Short-nosed Fruit Bat Cynopterus Sphinx Research Articles

Olfactory learning and memory in the greater short-nosed fruit bat Cynopterus sphinx: the influence of conspecifics distress calls.

This study was designed to test whether Cynopterus sphinx distress calls influence olfactory learning and memory in conspecifics. Bats were exposed to distress calls/playbacks (PBs) of distress calls/modified calls and were then trained to novel odors. Bats exposed to distress calls/PBs made significantly fewer feeding attempts and bouts of PBs exposed to modified calls, which significantly induced the expression of c-Fos in the caudomedial neostriatum (NCM) and the amygdala compared to bats exposed to modified calls and trained controls. However, the expression of c-Fos in the hippocampus was not significantly different between the experimental groups. Further, protein phosphatase-1 (PP-1) expression was significantly lower, and the expression levels of E1A homologue of CREB-binding protein (CBP) (P300), brain-derived neurotrophic factor (BDNF) and its tyrosine kinase B1 (TrkB1) receptor were significantly higher in the hippocampus of control/bats exposed to modified calls compared to distress calls/PBs of distress call-exposed bats. Exposure to the call possibly alters the reciprocal interaction between the amygdala and the hippocampus, accordingly regulating the expression levels of PP1, P300 and BDNF and its receptor TrkB1 following training to the novel odor. Thus, the learning and memory consolidation processes were disrupted and showed fewer feeding attempts and bouts. This model may be helpful for understanding the contributions of stressful social communications to human disorders.

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.

Morphometric and Phylogenetic Analysis of Short-Nosed Fruit Bat Cynopterus sphinx (Vahl, 1797) Captured from Fata Regions, Pakistan

Morphometric and Phylogenetic Analysis of Short-Nosed Fruit Bat Cynopterus sphinx (Vahl, 1797) Captured from Fata Regions, Pakistan

Report on three ectoparasites of the Greater Short-nosed Fruit Bat Cynopterus sphinx Vahl, 1797 (Mammalia: Chiroptera: Pteropodidae) in Cachar District of Assam, India

Ectoparasites of bats (Chiroptera: Pteropodidae), with a description of three species of of which two belong to order Mesostigmata (family: Ameroseiidae and Macronyssidae) and one belong to order Ixodida (family: Ixodidae), from northeastern India are discussed. The present study was carried out for six months (January–June 2014) to identify the various ectoparasites of the Short-nosed Fruit Bat Cynopterus sphinx in Cachar District of Assam, northeastern India. A total of 12 individuals of C. sphinx was captured using mist nets from eight different localities of the study area. During the study, a total of 125 parasites was collected from C. sphinx. The identified parasites were Dermacentor sp. Indet., Ameroseius sp. Indet., and Steatonyssus sp. Indet. and falls under the class Arachnida.

MiR-132 regulated olfactory bulb proteins linked to olfactory learning in greater short-nosed fruit bat Cynopterus sphinx

Earlier, we showed that micro RNA-132 (miR-132) regulate the immediate early genes (IEGs) in the olfactory bulb (OB) of fruit bat Cynopterus sphinx during olfactory learning. This study was designed to examine whether the miR-132 regulate other proteins in OB during olfactory learning. To test this, miR-132 anti-sense oligodeoxynucleotide (AS-ODN) was delivered to the OB and then trained to novel odor. The 2-dimensional gel electrophoresis analysis showed that inhibition of miR-132 altered olfactory training induced expression of 321 proteins. Further, liquid chromatography-mass spectrometry (LC-MS/MS) analysis reveals the identity of differently expressed proteins such as phosphoribosyl transferase domain containing protein (PRTFDC 1), Sorting nexin-8 (SNX8), Creatine kinase B-type (CKB) and Annexin A11 (ANX A11). Among them PRTFDC 1 showing 189 matching peptides with highest sequence coverage (67.0%) and protein-protein interaction analysis showed that PRTFDC 1 is a homolog of hypoxanthine phosphoribosyltransferase-1 (HPRT-1). Subsequent immunohistochemical analysis (IHC) showed that inhibition of miR-132 down-regulated HPRT expression in OB of C. sphinx. In addition, western blot analysis depicts that HPRT, serotonin transporter (SERT), N-methyl-d-asparate (NMDA) receptors (2A,B) were down-regulated, but not altered in OB of non-sense oligodeoxynucleotide (NS-ODN) infused groups. These analyses suggest that miR-132 regulates the process of olfactory learning and memory formation through SERT and NMDA receptors signalling, which is possibly associated with the PRTFDC1-HPRT interaction.

