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Almost all bat species worldwide are, despite pronounced differences in ecology and life history, social. This makes them ideal organisms for studying the diversity and evolution of sociality. However, almost all work has focused on maternity colonies and most studies have been done on temperate species. Although simple density-dependent factors such as thermoregulatory benefits to the offspring or limited availability of roost sites have been refuted as the main driving forces behind sociality, it remains often impossible to disentangle factors associated with breeding from other potential actors on social organization. The study of multimale associations, a hitherto neglected social organization in bats, could provide a solution to this dilemma. Using data from male colonies of particolored bats (Vespertilio murinus, Linnaeus, 1758) in Switzerland I explain how sociality for male particolored bats is likely to be the best of a bad job and that competition over future matings determines when individuals leave the colony. Although multimale associations could potentially yield important insight into the mechanisms shaping social organization, we currently lack information about many aspects of such associations, which we need in order to understand social organization in its full detail.
Within the broad continuum of polygyny, the mating systems of harem-forming bats exhibit a high degree of interspecific diversity and intraspecific variation. Here, I review the social structure and mating systems of 4 nominal species in the Old World fruit bat genus Cynopterus, and explore the relationship between roosting ecology, the size and stability of female groups, and variation in degree of polygyny. Intraspecific comparisons for C. brachyotis Sunda and C. sphinx suggest that the distribution and availability of suitable roost sites has a strong influence on the dispersion of females among males. Examination of paternity data for C. sphinx demonstrates a direct relationship between the environmental potential for polygyny and variance in male reproductive success: a 2-fold increase in mean harem size due to reduction in roost availability produces a 2-fold increase in reproductive skew among males. However, in C. brachyotis Sunda, C. sphinx, and C. horsfieldii, low fidelity of females to roosts or males is consistent, regardless of roost dispersion or permanence. In contrast, female C. brachyotis Forest exhibit high short-term fidelity to males, despite low roost fidelity. It is proposed that female lability is influenced by the distribution of potential mates and the benefits of multiple mating and, in C. brachyotis Sunda and C. sphinx, is likely to promote both behavioral and cryptic female choice, and male sperm competition.
Vertebrate mating systems are influenced by ecological and phylogenetic factors, and the variation observed in mating behavior is frequently attributable to the extent to which male assistance in the rearing of offspring increases a female's reproductive rate, size and stability of female groups, and density and distribution of females in space. In this study we evaluate patterns of association and parentage to describe the mating system of the tent-making bat Artibeus watsoni. During 16 consecutive months, we regularly surveyed 2 sites in southwestern Costa Rica and determined size, composition, and stability of social groups, and established patterns of parentage within roosts. We found female-biased, mixed-sex social groups formed by individuals located in several roosts within an area. Roosting associations were low (average across all sites: 31%), and the frequent changes between roosting partners suggests that males and females formed nonexclusive mating bonds, which was further supported by our finding that only 27% of young were sired by the male within a roosting group. Paternal sibships were only observed in 17% of dyads of young roosting together, indicating that few males copulated with >1 female of the roosting group during the mating season. However, paternal sibships were only observed in Golfito, which could be explained by greater group size and stability attributable to lower roost availability. Thus, our findings are consistent with a polygynandrous mating system (2 or several males sharing access to 2 or several females, and vice versa) in which males associated intermittently with females that frequently switched roosts, and where breeding opportunities for males seemed related to the defense of roosts, roosting territories, or both.
Strategies of males in harem-forming mammals may change depending on 2 variables, female group size and consequent ability of the harem male to monopolize copulations, and the relative costs and benefits of tolerating other males. We studied harems of 4–20 females associated with a dominant male in small groups of Artibeus jamaicensis (<14 females), and with dominant and subordinate males in large groups (>14 females). Dominant males displayed defensive behavior toward satellite males when they intruded into the roosting site. Small groups received the highest number of visits by satellite males, and dominant males did not display total defense of females. During the breeding season, females roosted in highly compacted clusters and dominant males were more active in their defensive behavior. Subordinate males were generally tolerated in harem groups and their presence reduced the number of adult male visits. Some young in large harem groups were sired by subordinate males, resulting in a genetic benefit for both dominant and subordinate males. Dominant males had the highest fitness in the large harem groups by sharing paternity with related subordinate males and by rejecting unrelated intruders.
Shelters are important for the survival and reproduction of many animals and this is particularly true for bats. Depending on the future use and effect of shelters on the fitness of individuals, not all members of a group of animals may contribute equally to shelter making. Thus, knowledge about the identity of shelter-making individuals may teach us much about the social system and mating strategy of species. To exemplify this, we review what is known about the roost-making behavior and the social system of Lophostoma silvicolum, a neotropical bat that excavates roost cavities in active arboreal termite nests. Roosts in termite nests are highly beneficial for the bats because they offer improved microclimate and possibly are responsible for the lower parasite loads of L. silvicolum in comparison to bat species using other, more common, roost types. Examination of observational field data in combination with genetic analyses shows that roost cavities excavated by single males subsequently serve as maternity roosts for females and that this improves reproductive success of the male who excavated the roost. This suggests that roosts in termite nests serve as an extended male phenotype and roost making is a sexually selected behavior. Roost-making behavior is tightly linked to the species' social organization (single-male–multifemale associations that stay together year-round) and mating system (resource-defense polygyny). The case study of L. silvicolum shows that it is important to learn more about the implications of shelter making in bats and other animals from ongoing and future studies. However, differences in costs and benefits for each group member must be carefully evaluated before drawing conclusions about social systems and mating strategies in order to contribute to our current knowledge about the evolution of sociality in mammals.
