Cardioderma Research Articles

Roost selection by synanthropic bats in rural Kenya: implications for human-wildlife conflict and zoonotic pathogen spillover.

Many wildlife species are synanthropic and use structures built by humans, creating a high-risk interface for human-wildlife conflict and zoonotic pathogen spillover. However, studies that investigate features of urbanizing areas that attract or repel wildlife are currently lacking. We surveyed 85 buildings used by bats and 172 neighbouring buildings unused by bats (controls) in southeastern Kenya during 2021 and 2022 and evaluated the role of microclimate and structural attributes in building selection. We identified eight bat species using buildings, with over 25% of building roosts used concurrently by multiple species. Bats selected taller cement-walled buildings with higher water vapour pressure and lower presence of permanent human occupants. However, roost selection criteria differed across the most common bat species: molossids selected structures like those identified by our main dataset whereas Cardioderma cor selected buildings with lower presence of permanent human occupants. Our results show that roost selection of synanthropic bat species is based on specific buildings attributes. Further, selection criteria that facilitate bat use of buildings are not homogeneous across species. These results provide information on the general mechanisms of bat-human contact in rural settings, as well as specific information on roost selection for synanthropic bats in urbanizing Africa.

Natural Infection of Sandfly Vector and Reservoir Hosts Species with Leishmania Parasites in Mt. Elgon Cave Habitats in Kenya

Leishmaniasis is a major public health problem caused by a parasite of the genus Leishmania which is transmitted through the bite of an infected female phlebotomine sandfly. However, the disease epidemiology on interactions of causative agents, reservoir hosts, and vectors in areas where there is a high prevalence of the disease needs to be properly understood to inform effective control. The present study was conducted to determine natural infection by Leishmania parasites in phlebotomine sandfly vectors and suspected reservoir hosts found in caves in Mount Elgon in Kenya. Sandflies, bats and rock hyraxes were found inhabiting the assessed caves in the study area. A total of 5688 sandflies collected from caves were morphologically identified and analyzed for infectivity with Leishmania parasites by molecular characterization sequencing using Cytochrome c oxidase subunit 1 (COI). Giemsa-stained blood smears and spleen and liver impression smears prepared from bats, and hyraxes collected from the same caves were examined microscopically for Leishmania amastigotes. The sandflies, bats, and hyraxes were identified morphologically using taxonomic keys. The results showed that randomly selected COI sequences (n = 5) of three different morphologically identified Phlebotomus species were positive for Leishmania based on their molecular characteristics. Five species of bats were identified, and they were significantly more abundant compared to hyraxes (χ2 = 16.7845, df = 7, P = 0.0002). The bats’ species had a higher prevalence of Leishmania parasites compared to hyraxes (F = 7.342, P = 0.0043). Cardioderma cor, Chaerephon pumilus and Rhinolophus clivosus bat species had more than 5% Leishmania parasite prevalence rate. Leishmania amastigote density was significantly higher in the liver (F = 39.232, P < 0.001) compared to the density in the blood (F = 75.1124, P < 0.001) of bats and hyraxes. This study has shown that transmission of Leishmania parasites in Mt. Elgon caves involves vertebrate reservoir hosts (bats and hyraxes) and the insect vector species (sandfly). Therefore, disruption of the life cycle of the Leishmania parasites should be done by targeting these reservoir animals and the sandfly vector.

A new genus and species of bat chiggers (Acariformes: Trombiculidae) from Kenya

A new genus and species of chigger mites, Minteracarus mombasa n. gen., n. sp., has been described from the heart-nosed bat, Cardioderma cor (Peters) (Chiroptera: Megadermatidae) in Mombasa, Kenya. The description was based on the material identified as a new species of the genus Trombicula Berlese, 1905 by P.H. Vercammen-Grandjean, but remained undescribed until the present.

Singing strategies are linked to perch use on foraging territories in heart-nosed bats.