Odour discrimination learning in the Indian greater short-nosed fruit bat (Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus.

Activity-dependent expression of immediate-early genes (IEGs) is induced by exposure to odour. The present study was designed to investigate whether there is differential expression of IEGs (Egr-1, C-fos) in the brain region mediating olfactory memory in the Indian greater short-nosed fruit bat, Cynopterus sphinx We assumed that differential expression of IEGs in different brain regions may orchestrate a preference odour (PO) and aversive odour (AO) memory in C. sphinx We used preferred (0.8% w/w cinnamon powder) and aversive (0.4% w/v citral) odour substances, with freshly prepared chopped apple, to assess the behavioural response and induction of IEGs in the olfactory bulb, hippocampus and amygdala. After experiencing PO and AO, the bats initially responded to both, later only engaging in feeding bouts in response to the PO food. The expression pattern of EGR-1 and c-Fos in the olfactory bulb, hippocampus and amygdala was similar at different time points (15, 30 and 60 min) following the response to PO, but was different for AO. The response to AO elevated the level of c-Fos expression within 30 min and reduced it at 60 min in both the olfactory bulb and the hippocampus, as opposed to the continuous increase noted in the amygdala. In addition, we tested whether an epigenetic mechanism involving protein phosphatase-1 (PP-1) acts on IEG expression. The observed PP-1 expression and the level of unmethylated/methylated promoter revealed that C-fos expression is possibly controlled by odour-mediated regulation of PP-1. These results in turn imply that the differential expression of C-fos in the hippocampus and amygdala may contribute to olfactory learning and memory in C. sphinx.

Effect of female group size on harem male roosting behavior of the Indian short-nosed fruit bat Cynopterus sphinx

Mate guarding has been known to incur costs and cause constraints for harem males in many polygynous species. However, the effect of female group size on the harem male’s time budget in bats has received very limited attention. The Indian short-nosed fruit bat, Cynopterus sphinx, exhibits resource defense polygyny, in which tent roosting males construct tents and defend multiple female bats. We studied the effect of female group size on three aspects of harem male behavior: social grooming by reciprocal licking, tent maintenance, and tent guarding in the mast tree Polyalthia longifolia. In the process of reciprocal licking, all the bats in the harem were drenched in saliva before emergence, and this activity was positively and significantly correlated with female group size. Once females departed for foraging, harem males remained in their respective tents at night-time between intermittent foraging bouts and engaged in tent maintenance and tent guarding. Time invested by harem male bats in tent maintenance and tent guarding were positively and significantly correlated with female group size. Harem males extended their presence in tent by utilizing tents as feeding roosts. Female group size also influenced the emergence time of harem male bats, where males with largest group emerged later than did the smallest group. Likewise, harem male with the smallest group had more time available for foraging than the male with the largest group. Findings of this study suggest that having a larger harem may indeed be costly for the males by reducing their foraging time.

Foraging of the Indian Short-nosed Fruit Bat Cynopterus sphinx on banana in shops and on the pieces dropped by monkeys at a temple

The Indian Short-nosed Fruit Bat Cynopterus sphinx fed on the pieces of banana fruit that were dropped by monkeys on the tower of a temple and in nearby shops. The monkeys obtained fruits from devotees and shop owners. The peak number of bat visits occurred during pre- and post- midnight hours at the tower and shops, respectively, coinciding with the lights off situation and reduced human disturbance. The bats landed on bunches of ripe bananas hanging in the front of shops. The number of bat landings on the tower was greater than that in the shops. The overall number of bat visits were higher during October when compared to other periods of the year. This may be due to the occurrence of more festivals during October. Our study is an example of opportunistic feeding, in which banana pieces dropped while monkeys were feeding on them were eaten by the bats.

