Insectivory in captive Livingstone's and Rodrigues fruit bats Pteropus livingstonii and P. rodricensis (Chiroptera: Pteropodidae): a behavioural adaptation for obtaining protein

Captive Pteropus livingstonii and P. rodricensis were observed actively to catch and eat insects. Both species adopt the same technique to trap flying insects, using their wings to envelop them. The spontaneity of the response indicates that it is not an artefact of captivity. The behaviour was observed in captive-bred P. rodricensis which had no prior access to insects, suggesting that it is also innate. A higher rate of successful captures was recorded for an older, wild caught P. livingstonii female, indicating that the effectiveness of the technique used may improve with age. Significant differences in the amount of time spent catching insects by males and females were evident in this species. This study supports suggestions that insects are eaten by some megachiopterans in order to supplement their protein intake.     

The effect of contraceptive implants on the behavior of female Rodrigues fruit bats,Pteropus rodricensis

This study investigated the effects of a melengestrol acetate contraceptive implant on the behavior of captive Rodrigues fruit bats (Pteropus rodricensis). Eighteen female bats (nine controls and nine implanted animals) were studied over three 4 week periods: prior to implantation, immediately postimplantation, and 6 months postimplantation. The only significant differences found 6 months postimplantation were that time spent hanging alert decreased in both groups and, concurrently, amount of time spent engaged in other activities, most noticeably social interactions, increased. In connection with this, the number of nearest neighbors increased. However, these changes were seen in all bats and were also associated with the increasing size of the resident colony. There were no significant differences between the two groups of bats in the number of nearest neighbors or sexual partners over the course of the study. The physical effects of the contraceptive implants, increased weight gain and retarded hair regrowth above the incision site, were very clearly shown. There was a 22% rate of rejection/loss of the implants. None of the implanted bats produced offspring postimplantation. This study has shown that melengestrol acetate implants are an effective way to limit reproduction in female Rodrigues fruit bats, at least in the short term, and have no effect on the behavior of this highly social species. © 1996 Wiley-Liss. Inc.     

亚洲南部球果蝠Sphaerias blanfordi(Thomas,1891)的亚种分化

球果蝠Sphaerias blanfordi(Thomas,1891)是亚洲南部喜马拉雅-印度支那地区的特有种,甚为罕见而少有报道.曾被认为是单型种,几乎无雄性特征的描述.蔡桂全和张遁治(1980)根据采自西藏东南部墨脱的2只雄性标本订了一亚种一墨脱亚种Sphaerias blanfordi motuoensis,其主要特征是颈下侧有一对灰黄色的圆形毛斑.中国科学院昆明动物研究所先后在云南西北部高黎贡山地区采获25号标本(9♂♂,16♀♀),发现球果蝠两性在外形上有明显的性别差异,雄性的颈下侧有一对圆形、灰黄色的刷状毛斑,但雌性均无;对比墨脱标本,认为墨脱亚种的鉴别特征不可靠,亚种不能成立.Lunde(2003)曾报道采自越南北部Mt.Tay Con Linh Ⅱ地区的43号标本,其前臂长和上犬齿外宽明显与印度、缅甸和云南西北部高黎贡山地区的标本不同,可能是真正的地理亚种.     

The Egyptian fruit bat Rousettus aegyptiacus (Chiroptera: Pteropodidae) in the Palaearctic: Geographical variation and taxonomic status

