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Dietary proteins are considered crucial for growth and maintenance in mammals, but many fruit-eating mammals feed largely on a protein-poor diet. In the Chir-optera, frugivory has evolved twice, in the Old World Pteropodidae and in the New World Phyllostomidae, especially the Stenodermatinae. Recent studies based onthe analysis of nitrogen isotope ratios (d 15 N) suggest that phyllostomids feed to varying degrees on arthropods to meet their nitrogen (N) requirements. ArthropodfeedinghasrarelybeenobservedinPteropodidae.Thus,weaskedwhetherpteropodidsmeettheirNrequirementsbyfeedingexclusivelyonplantmatter.Wepredictedthattissuefrompteropodidwingmembranes shouldbe depletedin 15 Nrelativeto thoseofobligateinsectivorousrhinolophoid, vespertilionid oremballonurid bats,ifpteropodidsacquireproteinsexclusivelyfromfruits,leavesornectar.Wefoundthatd 15 Ninpteropodidsweresignificantlylowerthaninobligateinsectivorousbats.Inaddition, mean d 15 N of Old World pteropodids was similar to that of obligate frugivorous stenodermatines of the New World tropics. We infer from these data thatpteropodids are predominantly phytophagous bats. From a nutritional perspective, pteropodids and stenodermatines are very similar, suggesting that they shareconvergent physiological adaptations to compensate for the lack of dietary nitrogen.Key words: diet; insectivory; isotopes; nitrogen balance; Pteropodidae; Phyllostomidae.

Chestnut short-tailed bats, Carollia castanea, and Seba’s short-tailed bats, C. perspicillata (Phyllostomidae), were radio-tracked (N = 1593 positions) in lowland rain forest at Tiputini Biodiversity Station, Orellana Province, Ecuador. For 11 C. castanea, mean home range was 6.8 ± 2.2 ha, mean core-use area was 1.7 ± 0.8 ha, and mean long axis across home range was 438 ± 106 m. For three C. perspicillata, mean home range was 5.5 ± 1.7 ha, mean core-use area was 1.3 ± 0.6 ha, and mean long axis was 493 ± 172 m. Groups of less than fi veC. castanea occupied day-roosts in earthen cavities that undercut banks the Tiputini River. Carollia perspicillata used tree hollows and buildings as day-roosts. Interspecific and intraspecific overlap among short-tailed bats occurred in core-use areas associated with clumps of fruiting Piper hispidum (peppers) and Cecropia sciadophylla. Piper hispidum seeds were present in 80 percent of the fecal samples from C. castanea and 56 percent of samples from C. perspicillata. Carollia perspicillata handled pepper fruits significantly faster than C. castanea; however, C. castanea commenced foraging before C. perspicillata emerged from day-roosts. Evidence for exploitative competition between C. castanea and C. perspicillata is suggested by our observations that 95 percent of ripe P. hispidum fruits available at sunset disappear before sunrise (N = 74 marked fruits). Piper hispidum plants produced zero to 12 ripe infructescences per plant each night during peak production. Few ripe infructescences of P. hispidum were available during the dry season; however, ripe infructescences of C. sciadophylla, remained abundant.

Although the use of modified roosts has been reported in more than 20 species of bats in the tropics, comparative studies of the roosting ecology of congeneric tent-roosting species are notably lacking. In the Paleotropics, this unique behavior has been described in two species belonging to the genus, Cynopterus: C. sphinx and C. brachyotis. However, it is not known whether tent roosting is an essential component of their roosting ecology, or whether the behavior is found in other members of the genus. In this study we characterize the roosting ecology of four sympatric species of Cynopterus in peninsular Malaysia and use these data to address two main questions. (1) Do all four species use modified roosts and, in those that do, is tent-roosting obligate or opportunistic? (2) Do species pairs overlap in roost preferences and roosting habitat and, if so, is there evidence for interspecific interactions in relation to these resources? We radio-tracked bats at two floristically distinct sites and located a total of 249 roosts. Interspecific roost niche overlap was minimal at both sites and we found no evidence for interspecific competition for roost resources at the local level. Species differences in roosting ecology were defined primarily by spatial separation of roosting habitats and secondarily by within-habitat differences in roost selection. Importantly, we found that although periodic use of modified roosts was a characteristic shared by all four species, most roosts were unmodified, indicating that tent roosting is a facultative behavior in Malaysian Cynopterus.