A Novel Food Preference in the Greater Short-Nosed Fruit Bat,Cynopterus sphinx: Mother-Pup Interaction a Strategy for Learning

The greater short-nosed fruit bat Cynopterus sphinx relies on the diverse food resources available in its habitat, with individuals identifying and discriminating between food sources using their sense of smell, in relation to volatile compounds released from fruit, flowers and leaves. The work detailed in this article tested whether pups learn about novel food from interactions with their mothers during foraging and develop preferences. Mother-pup pairs or pups alone were trained during postnatal days (PND) 46–50 using Mangifera indica as a novel fruit. They were then tested during PND 61–65 for food preferences in relation to a known fruit (Achras sapota) and the novel fruit (M. indica). When the trained pups and untrained pups were tested for food preferences independently, those trained with the mother were found to exhibit significantly more marked preferences for the novel fruit as compared with either the pups trained without their mothers or the untrained pups. They made a greater number of feeding attempts and bouts in respect of the novel fruit. However, pups trained without their mothers and untrained pups also both showed a response to the novel fruit during the later period of testing. The results suggest that mother-pup interactions during the early foraging period may provide an opportunity for C. sphinx pups to learn about novel food sources thanks to their mother. Later they may learn independently on the basis of experience from mother's milk and/or social interaction with conspecifics.

Structure of distress call: implication for specificity and activation of dopaminergic system.

We conducted a set of playback experiments aimed at understanding whether distress-call structure in the greater short-nosed fruit bat Cynopterus sphinx is specific in encoding information relating to stress that attracts conspecifics. We tested the specificity by playing their distress call and its modified version at a foraging site for free-ranging bats, as well as under captive conditions involving either a small group or individuals. In a separate playback experiment, bats showed a significantly greater response when the natural call as opposed to a modified call was played back to captive as well as free-ranging bats at the foraging site. Under captive conditions, bats showed less of a response to the playback of distress calls when in a group than when alone. We subsequently found that tyrosine hydroxylase (TH) and its transcription factor-nuclear receptor related factor 1 (Nurr-1); and the dopamine transporter (DAT) and its receptor (D1DR) were elevated significantly in the amygdala of bats both emitting and responding to a distress call, but not in the case of bats responding to the modified call. These results suggest that distress-call structure encodes information on the state of stress that is capable of being conveyed to conspecifics.

Distress calls of the greater short-nosed fruit bat Cynopterus sphinx activate hypothalamic-pituitary-adrenal (HPA) axis in conspecifics

In a stressful situation, greater short-nosed fruit bats (Cynopterus sphinx) emit audible vocalization either to warn or to inform conspecifics. We examined the effect of distress calls on bats emitting the call as well as the bats receiving the distress signal through analysis of the hypothalamic-pituitary-adrenal axis and catacholaminargic systems. We measured the levels of neurotransmitters [serotonin (5-HT), dopamine (DA), norepinephrine (NE)] and stress hormones [(adrenocorticotropic hormone (ACTH) and corticosterone (CORT)]. Our results showed that distress call emission elevated the level of ACTH and CORT, as well as 5-HT, DA and NE in the amygdala, for both the call emitting bat and the responding bat. Subsequently, we observed increased activity of glucocorticoid receptor and its steroid receptor co-activator (SRC-1). An expression of SRC-1 was up-regulated in the distress call emitter only, whereas it was at a similar level in both the call responder and silent bats. These findings suggest that bats emitting distress calls and also bats responding to such calls have similar neurotransmitter expression patterns, and may react similarly in response to stress.

Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx

Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation.

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...

