African Bats Research Articles

Indirect Flight of an African Bat to Israel: An Example of the Potential for Zoonotic Pathogens to Move between Continents

The transmission of harmful pathogens during commercial air flights is an increasing health concern. A potential, yet relatively overlooked source of zoonotic infectious diseases involves collisions of birds and bats with aircraft and long distance transport of their carcasses. We report a case of aerial transportation of the remains of an African fruit bat over three continents, following a collision with an aircraft, and demonstrate the relative ease with which zoonotic pathogens, such as rabies virus or other viruses associated with bats, may cross national boundaries and continents even. Improper handling and disposal of animal remains by airport personnel, may lead to exposure of both humans and local fauna to exotic pathogens. This in turn may trigger an epidemic with potentially devastating results.

Amniogenesis in the African yellow bat, Scotophilus dinganii

The African yellow house bat, Scotophilus dinganii, was found to be seasonally monestrus, carrying a single foetus in each of the two uterine horns of the bicornuate uterus. Implantation was superficial, with amniogenesis initiated early during embryogenesis. The amnion in S. dinganii was a schizamnion, and it is deduced that its formation was preceded by cavitation of the inner cell mass, with formation of the definitive amniotic cavity, where the floor of the cavity eventually formed the embryonic disc and its roof the ectodermal part of the true or definitive amnion.

Amniogenesis in the African yellow bat, Scotophilus dinganii

The African yellow house bat, Scotophilus dinganii, was found to be seasonally monestrus, carrying a single foetus in each of the two uterine horns of the bicornuate uterus. Implantation was superficial, with amniogenesis initiated early during embryogenesis. The amnion in S. dinganii was a schizamnion, and it is deduced that its formation was preceded by cavitation of the inner cell mass, with formation of the definitive amniotic cavity, where the floor of the cavity eventually formed the embryonic disc and its roof the ectodermal part of the true or definitive amnion.

Hearing in large ( Eidolon helvum) and small ( Cynopterus brachyotis) non-echolocating fruit bats

Comparing the hearing abilities of echolocating and non-echolocating bats can provide insight into the effect of echolocation on more basic hearing abilities. Toward this end, we determined the audiograms of two species of non-echolocating bats, the straw-colored fruit bat ( Eidolon helvum), a large (230–350 g) African fruit bat, and the dog-faced fruit bat ( Cynopterus brachyotis), a small (30–45 g) bat native to India and Southeast Asia. A conditioned suppression/avoidance procedure with a fruit juice reward was used for testing. At 60 dB SPL, the hearing range of E. helvum extends from 1.38 to 41 kHz with best sensitivity at 8 kHz; the hearing range of C. brachyotis extends from 2.63 to 70 kHz with best sensitivity at 10 kHz. As with all other bats tested so far, neither species was able to hear below 500 Hz, suggesting that they may not use a time code for perceiving pitch. Comparison of the high-frequency hearing abilities of echolocating and non-echolocating bats suggests that the use of laryngeal echolocation has resulted in additional selective pressure to hear high frequencies. However, the typical high-frequency sensitivity of small non-echolocating mammals would have been sufficient to support initial echolocation in the early evolution of bats, a finding that supports the possibility of multiple origins of echolocation.

Aspects of reproduction in the seasonally breeding African yellow bat, Scotophilus dinganii (A. Smith, 1833)

Monthly collections of the African yellow bat, Scotophilus dinganii, were made in the Kruger National Park. Examination of serially sectioned reproductive tracts of females showed that the African yellow bat is a monoestrous species and that insemination, ovulation and fertilization took place during mid to late autumn (April to May). Early embryonic development of normally two embryos (one in each uterine horn) was retarded and implantation delayed until mid-winter (July), when the blastocysts implanted.

