Short-tailed Bat Research Articles

Structure and composition of Nycteribiidae and Streblidae flies on bats along an environmental gradient in northeastern Brazil

Bats can be parasitized by several arthropod groups, including ectoparasitic flies. The high host specificity is a common phenomenon between flies and bats. In recent years, more efforts have been employed to understand how environmental variables can influence richness and parasitic load (PL). However, many gaps still need to be filled to better understand this issue. We analyzed the PL of flies on bats sampled in three environments with different rain volume and vegetation types to verify if PL is correlated with rainfall and if there are differences in the PL on bats within and between environments. Overall, there was no correlation between rainfall and PL in the same environment, nor a difference between the three environments. When tested separately, Seba’s short-tailed bats (Carollia perspicillata (Linnaeus, 1758)) had a difference in prevalence of flies between environments and flat-faced fruit-eating bats (Artibeus planirostris (Spix, 1823)) had a greater abundance of flies in the rainy season in a semiarid area. There was no difference in PL between male and female bats. Our results suggest that bat–fly interactions are driven by several factors, not only by the amount of rainfall or vegetation, and that different host species may respond differently with no obvious general pattern.

Experimental manipulation of reproductive tactics in Seba's short-tailed bats: consequences on sperm quality and oxidative status.

To reproduce, males have to fertilize the female’s eggs, sometimes in competition with ejaculates of other males. In species where males display alternative reproductive tactics, whereby territorial males secure mating and non-territorial males have to sneak copulations, the latter might be expected to invest relatively more resources towards sperm quality compared with the territorial males. Sperm cells are especially vulnerable to oxidative stress, which reduces male fertility. Therefore, antioxidant resources are expected to modulate sperm quality, and might be allocated differently between reproductive tactics. To test the link between reproductive tactics, redox profile and sperm quality, we experimentally induced changes in the reproductive tactics of 39 captive males Seba’s short-tailed bats Carollia perspicillata. We monitored the blood and ejaculate oxidative balance, and the sperm quality before, 7 days and 21 days after the manipulation of reproductive tactic. Although ejaculates’ oxidative damage was negatively related to sperm velocity, males exhibited similar blood and ejaculates redox profiles and similar sperm quality, regardless of their reproductive tactic. Possibly, these results arise as a consequence of some constraints having been lifted during the experiment. Our results also suggest that, in Seba’s short-tailed bats, the expression of alternative reproductive tactics is not subjected to strong oxidative constraints. Furthermore, our results could reflect an absence of trade-off between pre- and post-copulatory traits in harem males, as they could be selected to invest both in female attraction and sperm quality, as a consequence of their inability to fully monopolize females.

First cryopreservation of phyllostomid bat sperm

Bats, the second-largest mammalian order, are widely distributed and provide crucial ecosystem services. Their reproductive biology comprises noteworthy characteristics, such as long-term sperm storage, delayed implantation or even delayed fetal development. The understanding of these mechanisms remains limited. Research in reproductive biology may become crucial for the conservation of endangered bat species. Indeed, the IUCN Red List of Threatened Species currently lists 76 bat species as endangered or critically endangered, for which conservation measures should be taken. The development of assisted reproductive technologies (ART) in bats would thus open new perspectives.In this context we here describe the first successful cryopreservation of bat sperm in the Seba’s short-tailed bat (Carollia perspicillata). Epididymal sperm of 30 males was pooled in 6 sample sets and diluted using four different cryo-diluents: Canifreeze, modified Canifreeze, BotuCrio® and Test egg yolk extender. Glycerol and a mixture of glycerol and methylformamide were used as cryoprotectants. Best post-thaw results were achieved when sperm was diluted in Test egg yolk extender containing a mixture of glycerol and methylformamide as cryoprotectant. Post-thaw sperm motility, progressive motility and acrosome integrity of 42.0 ± 3.4%, 28.3 ± 6.3% and 87.7 ± 1.7%, respectively were superior to all other variants tested. It remains to be determined if the post-thaw quality of cryopreserved bat spermatozoa achieved in this study is sufficient for the use in artificial inseminations and produces acceptable pregnancy rates. Successful cryopreservation of spermatozoa in C. perspicillata may serve as the first model to establish gamete rescue programs and develop ART in other, critically endangered bat species.