Acoustic communication allows animals to coordinate and optimize resource utilization in space. Cardioderma cor, the heart‐nosed bat, is one of the few species of bats known to sing during nighttime foraging. Previous research found that heart‐nosed bats react aggressively to song playback, supporting the territorial defense hypothesis of singing in this species. We further investigated the territorial defense hypothesis from an ecological standpoint, which predicts that singing should be associated with exclusive areas containing a resource, by tracking 14 individuals nightly during the dry seasons in Tanzania. We quantified the singing behavior of individuals at all perches used throughout the night. Using home range analysis tools, we quantified overall use, night ranges and singing ranges, as well as areas used in early and later time periods at night. Males sang back and forth from small (x¯ = 3.48 ± 2.71 ha), largely exclusive areas that overlapped with overall night ranges used for gleaning prey. Individuals varied in singing effort; however, all sang significantly more as night progressed. Subsequently, areas used earlier at night and overall use areas were both larger than singing areas. Individuals varied in singing strategies. Some males sang for long periods in particular trees and had smaller core areas, while others moved frequently among singing trees. The most prolific singers used more perches overall. Our results support the hypothesis that acoustic communication repertoires evolved in support of stable foraging territory advertisement and defense in some bats.

We eat meat: a review of carnivory in bats

Abstract Some bat species in the families Phyllostomidae, Megadermatidae, and Nycteridae have long been known to consume terrestrial vertebrates and, more recently, reports of aerial‐hawking vespertilionid carnivores have surfaced. We review the diets, hunting behaviour and roosting ecology of 17 bat species that are known to consume terrestrial vertebrates: Vampyrum spectrum, Chrotopterus auritus, Trachops cirrhosus, Macroderma gigas, Megaderma (Lyroderma) lyra, Nycteris grandis, Nyctalus lasiopterus, Nyctalus aviator, Ia io, Antrozous pallidus, Cardioderma cor, Phyllostomus hastatus, Mimon (Gardnerycteris) crenulatum, Mimon cozumelae, Tonatia saurophila, Tonatia bidens, and Lophostoma silvicolum. Data on their diet and roosts were obtained from 241 original works, with considerable differences in the amount of research and information available among species. Carnivorous bats were found to belong to an ecologically diverse group and share little but their diet. Therefore, we define a carnivorous bat as a bat that, either year‐round or seasonally, uses terrestrial vertebrates as the main component of its diet, at least in part of its geographic range. We conclude from available data that Mimon crenulatum, Lophostoma silvicolum, Mimon cozumelae, Phyllostomus hastatus, Tonatia bidens, Tonatia saurophila, Cardioderma cor, and Antrozous pallidus use vertebrates as a minor part of their diet and should not be considered carnivorous. The nine other species we reviewed do fit into the definition of carnivorous bats, and can be further subdivided based on their ecology and the seasonality of their habits into three categories: year‐round predominantly gleaning carnivores (Chrotopterus auritus, Trachops cirrhosus, and Vampyrum spectrum), seasonal predominantly gleaning carnivores (Megaderma lyra, Macroderma gigas, and Nycteris grandis) and seasonal aerial‐hawking bird‐eating carnivores (Ia io, Nyctalus aviator, and Nyctalus lasiopterus).

Behavioral response to conspecific songs on foraging territories of the heart-nosed bat

Singing to create and defend territory boundaries is common among birds but rare in mammals. The African heart-nosed bat, Cardioderma cor, is hypothesized to use loud, low-frequency songs to reestablish foraging territories nightly. Territoriality can be defined ecologically, whereby an individual exclusively uses an area repeatedly, and behaviorally, through defense of an area. C. cor males sing on tightly abutting, exclusive areas nightly, which they return to throughout the season and sometimes across seasons. C. cor meets the ecological determinants of territoriality, but assessments of the use of song to maintain territories are lacking. We explore the singing behavior in this species by conducting song playback experiments within the borders of singing areas of 10 target individuals, with echolocation playbacks conducted as a control. In addition, we further explore the influence of song metrics on the behavioral response. Song playbacks prompted investigative and aggressive behavior, including passing by, approaching, and in one case, attacking the speaker, whereas echolocation did not. Additional post hoc analyses suggested that major song parameters, including song length, syllable frequency, intersyllable interval, and the number of double syllables comprising song stimuli influenced the level of response. For five bats we assessed whether their songs changed in response to the playback, and found that they sang faster, lower-frequency songs. These results are consistent with observations in other territorial animals including birds and gibbons, and provide a basis for further exploration of the territory defense hypothesis in the heart-nosed bat. We conclude that C. cor song features likely play an important role in mediating behavioral interactions within signaling networks of foraging bats. It has been hypothesized that birdsong first evolved in support of territorial defense because it offered a cost-effective alternative to patrolling large spaces by flight. Singing-like behaviors have also been documented in several species of bats but never as a tool for maintaining foraging territories. However, evidence of foraging territoriality is scarce for bats, likely due to technical challenges associated with documenting such behaviors for a small, flying animal that may travel large distances at night. Here, we show for the first time that a bat responds to conspecific songs in a manner strikingly similar to many songbirds, providing support from outside songbirds for the hypothesis that territorial defense is a key selective pressure for singing in small, flying animals. This work provides the important basis for continuing to explore the role of singing, including song variability, in natural bat behavior outside of the roost.