Dietary energy estimate inferred from fruit preferences of Cynopterus sphinx (Mammalia: Chiroptera: Pteropodidae) in a flight cage in tropical China

From a conservation standpoint, inferences about dietary intake are much more robust when placed within a demographic, temporal and nutritional context. We investigated the dietary cornerstones of fruit preference and the dietary energy gained in the Short-nosed Fruit Bat Cynopterus sphinx. Feeding trials were conducted with 15 wild-caught bats kept in a large flight cage in Xishuangbanna, Yunnan, China, over nine weeks. The goal was to estimate the amount of food required for the sustenance of C. sphinx in captivity and calculate the food amount in terms of energy. Of the fruits (apple, banana, pear, papaya and guava) offered, apple (89%) and banana (93%) were found to be preferred. The relative consumption of fruit species tended to be positively correlated with the energy value per gram fruit. Banana (93%) was the most preferred and papaya (47%) the least preferred of the offered fruits. The results suggest that the minimum recommended dietary intake is 214-267 kJ per day for an individual of C. sphinx in captivity with conditions allowing flight. From this, we can assume that the same energy requirements may represent the minimum intake for bats in the wild. Both body mass and food consumption decreased significantly when bats were kept in a small cage.

Bat Foraging Strategies and Pollination ofMadhuca latifolia(Sapotaceae) in Southern India

The sympatrically occurring Indian short-nosed fruit bat Cynopterus sphinx and Indian flying fox Pteropus giganteus visit Madhuca latifolia (Sapotaceae), which offers fleshy corollas (≈ 300 mg) to pollinating bats. The flowers are white, tiny and in dense fascicles. The foraging activities of the two bat species were segregated in space and time. Cynopterus sphinx fed on resources at lower heights in the trees than P. giganteus and its peak foraging activity occurred at 19:30 h, before that of P. giganteus. Foraging activities involved short searching flights followed by landing and removal of the corolla by mouth. Cynopterus sphinx detached single corollas from fascicles and carried them to nearby feeding roosts, where it sucked the juice and spat out the fibrous remains. Pteropus giganteus landed on top of the trees and fed on the corollas in situ; its peak activity occurred at 20:30 h. This species glided and crawled between the branches and held the branches with claws and forearms when removing fleshy corollas with its mouth. Both C. sphinx and P. giganteus consumed fleshy corollas with attached stamens and left the gynoecium intact. Bagging experiments showed that fruit-set in bat-visited flowers was significantly higher (P < 0.001) than in self-pollinated flowers.

Fellatio by fruit bats prolongs copulation time.

Oral sex is widely used in human foreplay, but rarely documented in other animals. Fellatio has been recorded in bonobos Pan paniscus, but even then functions largely as play behaviour among juvenile males. The short-nosed fruit bat Cynopterus sphinx exhibits resource defence polygyny and one sexually active male often roosts with groups of females in tents made from leaves. Female bats often lick their mate's penis during dorsoventral copulation. The female lowers her head to lick the shaft or the base of the male's penis but does not lick the glans penis which has already penetrated the vagina. Males never withdrew their penis when it was licked by the mating partner. A positive relationship exists between the length of time that the female licked the male's penis during copulation and the duration of copulation. Furthermore, mating pairs spent significantly more time in copulation if the female licked her mate's penis than if fellatio was absent. Males also show postcopulatory genital grooming after intromission. At present, we do not know why genital licking occurs, and we present four non-mutually exclusive hypotheses that may explain the function of fellatio in C. sphinx.

Do fruit bats deserve to be listed as vermin in the Indian Wildlife (Protection) &amp; Amended Acts? A critical review