Modification of sperm fatty acid composition during epididymal maturation in bats.

Biochemical properties of polyunsaturated fatty acids (PUFAs) are fundamental to sperm movements. Amongst all adjustments operated during epididymal maturation, sperm membrane lipid composition is remodelled. Specifically, the proportion of PUFAs usually increases from the caput towards the cauda epididymidis. In mammals, PUFAs are predominantly acquired through the diet, which can consequently impact male fertility. We aimed at analysing to what extent n-6 and n-3 PUFAs are incorporated into sperm in the Seba's short-tailed bat (Carollia perspicillata), and at demonstrating the effect of the sperm fatty acid composition on sperm mobility. We therefore provided food varying in fatty acid composition to males of C. perspicillata and measured the fatty acid composition and mobility traits in spermatozoa collected from the caput and cauda epididymides. We found that n-6 and n-3 PUFAs and saturated fatty acids were significantly related to sperm velocity but not to the proportion of progressive sperm (i.e. motility). Concomitant to an increase in sperm velocity, the level of fatty acid saturation increased from the caput to the cauda epididymidis, while the proportion of PUFAs remained similar along the epididymis. A reduction in n-6 PUFAs counterbalanced an increase in n-3 PUFAs. The food treatments did not affect the sperm fatty acid composition. Our results suggest that a precise endogenous control rather than dietary effects determines sperm fatty acid composition in C. perspicillata.

Cases of induced alloparental care in Seba’s short-tailed fruit bat

Alloparental care has been reported in over 120 mammalian species. Here, we describe the first observed cases of induced alloparental care in Seba’s short-tailed fruit bat ( Carollia perspicillata ) at Macaregua cave (Santander, Colombia). As a part of a reproductive study, specimens of C. perspicillata were sampled between June and August 2015. During two separate occasions, we observed the willingness of lactating females to accept and carry abandoned pups, after we put a female and a non-parental pup together. Additional data is needed to confirm adoption capacity of Seba’s short-tailed fruit bat. This is the first observation of potentially cooperative behavior in this species. Keywords: alloparenting, Chiroptera, cooperative behavior, Colombia, lactating females.

Food restriction, but not seasonality, modulates the acute phase response of a Neotropical bat

Season and food intake are known to affect immune response of vertebrates yet their effects on metabolic rate have been rarely explored. We tested the effect of season and acute food restriction and their interaction on the energetic cost of immune response activation of a tropical vertebrate, the Seba's short-tailed fruit bat (Carollia perspicillata). We specifically stimulated the acute phase response (APR) with bacterial lipopolysaccharide (LPS) to measure metabolic changes along with changes in body temperature (Tb), body mass (Mb), white blood cell counts and the Neutrophil/Lymphocyte ratio (N/L). We found no effect of season on the different factors associated to the activation of the APR. In contrast to our expectations, unfed bats reached similar Tb increments and RMR peak values and had higher RMR scope values and higher caloric costs than fed bats after LPS injection. However, food deprivation led to delayed metabolic response indicated by longer time required to reach peak RMR values in unfed bats. Both food-deprived and fed bats did not present leukocytosis after APR activation and their WBC counts were similar, but unfed bats had a significant increase of N/L. APR activation represented a small fraction of the bat daily energy requirements which might explain why unfed bats were not limited to mount a metabolic response. Our study adds to recent evidence showing that activating the innate immune system is not an energetically expensive process for plant-eating bats.

