Greater Short-nosed Fruit Bat Research Articles

Anatomy and homology of the caudal auricular muscles in greater short-nosed fruit bat (Cynopterus sphinx).

Bats can be phylogenetically classified into three major groups: pteropodids, rhinolophoids, and yangochiropterans. While rhinolophoids and yangochiropterans are capable of laryngeal echolocation, pteropodids lack this ability. Delicate ear movements are essential for echolocation behavior in bats with laryngeal echolocation. Caudal auricular muscles, especially the cervicoauricularis group, play a critical role in such ear movements. Previously, caudal auricular muscles were studied in three species of bats with laryngeal echolocation, but to our knowledge, there have been no studies on non-laryngeal echolocators, the pteropodids. Here, we describe the gross anatomy of the cervicoauricularis muscles and their innervation in Cynopterus sphinx by using diffusible iodine-based contrast-enhanced computed tomography and 3D reconstructions of immunohistochemically stained serial sections. A previous study on bats with laryngeal echolocation reported that rhinolophoids have four cervicoauricularis muscles and yangochiropterans have three. We observed three cervicoauricularis muscles in the pteropodid C. sphinx. The number of cervicoauricularis muscles and their innervation pattern were comparable to those of non-bat boreoeutherian mammals and yangochiropterans, suggesting that pteropodids, and yangochiropterans maintain the general condition of boreoeutherian mammals and that rhinolophoids have a derived condition. The unique nomenclature had been previously applied to the cervicoauricularis muscles of bats with laryngeal echolocation, but given the commonality between non-bat laurasiatherians and bats, with the exception of rhinolophoids, maintaining the conventional nomenclature (i.e., M. cervicoauricularis superficialis, M. cervicoauricularis medius, and M. cervicoauricularis profundus) is proposed for bats.

IMPACT OF FRUIT BATS (Rousettus leschenaulti AND Cynopterus sphinx) IN THE TROPICAL ECOSYSTEM OF TIRUNELVELI DISTRICT, TAMIL NADU, INDIA

Fruit bat diversity available in the ecosystem of Tirunelveli District is important for pollinating flowers and seed dispersal. Two common megachiropterans Rousettus leschnaulti (fulvous fruit bat) and Cynopterus sphinx (greater short-nosed fruit bat) interacting in different agro and tropical forest ecosystem of Tirunelveli district has been selected as study animals for this impact analysis. Various food selections, processing strategies, the economical and ecological importance of bat dependent plants have provided a glimpse on the fruit bat’s bio-agent role in the ecosystem. Identification of left outs from the feeding roosts, observations with video recording and mist-netting in the foraging areas is the documented data for fruit bat–plant interdependence. Their species specific dietary preferences immensely help to retain the community structures and long time survival of specific taxa in the ecosystem. In spite of their special role they have attracted little recognition under Indian government legislations and policies. The documented species specific impact and ecosystem services of R. leschnaulti and C. sphinx in the Tropical ecosystem is the field proof data which can be of use to revise the status of fruit bats under Schedule V, Indian Wildlife Protection Act 1972.

First record of predation of a fruit bat by the Malabar Grey Hornbill (Ocyceros griseus) from southern Western Ghats, India

Consumption of bats (chiropterophagy) is globally known in 237 bird species. However, bat predation by a non-raptor is rarely observed. Here, we report a predation event by an endemic Malabar Grey Hornbill (Ocyceros griseus) on a Greater short-nosed fruit bat (Cynopterus sphinx) in Western Ghats, a biodiversity hotspot in southern India. This opportunistic record, and other published instances of animal consumption by this hornbill, suggests that such predation activity may be more prevalent during their breeding season.