Trauma, disease and collateral damage: conflict in cimicids

The bed bugs and bat bugs (Hemiptera: Cimicidae) are unusual in being a gonochorist (separate male and female genders) taxon with obligate traumatic insemination. Males of all the species in this family have a lanceolate paramere (intromittent organ) which they use to pierce the female's body wall and inseminate directly into her haemocoel, despite the presence of a functional female genital tract. Mating is tightly linked to the feeding cycle in Cimex lectularius, the common bed bug. In this paper, I examine key aspects of the reproductive anatomy and behaviour of C. lectularius that underpin the nature of the conflict over mating rate in this species. I then examine the consequences of traumatic insemination for female fitness and examine potential mechanisms that might underpin those costs. Finally, the collateral consequences of the male reproductive tactic on other males of C. lectularius and the African bat bug, Afrocimex constrictus are examined.

Aspects of reproduction in the seasonally breeding African yellow bat, Scotophilus dinganii (A. Smith, 1833)

Monthly collections of the African yellow bat, Scotophilus dinganii, were made in the Kruger National Park. Examination of serially sectioned reproductive tracts of females showed that the African yellow bat is a monoestrous species and that insemination, ovulation and fertilization took place during mid to late autumn (April to May). Early embryonic development of normally two embryos (one in each uterine horn) was retarded and implantation delayed until mid-winter (July), when the blastocysts implanted.

Estimation of population density of Eidolon helvum on the island of Príncipe, Gulf of Guinea / Estimation de densité de population de Eidolon helvum sur l'île de Príncipe, Golfe de Guinée

AbstractEidolon helvum is a widespread African fruit bat. It is migratory and can form colonies of millions of individuals. On Príncipe, in the Gulf of Guinea, there are seemingly large numbers of E. helvum . Here, they have lost their migratory behaviour and rely on the availability of the year-round food resources on the island, which is small (128 km

Estimation of population density of Eidolon helvum on the island of Príncipe, Gulf of Guinea / Estimation de densité de population de Eidolon helvum sur l'île de Príncipe, Golfe de Guinée

AbstractEidolon helvum is a widespread African fruit bat. It is migratory and can form colonies of millions of individuals. On Príncipe, in the Gulf of Guinea, there are seemingly large numbers of E. helvum . Here, they have lost their migratory behaviour and rely on the availability of the year-round food resources on the island, which is small (128 km

Isolation of Lagos Bat Virus from Water Mongoose

A genotype 2 lyssavirus, Lagos bat virus (LBV), was isolated from a terrestrial wildlife species (water mongoose) in August 2004 in the Durban area of the KwaZulu-Natal Province of South Africa. The virus isolate was confirmed as LBV by antigenic and genetic characterization, and the mongoose was identified as Atilax paludinosus by mitochondrial cytochrome b sequence analysis. Phylogenetic analysis demonstrated sequence homology with previous LBV isolates from South African bats. Studies performed in mice indicated that the peripheral pathogenicity of LBV had been underestimated in previous studies. Surveillance strategies for LBV in Africa must be improved to better understand the epidemiology of this virus and to make informed decisions on future vaccine strategies because evidence is insufficent that current rabies vaccines provide protection against LBV.

Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia: Megachiroptera) from the islands of the Gulf of Guinea. II. Integration and levels of multivariate fluctuating asymmetry across a geographical range

Abstract Using a set of cranial morphometric characters, trends of variation in multivariate fluctuating asymmetry were evaluated and compared in populations of African fruit bats Rousettus egyptiacus and Eidolon helvum from the Gulf of Guinea islands, and the adjacent mainland. Levels of asymmetry were compared across populations and species, and significant differences were found in both comparisons. Differences coincided with species-specific patterns of morphological and genetic differentiation. Concordance of correlation matrices of asymmetry was also compared. Results were significant; concordance is hypothesized to be a by-product of developmental processes that produce the ‘fox-like’ morphology shared by these species. Consistency of asymmetry patterns suggests that the developmental pathway producing it is highly canalized. A prediction of the above hypothesis is that a radical change in the ‘fox-like’ structural pattern would result in breakage of the asymmetry parameter associated with it.

Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia: Megachiroptera) from the islands of the Gulf of Guinea. I. Variance and size components of bilateral variation

Abstract A set of cranial characters was examined in the fruit bats Rousettus egyptiacus and Eidolon helvum to compare trends and relative importance of major components of bilateral morphometric variation, and their relationship with character size. Using two-way, sides-by-individuals ANOVA, four components of variation were estimated for each bilateral variable: individual variation (I), directional asymmetry (DA), non-directional asymmetry (NDA) and measurement error (E). Both species exhibit similar major trends of variation in asymmetry across characters, as shown by principal component analysis, using variance components as variables. Degree of interspecific congruence among characters was confirmed by a two-way ANOVA with species and variance components as fixed factors. Congruence of asymmetry patterns between species suggests that the concept of population asymmetry parameter (PAP) could be extended to higher hierarchies. PAPs above the species level may result from common mechanisms or similar developmental constraints acting on species’ buffering capacities and morphological integration processes.

Sex discrimination and roostmate recognition by olfactory cues in the African bats, Mops condylurus and Chaerephon pumilus (Chiroptera: Molossidae)

AbstractThe ability of two species of African insectivorous bats (Angola free‐tailed Mops condylurus and little free‐tailed Chaerephon pumilus) to distinguish between males and females and roostmates from strangers in scent‐choice experiments was tested. Both sexes of M. condylurus and male C. pumilus discriminated between sexes based on odours collected from the interaural and muzzle glandular areas, whereas female C. pumilus did not show any preference in either trials. Female M. condylurus from intermediate sized colonies (c. 200–600 individuals) distinguished female roostmates from strangers. There is some indication that roostmate recognition may vary inversely with the colony size of the test‐subject suggesting that recognition is individually based, but further studies are necessary to determine if this is so. Histological work revealed that the interaural and muzzle area contain sebaceous glands and that the quantity of the glandular tissue is sexually dimorphic in both species for the interaural area, with males having more tissue, but not for the muzzle area. The presence of osmetrichia using SEM was also observed in the interaural area of both sexes of M. condylurus and in male C. pumilus. Their presence and association with sebaceous glands, as well as the results of the scent‐choice experiments are indirect evidences of use of chemical signals, possibly pheromones, by these bats.

Evidence for organism-wide asymmetry in five bird species of a fragmented afrotropical forest

Empirical evidence for between-trait correlation in fluctuating asymmetry (FA) at the individual level is generally lacking or contradictory. Yet the assumption of organism-wide asymmetry, estimated by the asymmetry of any given trait, is inherent to most studies that use FA as a measure of developmental stability (DS). A commonly assumed reason for this weak between-trait correlation is the low repeatability of individual, single-trait asymmetry. In this paper we describe high repeatability and significant between-trait correlation in population- and individual-level FA in five afrotropical bird species inhabiting a fragmented cloud forest. Absence of anti-symmetry and of between-trait correlation in signed FA levels permits us to translate the observed patterns into the presumed underlying DS, using the concept of hypothetical repeatability. This correction, which has not been applied before in this context, proved adequate as it yielded correlations comparable to those found at the population level.

The role of amateurs in the growth of bat conservation and research in South Africa

During the 1980s and 1990s, Britain experienced an unprecedented increase in scientific and public interest in bat conservation, culminating in 90 ‘bat groups’ by 1992. In South Africa, bats are poorly protected or unprotected, and most of the country's 54 species are poorly known. With the formation of bat interest groups in Kwa- Zulu-Natal and Gauteng in 1994 and 1995, the British ‘bat group’ conservation model was applied in a South African context. The primary aim of South African bat groups has been to promote bats, bat research and bat conservation through public participation and education, and the training of amateur ‘bat workers’ by scientists. I evaluate the success of this approach, based on activities of the Durban Bat Interest Group (DBIG) over four years (1994–1997 inclusive), and on estimates of media impact available for 1994–1996 inclusive. The number of public activities increased by between 14% and 44% per year. Some 12 million South Africans have been exposed to a positive message abou...