Two metrically defined subspecies have traditionally been recognised within the Palaearctic distribution range of the Egyptian fruit bat Rousettus aegyptiacus; the larger R. a. aegyptiacus in Egypt and the northern part of the Middle East and the smaller R. a. arabicus in the southern Middle East. An extensive material of R. aegyptiacus from all parts of this area, i.e. the Levant (incl. Turkey and Cyprus), Egypt (incl. Sinai), northern Sudan, Yemen, Oman, Iran, and Pakistan, as well as comparative samples from its sub-Saharan range, were tested using both morphological and genetic approaches in order to revise the species’ taxonomic status. The results indicated two possible processes, depending on the method used. Genetic analysis of the mitochondrial genome (nd1 and cytb) indicated low variation (< 2.0% of genetic distance) and lack of geographical structure while morphometric analysis indicated significant metric differences. Two basic size morphotypes were found within the Palaearctic range, with a rather mosaic-like geographical distribution and a lack of clear size distinction between the two categories, though intermediate types were detected. Thus, we suggest that all Palaearctic populations of R. aegyptiacus represent one form, the nominotypical subspecies, which is uniform in genetic traits but plastic in metric traits.     

Clinal variation in body size and sexual dimorphism in an Indian fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae)

Geographic variation in body size and sexual dimorphism of the short‐nosed fruit bat (Cynopterus sphinx) was investigated in peninsular India. Bats were sampled at 12 localities along a 1200 km latitudinal transect that paralleled the eastern flanks of the Western Ghats. The geographic pattern of variation in external morphology of C. sphinx conforms to the predictions of Bergmann's Rule, as indicated by a steep, monotonic cline of increasing body size from south to north. This study represents one of the first conclusively documented examples of Bergmann's Rule in a tropical mammal and confirms that latitudinal clines in body size are not exclusively restricted to temperate zone homeotherms. Body size was indexed by a multivariate axis derived from principal components analysis of linear measurements that summarize body and wing dimensions. Additionally, length of forearm was used as a univariate index of structural size to examine geographic variation in a more inclusive sample of bats across the latitudinal transect. Multivariate and univariate size metrics were strongly and positively correlated with body mass, and exhibited highly concordant patterns of clinal variation. Stepwise multiple regression on climatological variables revealed that increasing size of male and female C. sphinx was associated with decreasing minimum temperature, increasing relative humidity, and increasing seasonality. Although patterns of geographic size variation were highly concordant between the sexes, C. sphinx also exhibited a latitudinal cline in the magnitude and direction of sexual size dimorphism. The size differential reversed direction across the latitudinal gradient, as males averaged larger in the north, and females averaged larger in the south. The degree of female‐biased size dimorphism across the transect was negatively correlated with body size of both sexes. Canonical discriminant analysis revealed that male‐ and female‐biased size dimorphism were based on contrasting sets of external characters. Available data on geographic variation in the degree of polygyny in C. sphinx suggests that sexual selection on male size may play a role in determining the geographic pattern of sexual size dimorphism.     

Altered flower/fruit clusters of the kitul palm used as roosts by the short-nosed fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae)

The short-nosed fruit bat (Cynopterus sphinx) creates bell-shaped cavities in flower/fruit clusters of the kitul palm (Caryota urens) by chewing and severing flower and fruit strings. These cavities (stem tents) in which the bats roost are usually about one metre deep and 30 cm in diameter. We observed groups of bats roosting in fully-formed stem tents during the daytime, and the construction and subsequent occupancy of newly formed tent cavities. Stem tents are similar in principle to leaf tents except, instead of being formed when bats chew veins and the surrounding tissues of leaves, stem tents are formed in C. urens when bats completely cut several of the central flower/fruit strings. Flower/fruit strings are mostly severed when they are in an immature stage, at times when they are thin and widely spaced. Once these strings thicken and become heavily-laden with mature fruits, bats cannot penetrate the cluster to sever them. Our observations suggest that a single male enters an immature flower or fruit cluster either from below or the sides and severs the central strings along the peduncle. In early phases of stem-tent construction, C. sphinx severs flower/fruit strings at a rate of about one or two per day, and cluster alteration may continue upwards to two months. Only one immature flower/fruit cluster on a C. urens tree is available for alteration by bats at any given time. That this bat does not roost in the fruit/flower cluster during the day, when a tent is under construction, and the accumulation of chewed flower and fruit strings beneath such a cluster in the morning, suggests that tent construction by C. sphinx is a night-time activity.     