The aims of this study were to investigate the diet and relative abundance of fruit bats in a lowland Malaysian rain forest and to test the hypothesis that the local assemblage structure of fruit bats varies significantly over time in relation to the availability of food. In total, 352 fruit bats of eight species were captured during 72,306 m2 mist-net hours of sampling between February 1996 and September 1999. Three species of fruit bats (Balionycteris maculata, Chironax melanocephalus, and Cynopterus brachyotis) that fed on a wide range of “steady state” and “big bang” food resources were captured continuously throughout the study period, with no significant variation in capture rates over time. In contrast, five species that fed exclusively or almost exclusively on “big bang” food resources were sampled intermittently, with significant temporal variation in the capture rates of two species (Cynopterus horsfieldi and Megaerops ecaudatus). Significant variation in the capture rates of the remain...

The aims of this study were to (1) characterize the food resources exploited by fruit bats (Pteropodidae) within an old-growth Malaysian dipterocarp forest, (2) test the viability of the seeds they disperse, and (3) provide an estimate of the proportion of trees that are to some degree dependent upon bats for seed dispersal and/or pollination. Fruit species exploited by bats could be distinguished from those eaten by birds largely on the basis of color (as perceived by human beings). Bat-dispersed fruits were typically inconspicuous shades of green–yellow or dull red–brown, whereas fruits eaten by birds were generally bright orange to red. Dietary overlap between bats and nonflying mammals was relatively high. In contrast to primates and squirrels, which were major seed predators for several of the plant species under investigation, fruit bats had no negative impact on seed viability. A botanical survey in 1 ha of old-growth forest revealed that 13.7 percent of trees (≥15 cm girth at breast heigh...

We review reports of leaf-eating by bats and present new evidence for folivory by leaf fractionation for the neotropical bat Artibeus jamaicensis (Chiroptera: Phyllostomidae). Leaf-eating has been reported for at least 17 species of OldWorld Megachiroptera and four species of New World Microchiroptera. Leaves eaten by bats indude at least 44 species of plants represented by 23 different families. Plant families which account for the greatest species richness (numbers of species given in parentheses) indude the Leguminosae (12), Moraceae (4), and Solanaceae (4). Evidence for folivory by A. jamaicensis is based on captures of bats carrying leaves, and collections of whole and partially chewed leaves and discarded pellets recovered from beneath feeding roosts. Whole leaves carried into caves by A. jamaicensis and partially chewed, but discarded leaves included Erythrina poeppigiana, Ficus sp., and Calophyllum calaba, in decreasing order of frequency. Bats captured while carrying Erythrina leaves were most often mature males. Erythrina poeppigiana leaves are relatively high in protein (> 19% dry-matter content) and low in fat (1%). Our observations that A. jamaicensis selects and chews leaves high in protein and rejects protein-poor, fibrous pellets, support the hypothesis that these bats extract liquid fractions which contain a reliable source of dietary protein. Although we have no direct evidence that male or female A. jamaicensis transport leaves to feeding roosts located outside of caves, we suggest that liquid fractions derived from leaves may provide females with an important source of protein, especially during periods of pregnancy and lactation. Folivory, once thought to be rare among plantvisiting bats, may in fact be quite common and widespread, especially among species that feed largely on fruits which are low in protein.