Male Chemical Signalling to Recruit Females in the Greater Short-Nosed Fruit Bat Cynopterus sphinx

Mate attraction via chemosignalling is common in group-living mammals. In the greater short-nosed fruit bats, Cynopterus sphinx, it remains unclear whether males use chemosignals to attract females. Here, we use field observations to describe patterns of male chemosignalling in this species, then use preference test in captivity to infer the function of chemosignals. We observed that males engage in chemosignalling through wing fanning after marking their leaf ‘tent' roosts with saliva. The male fanned each wing alternatively and vigorously and performed frequent tongue flicks to the wing membrane. Such behaviour is exhibited towards females that returned to the tent. Afterwards, the male embraced the female with both wings. Wing fanning and tent marking occurred more often during the mating season than the non-mating season. To infer the role of chemosignals in recruiting females, we performed two different choice tests. In the first test, we tested whether females preferred the tent containing cotton balls that were rubbed gently and repeatedly on the ventral side of the plagiopatagium of the male, versus a control tent without any conspecific odour. In the second test, we tested whether females preferred a tent that was marked by a male's saliva versus a control tent without such markings. The result of both tests indicated that females recognized the saliva and ‘scent’ from the wings of males, since females always preferred tents with male chemosignals over the controls. Our findings suggest that the recruitment of females and subsequent formation of a harem in the greater short-nosed fruit bats is influenced by male chemosignals.

Activity-dependent expression of miR-132 regulates immediate-early gene induction during olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx

The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation.

Comparative inner ear transcriptome analysis between the Rickett’s big-footed bats (Myotis ricketti) and the greater short-nosed fruit bats (Cynopterus sphinx)

BackgroundBats have aroused great interests of researchers for the sake of their advanced echolocation system. However, this highly specialized trait is not characteristic of Old World fruit bats.ResultsTo comprehensively explore the underlying molecular basis between echolocating and non-echolocating bats, we employed a sequence-based approach to compare the inner ear expression difference between the Rickett’s big-footed bat (Myotis ricketti, echolocating bat) and the Greater short-nosed fruit bat (Cynopterus sphinx, non-echolocating bat). De novo sequence assemblies were developed for both species. The results showed that the biological implications of up-regulated genes in M. ricketti were significantly over-represented in biological process categories such as ‘cochlea morphogenesis’, ‘inner ear morphogenesis’ and ‘sensory perception of sound’, which are consistent with the inner ear morphological and physiological differentiation between the two bat species. Moreover, the expression of TMC1 gene confirmed its important function in echolocating bats.ConclusionOur work presents the first transcriptome comparison between echolocating and non-echolocating bats, and provides information about the genetic basis of their distinct hearing traits.

A Test for Sex-Biased Dispersal inCynopterus sphinx: Inferences from Microsatellite Markers and Mitochondrial DNA

The greater short-nosed fruit bat (Cynopterus sphinx) is a social species, widely distributed in southern Asia. We used microsatellite and mfDNA markers to assess whether this fruit bat has a sex biased dispersal pattern. We also assessed signatures of sex-biased migration using microsatellite data. No significant heterozygosity deficiency (FIS), lower assignment value (mAIc) and variance of assignment (vAIc) were found between females and males, which does not support the hypothesis that dispersal in C. sphinx is sex biased. When microsatellite genotype frequency and mfDNA haplotype distribution patterns were subjected to the AMOVA, we found that genetic partitioning was higher at mfDNA (ΦST) than autosomal markers (FST) in both sexes. There is a higher value for males than females in both the mtDNA and microsatellite data, and both adult males and females also exhibited more variation within than among populations, but without significant results. Our results indicated that C. sphinx displayed various s...

Contrasting genetic structure in two co-distributed species of old world fruit bat.

The fulvous fruit bat (Rousettus leschenaulti) and the greater short-nosed fruit bat (Cynopterus sphinx) are two abundant and widely co-distributed Old World fruit bats in Southeast and East Asia. The former species forms large colonies in caves while the latter roots in small groups in trees. To test whether these differences in social organization and roosting ecology are associated with contrasting patterns of gene flow, we used mtDNA and nuclear loci to characterize population genetic subdivision and phylogeographic histories in both species sampled from China, Vietnam and India. Our analyses from R. leschenaulti using both types of marker revealed little evidence of genetic structure across the study region. On the other hand, C. sphinx showed significant genetic mtDNA differentiation between the samples from India compared with China and Vietnam, as well as greater structuring of microsatellite genotypes within China. Demographic analyses indicated signatures of past rapid population expansion in both taxa, with more recent demographic growth in C. sphinx. Therefore, the relative genetic homogeneity in R. leschenaulti is unlikely to reflect past events. Instead we suggest that the absence of substructure in R. leschenaulti is a consequence of higher levels of gene flow among colonies, and that greater vagility in this species is an adaptation associated with cave roosting.