Harvest rates and foraging strategy of Carollia perspicillata (Chiroptera: Phyllostomidae) in an artificial food patch

An organism’s foraging strategy depends on its ability to acquire and use information from food patches. A forager that does not obtain information from a food patch should remain there for a fixed time or a fixed amount of harvest. Foragers that obtain partial or complete information from the patch should be able to estimate costs and benefits from its exploitation. The foraging strategy used by a forager can be determined using the giving-up density (GUD) technique. The GUD is the amount of food left by a forager after feeding in a patch with diminishing returns. We constructed an artificial feeder to examine the foraging strategy of the short-tailed fruit bat Carollia perspicillata (Chiroptera: Phyllostomidae). In this feeder, the bat’s harvest rate declined with time, i.e., they experienced diminishing returns. When offered feeders with different initial food densities, bats consumed proportionately more from rich patches than from poor ones, but they equalized GUDs. When offered feeders with different concentrations of sugar (i.e., different energy content), the higher the sugar concentration in the food, the more they consumed. Altogether, the evidence indicates that these fruit bats used complete, unbiased information to decide how much time to stay in a food patch.

Spatiotemporal and demographic variation in the diet of New Zealand lesser short-tailed bats (Mystacina tuberculata).

Variation in the diet of generalist insectivores can be affected by site‐specific traits including weather, habitat, and season, as well as demographic traits such as reproductive status and age. We used molecular methods to compare diets of three distinct New Zealand populations of lesser short‐tailed bats, Mystacina tuberculata. Summer diets were compared between a southern cold‐temperate (Eglinton) and a northern population (Puroera). Winter diets were compared between Pureora and a subtropical offshore island population (Hauturu). This also permitted seasonal diet comparisons within the Pureora population. Lepidoptera and Diptera accounted for >80% of MOTUs identified from fecal matter at each site/season. The proportion of orders represented within prey and the Simpson diversity index, differed between sites and seasons within the Pureora population. For the Pureora population, the value of the Simpson diversity index was higher in summer than winter and was higher in Pureora compared to Eglinton. Summer Eglinton samples revealed that juvenile diets appeared to be more diverse than other demographic groups. Lactating females had the lowest dietary diversity during summer in Pureora. In Hauturu, we found a significant negative relationship between mean ambient temperature and prey richness. Our data suggest that M. tuberculata incorporate a narrower diversity of terrestrial insects than previously reported. This provides novel insights into foraging behavior and ecological interactions within different habitats. Our study is the first from the Southern Hemisphere to use molecular techniques to examine spatiotemporal variation in the diet of a generalist insectivore that inhabits a contiguous range with several habitat types and climates.

The high-output singing displays of a lekking bat encode information on body size and individual identity

A growing body of research suggests that songs are an important part of the courtship behavior of many bat species, however there is little information on the basic characteristics of these vocalizations, or how they may function as a courtship signal. Lekking male lesser short-tailed bats (Mystacina tuberculata) appear to use vocal displays as a primary method for attracting mates, but it is unclear if these vocalizations constitute songs, and what characteristics females may use for mate selection. We recorded 16 lekking males and described the frequency and temporal properties of their vocalizations. We identified four notes (upsweeps, downsweeps, trills, and tones) that comprise courtship vocalizations, and males produced these notes either singly, or combined them linearly to form composite syllables. We classified 51 distinct syllable types (with an average of 29 types per male), with four (trills, upsweep-trills, trill-downsweeps, and upsweep-trill-downsweeps) comprising 69% of all syllables produced. The duration of trill-downsweeps scaled negatively with forearm length (a proxy for body size in bats), and all four main syllable types showed evidence of individuality. Based on the behavioral characteristics and contexts of these courtship vocalizations, we posit that this behavior constitutes singing. Furthermore, M. tuberculata potentially has one of the highest sustained song outputs yet described. Our results suggest the singing displays of M. tuberculata are signals that provide useful, honest cues of male characteristics and identity to females, and are as complex as the songs of many passerines.

Reproductive Pattern of the Silky Short-Tailed BatCarollia brevicauda(Chiroptera: Phyllostomidae) in the Andes of Colombia

The silky short-tailed bat (Carollia brevicauda) is common and widely distributed in the Neotropic; however, data on reproductive biology is scarce. Here, we present the results of a monitoring of two colonies in the Andes of Colombia. The high recapture rate allowed us to estimate the length of pregnancy, lactation, and between-births interval. Results showed that this species reproduced with low synchrony throughout the year and may exhibit a polyoestry reproductive pattern with oestrous postpartum that lasts around eight months. The pregnancy length was two and a half months to three months and lactation length was one and a half month to two months. Males also showed reproductive activity throughout the year. The asynchronous reproduction of this species at the study area suggests that factors related to body condition may be more important for timing of reproduction than environmental cues. The reproductive life-history traits of this species are similar to other species of the genus Carollia and Phyllostomidae family.