The social organization of Artibeus jamaicensis was examined in Aguas Buenas Cave, Puerto Rico, by sampling roosting clusters of bats during the spring reproductive period. Most clusters consisted of 2-14 pregnant or lactating females (and their young) and a single adult male. This suggests a harem type of social organization. Two types of non-harem groups represented by nonreproductive females or sexually mature males supports this conclusion. Although our observations do not permit distinction between alternative explanations for harem formation, they do indicate that successful harem aquisition and maintenance is age or size related. Older and heavier males had larger harems than younger or smaller harem males. The occurrence of harem groups in tree hollows (Morrison 1979) and in caves (this study) suggests that environmental factors promoting harem social organization in A. jaamaicensis can vary between populations. BATS EXHIBIT A DIVERSITY OF social and mating systems (Bradbury 1977a), including promiscuity (e.g., Myotis lucifugus, Thomas et al. 1979), monogamy (e.g., V1ampyrum spectrum, Vehrencamp et al. 1977), female-defense polygyny (e.g., Phyllostomas hastatus, McCracken and Bradbury 1977, 1981), resource-defense polygyny (e.g., Artibeus jamaicensis, Morrison 1979; Morrison and Morrison 1981), and leks (e.g., Hypsignathus monstrosus, Bradbury 1977b). Certain components of bat social organization such as group size, age structure, sex ratio, and population density can vary considerably among populations (Bradbury 1977a, Bradbury and Vehrencamp 1976), particularly where there is variation in habitat conditions. Knowledge of intraspeciflc variation in social organization is necessary to fully understand how environmental and demographic factors influence the evolution of social systems (Eisenberg 1981). The phyllostomid bat Artibeus jamaicensis is well suited for evaluating variation in social and mating organization. This species has a widespread distribution, including several insular forms (e.g., Baker and Genoways 1978), and it is one of the most abundant bats occurring in the Neotropics. Roosting sites include tree hollows (Morrison 1979, Morrison and Morrison 1981), foliage (Goodwin and Greenhall 1961; Jimbo and Schwassman 1967; Foster and Timm 1976; Morrison 1978a, 1979), and caves (Dalquest 1953, Tuttle 1968, Goodwin 1970, Thomas 1974, Lemke 1978). With the exception of Morrison's (1979) study, little is known of group composition for roosting A. jamaicensis in these situations. Morrison described a resource-defense polygyny system for this species on Barro Colorado Island, Panama, and in Chamela, Mexico. Males maintained harems by defending tree hollows used by groups of females as day roosts. He suggested that this type of mating system was feasible only in habitats where a limited number of tree hollows were available as day roosts, and that the cost to males of defending "less confined" roosts such as caves and foliage might be prohibitive. The purpose of this study was to determine the social structure of A. jamaicensis roosting in a cave environment. MATERIALS AND METHODS We sampled the composition and distribution of day roosting clusters of A. jamaicensis during the spring reproductive period in Aguas Buenas Cave, Puerto Rico (6606'30"W, 18014'01"N) from 5 May to 16 May 1981. We limited our survey of bats to the upper, drier portion of the cave system. Details of the geology, ecology, and mycology of this cave are given elsewhere (Peck 1974; Beck et al. 1976; Carvajal-Zamora 1977a, b, c). Clusters of A. jamaicensis were found in solution cavities on the ceiling usually well away from entrances (Fig. 1). Those cavities occupied by A. jamaiciensis were generally 4-15 m above the cave floor and were usually dome-like in shape, approximately 0.5-1 m in diameter by 1-2 m deep. If no loud disturbances were made, roosting bats allowed us to walk directly beneath them. Clusters of Artibeus were captured using a device similar to that described by McCracken and Bradbury (1981). This consisted of a cylindrical, plastic trash bucket (32 X 36 cm) with the bottom removed. A 45 cm deep hardware cloth basket (2.5 mm mesh), with a 4 cm hole in the bottom, was attached beneath the plastic bucket. The entire device was attached with the open end of the bucket at the tip of a 3.5 m pole. Clusters of A. jamaicensis were collected by quickly placing the open end of the ' Present address: Department of Zoology, University of Rhode Island, Kingston, Rhode Island 02881, U.S.A. 2 Present address: Illinois Natural History Survey, 607 E. Peabody Drive, Champaign, Illinois 61820, U.S.A. BIOTROPICA 15(2): 133-138 1983 133 This content downloaded from 157.55.39.45 on Fri, 02 Sep 2016 05:41:32 UTC All use subject to http://about.jstor.org/terms bucket into occupied solution cavities, thus obstructing the bats' route of exit. A second pole inserted through the hole at the bottom of the container was carefully maneuvered so that bats dinging to the sides of the cavity were dislodged. For each captured individual, we recorded sex, age class, reproductive condition, body mass, forearm length, canine tooth wear class, and for males, testes length and canine length. We recognized three age classes: juveniles (bats attached to a lactating female or with unfused phalangeal epiphyses), subadults (bats with fused epiphyses but without adult pelage), and adults (bats with fused epiphyses and adult pelage). Reproductive conditions recorded were extraor intra-abdominal testes for males and lactating, pregnant, or non-breeding for females. All linear measurements were taken with dial calipers, and body mass was measured with a Pesola spring scale. Tooth wear classes were adopted from Twente (1955). Briefly, completely worn canines were given a score of six and sharply pointed, unworn canines were scored as one. Bats from each cluster were marked with a unique set of colored plastic wing bands. Males were banded on the right forearm and females on the left. All bats were released immediately after being examined, usually no more than two hours after capture. The location of solution cavities in which dusters were captured was marked with a small flag on the cave floor. The presence or absence of bats in each of the censused solution cavities was noted on subsequent visits to the cave. To estimate the abundance of potential roost sites, two of us independently walked through the cave where A. jamaicensis was known to roost. Both of us recorded the number of occupied solution cavities as well as the number of unoccupied cavities showing signs of use. Solution cavities used by roosting bats had conspicuous, dark excrement stains on the sides of the dome interior. We characterized air temperature in occupied and unoccupied solution cavities by placing a thermistor probe attached to the end of a long wooden pole near the domes of cavities. The thermistor was interfaced with a Yellow Springs, Model 44, Telethermometer, which provided immediate temperature readings. Air temperature also was recorded at various heights and locations throughout the cave. FIGURE 1. Small harem group of Artibeus jamaicensis occupying a solution cavity in Aguas Buenas Cave, Puerto Rico. 134 Kunz, August, and Burnett This content downloaded from 157.55.39.45 on Fri, 02 Sep 2016 05:41:32 UTC All use subject to http://about.jstor.org/terms