Baseline and stress-induced glucocorticoids during reproduction in the variable flying fox, Pteropus hypomelanus (Chiroptera: Pteropodidae)

Baseline and stress-responsive glucocorticoid (GC) levels were assessed during early pregnancy, late pregnancy, and lactation in female variable flying foxes (Pteropus hypomelanus) and in males over the same time period. Animals were maintained in a breeding colony in captivity. High levels of both cortisol and corticosterone were detected, with total plasma GC levels being among the highest documented in vertebrates (up to 3000 ng/ml in individual animals, with cortisol being the primary GC, accounting for approximately 78% of total GCs), and significantly greater in males than in females. Plasma levels of cortisol and corticosterone showed nearly identical profiles within each sex, with the exception of females in late pregnancy, in which corticosterone, but not cortisol, increased significantly. Baseline levels of plasma cortisol were highest in September (when pups were between 1 and 2 months of age) in both sexes, which may be related to the approaching onset of the mating period. There was a continuum in the magnitude of the response to stress (handling and sampling) over time in females, with the greatest stress response in early pregnancy, a dampened response during late pregnancy, and no significant stress response during lactation. Surprisingly, males failed to exhibit elevated GCs after this stress, but did have significant stress-induced hyperglycemia and suppression of plasma testosterone levels. This may be due to their high (perhaps maximal) baseline levels, which suggests that being in a breeding group was chronically stressful for males.     

Volatile compounds in shoulder gland secretions of male flying foxes, genus Pteropus (Pteropodidae, Chiroptera)

The shoulder gland secretions of captive males of the Indian flying fox (Pteropus giganteus), the little golden-mantled flying fox (P. pumilus), the island flying fox (P. hypomelanus), and the large flying fox (P. vampyrus) were examined by gas chromatography-mass spectrometry. Sixty-five compounds, including hydrocarbons, carboxylic acids, alcohols, aldehydes, ketones, esters, and amides, were identified among the four species. Many of these compounds, such as squalene, cholesterol, and C5-C16 straight- and branched-chain carboxylic acids, are typical of tetrapod epidermal products. Aldehydes, which were detected in all four Pteropus species, and some straight- and branched-chain ketones, which were detected in P. hypomelanus and P. pumilus, are known from other mammalian skin glands. Acetophenone, 4-acetoxyacetophenone, and 4-hydroxyacetophenone were observed in P. pumilus; the last compound comprised 37.1% of the total ion current. 2,3-Butanediol, a prominent component (5.2-19.3%) in the secretions of P. giganteus, P. hypomelanus, and P. pumilus, and C10 and C12 isopropyl esters and C10-C14 1-methylbutyl esters, observed in P. hypomelanus and P. vampyrus, have not previously been reported from vertebrates. alpha-Methyl-4-methoxybenzyl alcohol and dihydro-5-phenyl-2(3H)-furanone, from P. giganteus and P. pumilus, are new natural products. 1-Chloro-3-methyl-2-butene, another new natural product, and five C5 compounds exhibiting a similar isoprenoid structure were observed in P. giganteus. Striking contrasts were observed in the chemical profiles of the species we examined, with even general chemical classes differentially represented among them.     

Erythrocyte biochemistry of the grey-headed fruit bat (Pteropus poliocephalus)

1. Several haematological and biochemical parameters were measured in the erythrocytes of the grey-headed fruit bat. 2. The level of 2,3-diphosphoglycerate was almost twice that found in human erythrocytes. Similarly pyruvate kinase activity was more than twice that of man. 3. The activities of other enzymes of the glycolytic pathway were similar to those found in man. 4. The level of reduced glutathione (GSH) and the GSH regeneration rate in the erythrocytes of the bat were comparable to those found in man.     