Dietary variation during reproduction in Seba’s short-tailed fruit bat

Energy and nutrient availability are important determinants of fetal and offspring development. Given high energy and nutrient expenditure during pregnancy and lactation, foraging strategies and choices of specific food items are critical for survival of both mother and offspring. We analyzed dietary variation and consumption of nitrogen-rich and calcium-rich foods during different developmental stages in Seba's short-tailed fruit bat (Carollia perspicillata). Dietary analysis was carried out on fecal samples from males and nonpregnant, early pregnant, late pregnant, and lactating females at Macaregua Cave in Santander, Colombia. Diets were similar among males, nonpregnant females, and pregnant females, but lactating females exhibited statistically distinguishable diets. Males and pregnant females displayed a generalist diet, eating a wide variety of items, whereas nonpregnant and lactating females had narrower diets. Nitrogen-rich items, such as Piper (Piperales: Piperaceae; pepper plants) and insects, were not prevalent in the diet of pregnant bats, whereas spiked pepper exceeded expected frequencies in the diets of lactating bats. Calcium-rich Ficus (Rosales: Moraceae; figs) was rarely found in the diets of lactating or pregnant bats. Increased calcium requirements associated with lactation may therefore be satisfied through other avenues.

Courtship behaviour and display-site sharing appears conditional on body size in a lekking bat

Leks are aggregations of sexually displaying males visited by receptive females and characterized by intense male–male competition to attract mates. Success in lekking species is often contingent upon male display output and/or lek attendance, with energetically costly displays functioning as an honest indicator of male quality. Furthermore, display spaces are vigorously defended by territorial males, and territory characteristics are often linked to male phenotype. Here we describe the courtship and territorial behaviour of lekking lesser short-tailed bats, Mystacina tuberculata, and both behaviours appear to be conditional on body size. During the breeding season, lekking males occupy and defend small tree hollows and sing for long periods of the night to attract females. Although some males sing alone, others form ‘timeshare’ singing roosts, where multiple males visit sequentially to sing each night. In our study, solitary males were significantly smaller than timeshare males and individually had both higher song outputs and higher roost occupancy rates, although timeshare roosts had higher overall occupancy rates. There appeared to be no fitness difference between the two male groups, and while one timeshare roost contained relatively closely related individuals (which roost settlement simulations indicate was not a chance event), four did not. We discuss factors that may promote timeshare formation, including competition for access to desired roosts and potential by-product mutualisms. Courtship and sexual selection in bats is largely undescribed, and thus our study provides a useful description of behaviour in a little-studied taxon.

Bone Marrow in the Hyatid Bones and Nasal Turbines of Captive, Short-tailed Fruit Bats

Bone Marrow in the Hyatid Bones and Nasal Turbines of Captive, Short-tailed Fruit Bats

Weather and demographics affect Dactylanthus flower visitation by New Zealand lesser short-tailed bats

Weather and demographics affect Dactylanthus flower visitation by New Zealand lesser short-tailed bats

NewAnenterotremaStunkard, 1938 (Digenea: Anenterotrematidae) from Silky Short-Tailed Bat,Carollia brevicaudaSchinz, 1821, in Peru

Anenterotrema is a genus of digeneans lacking digestive systems and parasitic in Neotropical bats. We have found a new species of Anenterotrema in silky short-tailed bats (Carollia brevicauda) from Peru. The new Anenterotrema species can be readily differentiated from previously described congeners by a combination of morphological characters. It differs from its morphologically closest cogener, Anenterotrema mesolecitha, in having smaller eggs, a much larger cirrus sac, and in the position of ovary. This is the sixth species of this genus and first to be described from Peru and C. brevicauda.