Bat species diversity and distribution in a disturbed regime at the Lake Bogoria National Reserve, Kenya

AbstractHuman population growth drives intrusion and progressive conversion of natural habitats for agriculture. We evaluated human impacts on bat species diversity and distribution among four vegetation types in and around Lake Bogoria National Reserve between November 2012 and July 2013. Plants were surveyed using the Braun–Blanquet cover/abundance method, whereas bats were sampled using standard mist nets erected on poles at ground level. Floristic similarity analysis revealed three broad vegetation assemblages, namely riverine vegetation, farmland and Acacia woodland/Acacia–Commiphora woodland. Two hundred and 33 bats representing eleven species in eleven genera and seven families were recorded. These were Epomophorus minimus, Rhinolophus landeri, Hipposideros caffer, Cardioderma cor, Lavia frons, Nycteris hispida, Chaerephon pumilus, Mops condylurus, Neoromicia capensis, Scotoecus hirundo and Scotophilus dinganii. Species richness estimators indicated that sampling for bats at ground level was exhaustive. Bat species richness and diversity were highest in the more structurally complex Acacia woodland compared to more homogenous farmlands where we recorded only common and generalist species that often occur in open habitats. The higher bat species richness and diversity in the Acacia woodland as compared to farmland underscore the importance of remnant natural savannah woodlands in the conservation of bats and other elements of biodiversity.

Intra- and Interspecific Variability of Echolocation Pulse Acoustics in the African Megadermatid Bats

The yellow-winged bat, Lavia frons, and the heart-nosed bat, Cardioderma cor, are sympatric species of the family Megadermatidae resident to East Africa. Cardioderma cor roost in groups and disperse to individual foraging areas at night, whereas L. frons roost in male-female pairs in Acacia trees within a foraging territory. Nightly foraging areas overlap across species, and thus interspecific differences in echolocation may reflect niche differences crucial for coexistence. Here we compare differences in echolocation from hand-released C. cor and L. frons, and L. frons individuals recorded during fly-bys. Furthermore, megadermatids display a host of social behaviors, including territoriality and singing, and thus intraspecific differences in echolocation may be important for facilitating behavior in this family but has not yet been assessed. We report the patterns of variability of echolocation by sex, body size, and individual of C. cor. We measured 354 pulses from 17 C. cor individuals and 35 pulses from four L. frons individuals in Tanzania. Up to four harmonics were observed in both C. cor and L. frons, with the second and third harmonics emphasized and the first suppressed. Cardioderma cor is a surface gleaner while L. frons is an aerial-hawker, and clear differences in frequency metrics (Fmin, Fmax, Fpeak) and duration reflect this. We measured 17 variables including temporal, frequency, and shape metrics for intraspecific C. cor pulse analyses. A MANOVA testing individuality on five principle components was significant, but performed poorly in a discriminant analysis. Body mass and forearm length did not correlate with any pulse metrics. Males had significantly lower Fmin and frequency contour parameters than females, although males were slightly smaller than females. These results suggest that L. frons and C. cor have clear interspecific differences in pulse acoustics that align with guild differences, and may serve heterospecific discrimination, while some intraspecific difference in C. cor, particularly by sex, are suggestive of other factors beyond navigation that influence pulse variability.

Singing away from home: Song is used to create and defend foraging territories in the African megadermatid bat, Cardioderma cor

The diversity of song repertoires and functions of singing in mammals are not well known. In bats, singing in the roost to court and defend mates has been studied; however, the concept of territorial behaviors and the role of singing outside of the roost is poorly understood. The heart-nosed bat, Cardioderma cor, roosts in mixed-sex and age groups in the hollows of baobab trees, but disperses to exclusive areas whereupon they move about foraging and singing. We investigated singing in this species by mist-netting, pit-tagging, and tracking 12 singing individuals during which we recorded songs and collected singing and movement behavioral data. We conducted song playbacks to further test song function. Male C. cor individuals return to same foraging area nightly, which are often over 100 m across, and favor perches where they sing back and forth with neighbors. Low-frequency, repetitive syllables are likely adapted for song transmission across the cluttered bush habitat. Songs vary within and across individuals both spectrally and temporally. Song playbacks elicited aggressive responses, confirming that these bats use song as part of their territorial defense strategy, similar to the way song is used by many songbirds.