Description of a new bat species of the tribe Scotonycterini (Chiroptera,Pteropodidae) from southwestern Cameroon

The tribe Scotonycterini is currently composed of three fruit bat species of the family Pteropodidae (Mammalia, Chiroptera) characterized by white fur patches on the head, specifically around the nose and behind the eyes: Scotonycteris zenkeri, S. ophiodon and Casinycteris argynnis. Herein a new species is described, Casinycteris campomaanensis sp. nov., based on female specimen collected in 2007 near the village Nkoélon-Mvini close to the Campo-Ma’an National Park, southwestern Cameroon. It is readily distinguished from the three other species of Scotonycterini by its body size and craniodental characteristics. Molecular analyses based on the complete mitochondrial cytochrome b gene indicate that the new species is the sister-group to C. argynnis and that the holotype of S. ophiodon is more closely related to Casinycteris than to S. zenkeri, rendering the genus Scotonycteris paraphyletic. Based on these results, morphological characters within the tribe Scotonycterini were reassessed and a new classification is proposed, in which the new species and S. ophiodon are placed in the genus Casinycteris.     

Phylogeny of African fruit bats (Chiroptera,Pteropodidae) based on complete mitochondrial genomes

Members of the family Pteropodidae, also known as Old World fruit bats, are represented in Africa by 14 genera and 44 species. Here, we sequenced 67 complete mitochondrial genomes from African and Asian pteropodids to better understand the evolutionary history of the subfamily Rousettinae, which includes most of the African species. An increased frequency of guanine to adenine transitions is detected in the mtDNA genomes of Macroglossus sobrinus and all species of Casinycteris and Scotonycteris. Our phylogenetic and molecular dating analyses based on 126 taxa and 15,448 characters indicate a low signal for deep relationships within the family, suggesting a rapid diversification during the Late Oligocene period of “warming.” Within the subfamily Rousettinae, most nodes are highly supported by our different analyses (all nucleotide sites, SuperTRI analyses of a sliding window, transversions only, coding genes only, and amino acid sequences). The results indicate the existence of four tribes: Rousettini—distributed from Africa through Mediterranean region and South Asia to South-East Asia; Eonycterini—found in Asia; and Epomophorini and Scotonycterini—restricted to sub-Saharan Africa. Although most interspecies relationships are highly supported, three parts of the Rousettinae mitochondrial tree are still unresolved, suggesting rapid diversification: (a) among the three subtribes Epomophorina (Epomophorus sensu lato, i.e., including Micropteropus, Epomops, Hypsignathus, Nanonycteris), Plerotina (Plerotes), and Myonycterina (Myonycteris, Megaloglossus) in the Late Miocene; (b) among Epomops, Hypsignathus, and other species of Epomophorina at the Pliocene–Pleistocene boundary; and (c) among Myonycteris species in the Early Pleistocene. Within the Epomophorini, Stenonycteris lanosus emerged first, suggesting that lingual echolocation may have appeared in the common ancestor of Epomophorini and Rousettini. Our analyses suggest that multiple events of mtDNA introgression occurred within the Epomophorus species complex during the Pleistocene.     

First record of an Australian fruit bat (Megachiroptera: Pteropodidae) reaching New Zealand

A red fruit bat (Pteropus scapulatus Peters, 1862) was picked up freshly dead after hitting power lines in a storm in Hamilton East, North Island, between 1927 and 1929 and kept, stuffed, on a Waikato farm. Unusually large southerly migrations of the red fruit bat into New South Wales and Victoria occurred for a few years after the severe drought in Queensland in 1926–27. This specimen may have been on migration, and blown across the Tasman by a storm. This is the first confirmed record of an Australian bat reaching New Zealand alive in European times.     