Role of olfactory bulb serotonin in olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae)

The role of olfactory bulb (OB) serotonin [5-hydroxytryptamine (5-HT)] in olfactory learning and memory was tested in the greater short-nosed fruit bat, Cynopterus sphinx (family Pteropodidae). Graded concentrations (25, 40, and 60 μg) of 5,7-dihydroxytryptamine (5,7-DHT) or saline were injected into the OB of bats one day before training to the novel odor. In a behavioral test, 5,7-DHT (60 μg) injected bats made significantly fewer feeding attempts and bouts when compared to saline-injected bats during learning and in the memory test. Subsequent biochemical analysis showed that 5-HT level was effectively depleted in the OB of 5,7-DHT injected bats. To test odor-induced 5-HT mediated changes in 5-HT receptors and second messenger cascade in the OB, we examined the expression of 5-HT receptors and mitogen-activated protein kinase (MAPK)/Erk cascade after training to the novel odor. We found that odor stimulation up-regulated the expression of 5-HT 1A receptor, Erk1 and Creb1 mRNA, and phosphorylation of ERK1 and CREB1. Odor stimulation failed to induce expression in 5-HT-depleted bats, which is similar to control bats and significantly low compared to saline-treated bats. Together these data revealed that the level of 5-HT in the OB may regulate olfactory learning and memory in C. sphinx through Erk and CREB.

Characterization of the sleep architecture in two species of fruit bat

Bats (Chiroptera) are the second-most abundant mammalian order in the world, occupying a diverse range of habitats and exhibiting many different life history traits. In order to contribute to this highly underrepresented group we describe the sleep architecture of two species of frugivorous bat, the greater short-nosed fruit bat ( Cynopterus sphinx) and the lesser dawn fruit bat ( Eonycteris spelaea). Electroencephalogram (EEG) and electromyogram (EMG) data were recorded from multiple individuals (≥5) by telemetry over a 72-h period in a laboratory setting with light/dark cycles equivalent to those found in the wild. Our results show that over a 24-h period both species spent more time asleep than awake (mean 15 h), less than previous reported for Chiroptera (20 h). C. sphinx spent significantly more of its non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM) quotas during the light phase, while E. spelaea divided its sleep–wake architecture equally between both light and dark phases. Comparing the sleep patterns of the two species found that C. sphinx had significantly fewer NREM and REM episodes than E. spelaea but each episode lasted for a significantly longer period of time. Potential hypotheses to explain the differences in the sleep architecture of C. sphinx with E. spelaea, including risk of predation and social interaction are discussed.

Feeding Habits of <I>Cynopterus sphinx</I> in Guangzhou Area

Greater short-nosed fruit bat (Cynopterus sphinx) is an abundant species of fruit-eating bats widely distributed in the Guangzhou area. From May 2004 to April 2006, the feeding habits of Cynopterus sphinx were studied using field surveys, gleaning and feces analysis. Analysis of 26 feces and leftovers of Cynopterus sphinx showed that Cynopterus sphinx had eaten fruits from 21 plant species belonging to 13 families and leaves of 3 species belonging to 3 families. The main food of Cynopterus sphinx are fruits of Moraceae ficus, Syzygium jambos, Livistona subglobosa and Livistona subglobosa. The feeding habits of Cynopterus sphinx changed seasonally, as it mainly ate various kinds of fruits in summer and autumn, but seeds of Livistona subglobosa in winter and spring. The reproduction fastigium of Cynopterus sphinx in Guangzhou area is from May to October.