Natural infection of bats with Leishmania in Ethiopia

The leishmaniases, a group of diseases with a worldwide-distribution, are caused by different species of Leishmania parasites. Both cutaneous and visceral leishmaniasis remain important public health problems in Ethiopia. Epidemiological cycles of these protozoans involve various sand fly (Diptera: Psychodidae) vectors and mammalian hosts, including humans. In recent years, Leishmania infections in bats have been reported in the New World countries endemic to leishmaniasis. The aim of this study was to survey natural Leishmania infection in bats collected from various regions of Ethiopia. Total DNA was isolated from spleens of 163 bats belonging to 23 species and 18 genera. Leishmania infection was detected by real-time (RT) PCR targeting a kinetoplast (k) DNA and internal transcribed spacer one (ITS1) gene of the parasite. Detection was confirmed by sequencing of the PCR products. Leishmania kDNA was detected in eight (4.9%) bats; four of them had been captured in the Aba-Roba and Awash-Methara regions that are endemic for leishmaniasis, while the other four specimens originated from non-endemic localities of Metu, Bedele and Masha. Leishmania isolates from two bats were confirmed by ITS1 PCR to be Leishmania tropica and Leishmania major, isolated from two individual bats, Cardioderma cor and Nycteris hispida, respectively. These results represent the first confirmed observation of natural infection of bats with the Old World Leishmania. Hence, bats should be considered putative hosts of Leishmania spp. affecting humans with a significant role in the transmission

A new species of Grandjeana (Acari: Trombiculidae) from heart-nosed bat (Chiroptera: Megadermatidae) in Ethiopia (Africa) with notes to biogeography of this genus

AbstractA new chigger mite Grandjeana kanuchi sp. n. collected from the bat Cardioderma cor (Peters, 1872) (Megadermatidae) in Ethiopia (North-East Africa) is described. Additional comments on hosts and distribution records of the chiggers of genus Grandjeana are provided. With the newly described species the genus Grandjeana includes 10 species, three of them are occurring in Africa and seven in South Asia. Present findings suggest that this genus has the geographic distribution in Ethiopian and Oriental regions with a strong association with selected families of Chiroptera.

New discoveries on the ecology and echolocation of the heart-nosed bat Cardioderma cor with a contribution to the phylogeny of Megadermatidae

In this study we report findings in roosting ecology, ectoparasites, echolocation characteristics and the phylogenetic position of Cardioderma cor, an impressive bat species that is distributed throughout the savannas and woodlands of eastern Africa. For individuals caught in Mago National Park, Ethiopia, we recorded broadband frequency-modulated ultrasound signals having very short duration (2 ms) with three harmonic components. The mean peak frequency of the first harmonic was 50.4 kHz and the mean inter-signal interval was 186 ms. Phylogenetic reconstructions of all known species from the family Megadermatidae based on DNA sequences of two mitochondrial and four nuclear genes yielded incongruent topologies (both Bayesian inference and maximum likelihood analysis) with only weak support for nodes. The phylogeny that combined all six loci into a species tree was not congruent with any previous inference based on dental or cranial characteristics, but it suggested separate generic status of two Megaderma species. However, additional genetic data are necessary to resolve the phylogeny of Megadermatidae, a group that probably evolved by simultaneous divergence of all five extant lineages.

Nuclear organization of cholinergic, putative catecholaminergic and serotonergic systems in the brains of five microchiropteran species

The current study describes, using immunohistochemical methods, the nuclear organization of the cholinergic, catecholaminergic and serotonergic systems within the brains of five microchiropteran species. For the vast majority of nuclei observed, direct homologies are evident in other mammalian species; however, there were several distinctions in the presence or absence of specific nuclei that provide important clues regarding the use of the brain in the analysis of chiropteran phylogenetic affinities. Within the five species studied, three specific differences (presence of a parabigeminal nucleus, dorsal caudal nucleus of the ventral tegmental area and the absence of the substantia nigra ventral) found in two species from two different families ( Cardioderma cor; Megadermatidae, and Coleura afra; Emballonuridae), illustrates the diversity of microchiropteran phylogeny and the usefulness of brain characters in phylogenetic reconstruction. A number of distinct differences separate the microchiropterans from the megachiropterans, supporting the diphyletic hypothesis of chiropteran phylogenetic origins. These differences phylogenetically align the microchiropterans with the heterogenous grouping of insectivores, in contrast to the alignment of megachiropterans with primates. The consistency of the changes and stasis of neural characters with mammalian phylogeny indicate that the investigation of the microchiropterans as a sister group to one of the five orders of insectivores to be a potentially fruitful area of future research.