Stressful summers? Torpor expression differs between high- and low-latitude populations of bats

Variation in weather and food availability impacts the energy budgets of endotherms, with some species using torpor as an energy-saving strategy during periods of negative energy balance. We evaluated how latitudinal differences in energy balance relate to variation in torpor expression and roosting sociality between populations. We monitored summer skin temperatures (Tsk) of individuals from 2 populations of New Zealand lesser short-tailed bats (Mystacina tuberculata) separated by 6° of latitude using temperature telemetry. Although mean summer Ta was only < 1°C lower for the higher-latitude than lower-latitude population, individuals living at the higher-latitude site used torpor on 36% of observation days compared to 11% for lower-latitude bats. None of the recorded weather variables affected the propensity to enter torpor or torpor bout duration; however, the minimum torpid Tsk of bats positively correlated with daily minimum Ta. Roosts occupied by solitary bats were warmer than Ta, and temperatures within them fluctuated less than Ta. Higher-latitude individuals roosted solitarily (38%) more frequently than lower-latitude individuals (17%) and individuals from both populations exclusively used torpor while roosting solitarily. Arousals from torpor by higher-latitude bats coincided with sunset and not daily Ta maxima suggesting that bats were not fully exploiting advantages of passive rewarming. Site-specific roost choice and torpor patterns were apparent between M. tuberculata populations during summer, demonstrating that small differences in Ta differentially affect energetic strategy. The thermoregulatory behavior of species inhabiting latitudinal gradients in climate is highly plastic, likely to meet the specific challenges of their environment.

Distributional extensions of Carollia castanea and Micronycteris minuta from Guatemala, Central America

Abstract Field expeditions in 2011 that inventoried the terrestrial vertebrate fauna of two wildlife protected areas in the tropical Caribbean of Guatemala have produced the first confirmed records of two bats for the country: the white-bellied big-eared bat, Micronycteris (Schizonycteris) minuta (Gervais 1856) and the Chesnut short-tailed bat Carollia castanea H. Allen, 1890, both of neotropical distribution and with their current northern limit at Lancetilla, Honduras. The record of M. minuta at Sierra de Caral, Guatemala extends the range of this species 137 km to the west, and the record of C. castanea at Cerro San Gil extends its range 147 km to the west.

Opportunistic predation of a silky short-tailed bat (Carollia brevicauda) by a tawny-bellied screech-owl (Megascops watsonii), with a compilation of predation events upon bats entangled in mist-nets

Opportunistic predation of a silky short-tailed bat (Carollia brevicauda) by a tawny-bellied screech-owl (Megascops watsonii), with a compilation of predation events upon bats entangled in mist-nets

New record of bilateral hyperdontia in Carollia brevicauda (Chiroptera: Phyllostomidae)

Systematics and taxonomy of bats is based in part on the morphological characteristics of the teeth and dental formulas. However, sometimes dental abnormalities appear that involve changes in the shape and number of teeth which can lead to erroneous taxonomic identifications. Numerous cases of dental anomalies have been reported for all groups of mammals, especially bats, the group with the most dental anomalies reported. This note presents a rare case of bilateral hyperdontia in Carollia brevicauda , for which only cases of oligodontia had previously been registered. The dental anomaly was found in a male specimen of silky short-tailed bat from the middle basin Rio Guayuriba, Acacias, Meta, Colombia. The unusual individual shows an additional incisor annexed to each normal external incisor in the maxilla, with separate alveoli, for a total of 6 upper incisors, two more than normal. The extra teeth have a morphology similar to the external incisors characteristic of the species, short and rounded, and are located between the canine and the second (external) upper incisor on each side of the head. No other specimen among 66 individuals of the same species showed a dental anomaly. This is the first record of bilateral hyperdontia for C. brevicauda . This dental anomaly may be due to an isolated mutation in this individual, because no other specimens with this type of anomaly were found in the study area.

Survival of PIT-tagged lesser short-tailed bats (Mystacina tuberculata) through an aerial 1080 pest control operation

Survival of PIT-tagged lesser short-tailed bats (Mystacina tuberculata) through an aerial 1080 pest control operation