Of the 13 species of fruit bats occurring in India, the Indian flying fox Pteropus giganteus, the dog-faced fruit bat Rousettus leschenaultii and the greater short-nosed fruit bat Cynopterus sphinx are distributed throughout the country. They usually live in trees (P. giganteus), temples and caves (R. leschenaultii) and foliage (C. sphinx) and feed on fruits such as fig Ficus spp., Singapore cherry Muntingia calabura, Indian almond Terminalia catappa, mango Mangifera indica, guava Psidium guajava as well as leaves, nectar and pollen. The other 10 species live at sea level and at altitudes of > 2,000 m and their distribution and foraging activities may be restricted mainly to forests. Two of them, the Nicobar flying fox Pteropus faunulus and Salim Ali's fruit bat Latidens salimalii are endemic. Although details of their foraging activity are poorly known, there is no evidence that they visit commercial fruit orchards. They feed on wild fruits and disperse seeds widely, contributing to forest regeneration. Although P. giganteus, R. leschenaultii and C. sphinx feed on commercial fruits, their role in pollination and seed dispersal of economically important plants such as kapok Ceiba pentandra, mahua Bassia latifolia and petai Parkia spp. is important. Sacrificial crops such as M. calabura can be used at orchards to reduce the damage bats cause to commercial fruit. Because the ecological services provided by bats are not appreciated by the public and conservation planners, all fruit bat species with one exception are still categorized as vermin and included as such in Schedule V of the Indian Wildlife (Protection) Act, 1972 and amended Acts. It is now appropriate for the Government of India to revisit this issue and consider removing these pollinators and seed dispersers from the list of vermin in the Wildlife (Protection) Act.

Transition of nonharem male to harem male status in the short-nosed fruit bat Cynopterus sphinx

The short-nosed fruit bat Cynopterus sphinx is known to exhibit resource defence polygyny as its primary mating strategy. Tent construction by harem males to recruit females represents a heavy investment of time and effort, which is not done by nonharem males. The previously unobserved mode of harem formation by the solitary males was studied using mark-recapture and radio-telemetry. In our observation, the solitary males roosting near to harems started recruiting females by occupying the tent abandoned by the harems. This result suggests that the transition of nonharem male to harem male status possibly by a previously unobserved mode and the female recruitment is associated with resource (roost). It implies that the solitary males are actively involving in female recruitment and also presumably mating.

In situ feeding tactics of short-nosed fruit bat (Cynopterus sphinx) on mango fruits: evidence of extractive foraging in a flying mammal

We report a sequence of behaviors exhibited by the short-nosed fruit bat Cynopterus sphinx while feeding on fruits of Mangifera indica. They peel off the outer skin to form a feeding area of about 3–6 cm diameter. Such food preparatory behaviors were more pronounced on larger mangoes. Bats competed among themselves to feed on the mangoes that had such feeding areas exposed. Individuals that spent a considerable amount of time on food preparatory behaviors actively secured the fruits. Altogether, these behaviors indicate that Cynopterus bats might have learnt, over evolutionary time, and developed behaviors that facilitate efficient processing and feeding of fruits such as mangoes. It appears that actions exhibited by C. sphinx in peeling off the outer skin of mangoes exemplify “extractive foraging”, a behavior that is prominently known in large-brained mammals. Thus, our findings will have implications on the distribution and evolution of extractive foraging and “technical intelligence” among mammalian lineages.

Wing morphology and flight development in the short-nosed fruit bat Cynopterus sphinx

Postnatal changes in wing morphology, flight development and aerodynamics were studied in captive free-flying short-nosed fruit bats, Cynopterus sphinx. Pups were reluctant to move until 25 days of age and started fluttering at the mean age of 40 days. The wingspan and wing area increased linearly until 45 days of age by which time the young bats exhibited clumsy flight with gentle turns. At birth, C. sphinx had less-developed handwings compared to armwings; however, the handwing developed faster than the armwing during the postnatal period. Young bats achieved sustained flight at 55 days of age. Wing loading decreased linearly until 35 days of age and thereafter increased to a maximum of 12.82 N m −2 at 125 days of age. The logistic equation fitted the postnatal changes in wingspan and wing area better than the Gompertz and von Bertalanffy equations. The predicted minimum power speed ( V mp) and maximum range speed ( V mr) decreased until the onset of flight and thereafter the V mp and V mr increased linearly and approached 96.2% and 96.4%, respectively, of the speed of postpartum females at the age of 125 days. The requirement of minimum flight power ( P mp) and maximum range power ( P mr) increased until 85 days of age and thereafter stabilised. The minimum theoretical radius of banked turn ( r min) decreased until 35 days of age and thereafter increased linearly and attained 86.5% of the r min of postpartum females at the age of 125 days.