Echolocation calls of twenty southern African bat species

Echolocation data and sonograms are reported for twenty southern African bat species from 13 localities, recorded with the Pettersson D980 time-expansion bat detector. Data for eight species have not previously been reported. For seven species, two or more individuals were analysed in a range of situations, including handheld, tethered and free-flying (in a room and in different natural habitats). Sonograms, and seven echolocation call parameters agreed, with a few exceptions, with published data for individual species. Although intraspecific variation in echolocation call structure was documented, species tended to have recognisable ‘vocal signatures’, particularly when dominant frequency and harmonic structure were considered. The latter variables are readily retrieved by time expansion detectors, but not by frequency division or heterodyne detectors. Although generally they should be interpreted with caution, recordings from room-flown (five species) and hand-held (six species) bats obtained during thi...

On a collection of bats (Chiroptera) from Kikwit, Democratic Republic of the Congo

Summary. - The collection of vertebrates made in Kikwit in the aftermath of the 1995 Ebola haemorrhagic fever epidemic included 538 bat specimens, representing 18 species. This collection contains large numbers of a very common species, Chaerephon pumila, but also of Chaerephon ansorgei, which was not yet reported in such large numbers. Other rather common African bat species - e.g. Pipistrellus nanus - are represented with two specimens only. Surprisingly, some rare species were found to be present in the collection: e.g. Casinycteris argynnis, Miniopterus minor, Myopterus whitleyi, especially when the limited time over which the collection is made, is considered. For each of the species, measurements are presented - either in detail or in summary - and comparisons are made with the dimensions found in the literature. The distribution of the species in the Democratic Republic of the Congo is discussed based on literature data. For most species, information on reproductive data is given.

Female Reproduction in Two Species of Tropical Horseshoe Bats (Rhinolophidae) in Zimbabwe

Female reproduction was studied in sympatric populations of two species of African horseshoe bats in a seasonal tropical environment of central Zimbabwe. Both Rhinolophus simulator and its largest African congener, R. hildebrantii , were monotocous and monestrous, and reproduction was highly seasonal. In 3 consecutive years, R. simulator gave birth consistently later (15–20 days) than R. hildebrantii , and early embryonic development was retarded in the smaller R. simulator . Copulations occurred during June and July of the cooldry season, and both species gave birth to single offspring during separate synchronized periods of parturition at the start of the wet season. Lactation in both species coincided with the period of maximal rainfall, but the weaning period of R. hildebrantii was distinctly long.

Male sexual ornament size but not asymmetry reflects condition in stalk–eyed flies

Models of sexual selection predict that females use ornament size to evaluate male condition. It has also been suggested that ornament asymmetry provides females with accurate information about condition. To test these ideas we experimentally manipulated condition in the stalk-eyed fly, Cyrtodiopsis dalmanni, by varying the amount of food available to developing larvae. Males of this species have greatly exaggerated eyestalk length and females prefer to mate with males with wider eyespans. Our experiments show that male ornaments (eyestalks) display a disproportionate sensitivity to condition compared with the homologous character in females, and to non-sexual traits (wing dimensions). In contrast, in neither sex did asymmetry reflect condition either in sexual ornaments or in non-sexual traits. We conclude that ornament size is likely to play a far greater role in sexual selection as an indicator of individual condition than does asymmetry.

A case of snake predation upon bats in northern Morocco: some implications for designing bat grilles

During a study of North African mouse-eared bats in Morocco in August 1993 (Arlettaz et al., 1997) some accidental observations on chiropterophagy by the snake Coluber hippocrepis were made. This adds a new species to the list of bat-eating serpents documented so far (for a general review see Schätti, 1984). In addition, our observations lead to some recommendations for the construction of bat grilles at underground sites to minimize predation risk by snakes or other predators upon bats.