the same species, Nyctinomops laticaudatus (E. Geoffroy St.-Hilaire, 1805) (14.81% success). This report corroborates observations made in the Northern hemisphere, where bats are a dietary item of this falcon. Our findings are noteworthy because they reveal that the known natural predators of bats are few not only in Brazil but also worldwide.