Conflict and congruence in a combined DNA–morphology analysis of megachiropteran bat relationships (Mammalia: Chiroptera: Pteropodidae)

The phylogeny of megabats (Mammalia: Chiroptera: Megachiroptera) has been addressed only on molecular grounds, as little effort has previously been made to describe the impressive morphological variation of the group in terms of phylogenetically informative characters. Here we provide a morphological matrix of 236 characters from the integument, dentition, cranial and post‐cranial skeleton, digestive apparatus and urogenital system. This data set covers most characters discussed previously in more restricted taxonomic contexts, as well a large number of new characters. Our aim was to generate a phylogenetic hypothesis for megabats based on a combined analysis of morphological characters and available gene sequence data from four mitochondrial and one nuclear loci. We used direct optimization under conventional equal costs, as well as under a cost ratio that maximizes homology when inapplicables (gaps) are present. Our results contradict the allegedly high level of conflict between the molecular and morphological partitions. We found that, although morphology alone recovered trees different and to some extent incompatible with those from previous molecular analyses, the combination of the two sources of evidence easily accommodated the morphological and molecular signals, yielding a resolved and relatively well‐supported phylogeny of Megachiroptera that is in reasonable agreement with the current morphology‐based taxonomy of the group. Overall congruence favored the maximization of homology by a narrow margin. In addition, partial analyses showed that implied weighting of morphology performed slightly better than equal weighting with respect to the combined analyses. © The Willi Hennig Society 2005.     

Rodrigues fruit bats (<Emphasis Type="Italic">Pteropus rodricensis</Emphasis>, Megachiroptera: Pteropodidae) retain genetic diversity despite population declines and founder events

Fruit bats of the genus Pteropus are important contributors to ecosystem maintenance on islands through their roles as pollinators and seed dispersers. However, island faunas are the most prone to extinction and there is a real need to assess the possible genetic implications of population reductions in terms of extinction risk. An effective method of ameliorating extinction risk in endangered species is the establishment of captive populations ex situ. The effectiveness of captive breeding programmes may be assessed by comparing the genetic variability of captive colonies to that of wild counterparts. Here, we use polymorphic microsatellite loci to assess genetic variability in wild, critically endangered Rodrigues fruit bats (Pteropus rodricensis, Dobson 1878) and we compare this variability to that in a captive colony. We document remarkable conservation of genetic variability in both the wild and captive populations, despite population declines and founder events. Our results demonstrate that the wild population has withstood the negative effects of population reductions and that captive breeding programmes can fulfil the goals of retaining genetic diversity and limiting inbreeding.     

Multiple levels of allopatric divergence in the endemic Philippine fruit bat Haplonycteris fischeri (Pteropodidae)

As part of a larger comparative phylogeographical study of Philippine fruit bats, I used fragments of the mitochondrial genes cytochrome  b and ND2 to investigate phylogeography and diversification in Haplonycteris fischeri , a pteropodid bat endemic to the Philippines but widespread within the archipelago. Genetic diversity in H. fischeri was extremely high in these commonly studied genes, with 101 unique haplotypes in 123 sequenced individuals, although small, continuously isolated islands had less diversity than had large island complexes. Seven monophyletic groups and one paraphyletic group were restricted to individual islands, groups of islands, or parts of islands. Each Pleistocene island complex had a single resident monophyletic lineage; these five groups were separated by approximately 6–8% sequence divergence and apparently have been diverging for 4–6 Myr. Within island groups, monophyletic lineages on some individual islands suggest that current ocean channels have also been barriers to gene flow; in some cases, multiple allopatric clades were present on single islands. Basal divergence dates were estimated to be in the early Pliocene, and most diversification was apparently connected to the ongoing geological evolution of the Philippines. Geological history and current geography interact with ecology to cause substantial genetic differentiation within this primary forest-specialist species.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 329–349.     