Bat species diversity and distribution in three vegetation communities of Meru National Park, Kenya

AbstractDiversity and distribution of bats was determined in four vegetation types in and around Meru National Park, Kenya between September 2000 and February 2001. Bat‐habitat studies were based on plant species dominance, cover and farming activities. Bats were captured using standard mist nets (18 m long × 2 m high) erected on poles averaging 3 m. Vegetation was broadly grouped as Acacia or Combretum wooded grassland, or Acacia–Commiphora bushland and studied using the Braun‐Blanquet method. Analysis of floristic similarity showed five vegetation species assemblages in the three broad categories. Four hundred and ninety‐five bats representing eleven genera in seven families were recorded. These were Epomophorus labiatus, E. wahlbergi, Cardioderma cor, Lavia frons, Myotis welwitschii, Scotoecus hirundo, S. leucogaster, Pipistrellus kuhlii, Mops condylurus, Chaerephon bemmeleni, Mormopterus sp., Hipposideros caffer, H. commersoni, Nycteris arge and Rhinolophus landeri. This was the first record of N. arge, M. welwitschii, C. bemmeleni and a Mormopterus species in eastern Kenya. The Combretum community was most equitable (E = 0.51) with nine bat species records, while farming areas had only four. The low species richness and increased dominance of a few generalist species on farms may be indicative of different levels of disturbance.

The role of prey-generated sounds, vision, and echolocation in prey localization by the African batCardioderma cor (Megadermatidae)

Cardioderma cor responded with head movements and flight toward speakers broadcasting calls of frogs and crickets which contained only sonic frequencies. Unlike the frog-eating bat,Trachops cirrhosus, they did not make contact with the speakers. Prey movements that generated sonic and ultrasonic sounds were both sufficient and necessary for the bats to localize and capture prey. Prey dragged across a glass sheet with a thin layer of water did not generate sounds and bats did not attempt to capture these prey, even with the availability of visual and echolocation cues. There was no evidence for the use of visual cues while hunting; bats did not localize prey more readily in light than darkness. Prey were presented such that their movements initially generated sounds, but then the prey moved onto the water layer of the glass sheet and sounds were eliminated. The bats emitted echolocation signals while hunting in this situation; however, the information from these signals was not utilized. The bats landed at the site that prey last made sound. These results demonstrate the importance of passive hearing for prey localization in this bat, and further suggest that when preygenerated sounds and echolocation signals offer conflicting information the bat's behavior is guided by the former.

Nocturnal Behavior of the African False Vampire Bat (Cardioderma cor)

Nocturnal behavior of the African false vampire bat ( Cardioderma cor ) was studied in bushland in southern Kenya, East Africa. Observations were made with a night-viewing device, and work was concentrated on the foraging strategy. This bat roosts in hollow baobab trees in groups of up to some 80 individuals. At night each bat occupies an exclusive foraging area. Individuals spend considerable time singing and establishing their exclusive areas during the March–April wet season when food is abundant; these areas have greatest survival value toward the end of the long May–October dry season, when food is in short supply, foraging occupies nearly the entire night, and singing is infrequent. Nocturnal time budget is characterized by long periods spent perching in low vegetation and listening for terrestrial prey. Flights to capture prey and between perches are brief and short, usually lasting less than 5 seconds and covering less than 25 meters. Food is typically captured on the ground, and consists primarily of large, ground-dwelling beetles, but centipedes and scorpions, and on rare occasions small bats, are also taken. During parts of the rainy seasons leaf gleaning and aerial captures of insects are important; at these times katydids (Tettigoniidae), locusts (Locustidae), and sphinx moths (Sphingidae) are major food items. Pronounced seasonal shifts in foraging behavior associated with the bimodal pattern of rainfall are discussed, and the evolution of the bat's unusual style of foraging is considered.