The hormonal and behavioral response to group formation, seasonal changes, and restraint stress in the highly social Malayan Flying Fox (Pteropus vampyrus) and the less social Little Golden-mantled Flying Fox (Pteropus pumilus) (Chiroptera: Pteropodidae)

This study examined behavioral and physiological responses (changes in inter-animal spacing, total glucocorticoids, testosterone, and body mass) to the formation of breeding and same-sex groups in two bat species, the socially gregarious Malayan Flying Fox (Pteropus vampyrus) and the less social Little Golden-mantled Flying Fox (Pteropus pumilus). We hypothesized that social instability, especially in the breeding groups and especially in P. vampyrus, would result in elevated glucocorticoids and that social facilitation of breeding and/or male-male competition would result in persistently higher levels of testosterone in breeding males. Seasonal rhythms in all measures were also predicted, and the glucocorticoid stress response was expected to vary by sex, season, and group type. Nearly all animals responded to group formation with elevated glucocorticoids, but, for breeding animals (especially aggressive male P. vampyrus), these responses persisted over time. In both species, breeding group formation resulted in elevated testosterone in males. Glucocorticoids, testosterone, testes volume, and body mass generally peaked in the breeding season in males (late summer and early autumn), but the seasonal glucocorticoid peak in females occurred in late winter and early spring. All animals responded to restraint stress with elevations in glucocorticoids that largely did not differ by sex, time of year, reproductive condition, group type, or, in lactating females, the presence of her pup. Changes in both behavior and physiology were more evident in P. vampyrus than in P. pumilus, and we believe that their underlying social differences influenced their responses to group formation and to the changing seasonal environment.     

Erythrocyte metabolism in two species of bats: common bent-wing bat (Miniopterus schreibersii) and red fruit bat (Pteropus scapulatus).

1. Metabolic intermediates, substrate utilization and enzyme activities were determined in the red blood cells of the common bent-wing bat and the red fruit bat. Standard haematological parameters and oxy-haemoglobin dissociation curves were also determined in both species. 2. The glycolytic rate as measured by lactate production was much higher for all substrates in the bent-wing bats. The activities of the glycolytic enzymes were also much higher in this species. 3. The standard haematological parameters were similar for the two species. The levels of 2,3-diphosphoglycerate (DPG) in the red cells of the fruit bat were nearly twice as high as those in the bent-wing bats. 4. The oxy-haemoglobin dissociation curve for the red fruit bat was located to the right of that for the bent-wing bat and both these curves were located to the right of that normally seen for human blood. 5. Both species of bat show blood characteristics well adapted to carrying the increased oxygen demands of flight.     

Rapid GLUT-1 mediated glucose transport in erythrocytes from the grey-headed fruit bat (Pteropus poliocephalus)

D-Glucose entry into erythrocytes from adult grey-headed flying fox fruit bats (Pteropus poliocephalus) was rapid and showed saturation at high substrate concentrations. Kinetic parameters were estimated from the concentration dependence of initial rates of zero-trans D-glucose entry at 5.5 degrees C as Michaelis constant (K(m)) 1. 64+/-0.56 mM, and maximal velocity (V(max)) 1162+/-152 micromol.l. cell water(-1).min(-1). D-Glucose entry was inhibited by cytochalasin B; mass law analysis of D-glucose-displaceable cytochalasin B binding gave values of K(d) 37.1+/-5.0 nM and B(max) 361.2+/-9.1 pmol/mg membrane protein. Entry of 2-deoxy-D-glucose, and 3-O-methyl-D-glucose, into P. poliocephalus red cells was rapid, entry of D-fructose was very slow. Glucose transporter polypeptides were identified on immunoblots as a band M(r) 47000-54000 and their identity confirmed by D-glucose-sensitive photolabeling of membranes with [3H]-cytochalasin B. Peptide-N-glycanase F digestion of both human and bat erythrocyte membranes generated GLUT-1-derived bands M(r) 37000. Trypsin digestion of human and fruit bat erythrocyte membranes generated fragmentation patterns consistent with similar GLUT-1 polypeptide structures in both species. Erythrocytes from adult Australian ghost bats (Macroderma gigas), a carnivorous microchiropteran bat, also expressed high levels of GLUT-1.