Polygyny and promiscuity are the 2 most common mammalian mating systems, whereas monogamy and lek mating are rare. Mammalian mating systems are thought to be influenced by the amount of paternal investment required, defensibility of females, and the stability and size of female groups. With some notable exceptions, male bats typically make no paternal investment and, because of high mobility and broad foraging areas of females, ranges of females often are not defensible. Thus, we would expect most bats to be polygynous or promiscuous; however, mating systems of only about 6% of bat species have been studied. Mating systems of leaf-nosed bats in the family Phyllostomidae have not been well studied, and no species in subfamilies Glossophaginae and Phyllonycterinae, a major radiation of nectar-feeding phyllostomids, have been studied. The buffy flower bat (Erophylla sezekorni) is a phyllonycterine bat endemic to islands of the Greater Antilles. We describe the social structure and mating system of E. sezekorni on Exuma, Bahamas, using capture data, roost observations, and paternity analysis. E. sezekorni roosts in multimale–multifemale groups and female groups are large (50–350 bats) and labile. Males of E. sezekorni aggregate at display areas where they exhibit wing displays and hold territories throughout the 2-month mating season. Mature males also produce garlic-scented supraorbital secretions and ultrasonic display calls. Paternity analysis revealed that females do not mate exclusively with displaying males and that there is limited polygyny and reproductive skew. We also found sexual dimorphism in body mass and condition, with males being both heavier and in better condition than females. Based on large female group size, female group lability, and existence of male mating territories, we hypothesize that E. sezekorni employs a form of promiscuous mating system. More data about female mating behavior are required to test this hypothesis.
Like many other mammals, Saccopteryx bilineata exhibits a polygynous mating system, in which each male defends a group of females called a harem. Colonies consist of several harems, and nonharem males roost adjacent to harems. Unlike most other mammals, females disperse from their natal colony and most juvenile males remain in it. Thus, colonies consist of patrilines, which promotes intense local mate competition. Females are in estrus during a few weeks at the end of the rainy season. Mating is most likely initiated by females and preceded by intense courtship displays of males. Forty percent of colony males do not sire any offspring during their tenure in the colony, whereas a few males can sire up to 6 offspring in a single year. Males use olfactory, visual, and acoustic signals for courtship, and they demonstrate territory ownership by scent marks, low-frequency calls, and visual displays. Harem males sire on average more offspring than do nonharem males but produce only 30% of the offspring within their own harem territory, with 70% being sired by other harem males or nonharem males. Reproductive success of males increases with decreasing size, fluctuating asymmetry, and fundamental frequency of territorial calls. In addition, females that are closely related to the harem holder are more likely to mate with other males than with the harem holder. Sexual selection in S. bilineata is most likely influenced by intense local mate competition caused by scarce roosts and the patrilineal organization of colonies.
The prevailing view of the social organization of temperate bats is that maternity colonies represent aggregations of philopatric females connected to other maternity colonies via male-mediated gene flow. However, few studies have examined fine-scale patterns of matrilineal diversity within and between colonies, and clear evidence of strict philopatry generally is lacking. Here we examine patterns of genetic diversity within and among maternity colonies of big brown bats (Eptesicus fuscus) using both microsatellites and mitochondrial sequences. As in other temperate bats, we observed no differentiation among colonies using nuclear microsatellite markers (FST: −0.0001–0.012; 99.5% of variation within populations). Overall, there was significant mitochondrial structure among colonies, but the pattern was complex, with low ΦST values among some populations and high values among others (range: −0.007–0.491). Three groups of colonies were identified in nested analyses of molecular variance, among which variation was high (21.2% of the variation), but within which variation was low (1.4%), and significant matrilineal isolation by distance (r = 0.56, P = 0.012) was observed. Maternity colonies were characterized by high haplotype diversity (hX̄ = 0.83) and a large number of matrilines (5–15) per colony. Furthermore, we observed a small number of maternities within colonies, and only 5–17% (X̄ = 9%) of the sampled females were found roosting with a mother or daughter. Our results are inconsistent with strict female philopatry, and suggest that female-mediated gene flow may occur among some maternity colonies. The potential for female dispersal in temperate bats prompts new and exciting questions about social and dispersal dynamics.
Taxonomists have debated whether the complex of long-tailed shrews adapted to talus slope formations in the Appalachian Mountain range in eastern North America should be considered 1 species (Sorex dispar) or 2 species (S. dispar and S. gaspensis). Recent analyses of mitochondrial DNA and morphological data have suggested that these 2 taxa should be considered conspecifics. To help resolve this debate, a combination of mitochondrial (cytochrome-b [Cytb] sequence data) and nuclear markers (inter–SINE fingerprinting [where SINE is short interspersed element]) markers was analyzed from specimens collected from across the range of this complex, including the zone of contact between these putative species. Here we present our analyses of Cytb sequences and inter-SINE fingerprinting data that supports recognizing a single species composed of a monophyletic group of genetically highly similar shrews. Both data sets support the hypothesis of a single, relatively rapid expansion following the retreat of the Laurentide ice sheet, and the possibility of a northern refugium. We recommend recognizing these 2 taxa as conspecific, with S. dispar having nomenclatural priority.
The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S. fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and suggest that rapid chromosomal reorganization occurred in the karyotype evolution of this species, possibly due to founder or bottleneck events.
Based on examination of molecular data and pelage patterns, it has recently been suggested that the island populations of the clouded leopard, traditionally considered a subspecies, may, in fact constitute a separate species. In this paper, I demonstrate that the island populations deviate strongly from the mainland populations in a large number of cranial, mandibular, and dental characters. The differences far exceed those that have been documented for subspecies within other pantherine felids, and are congruent with a separate species, to which the name Sundaland clouded leopard, Neofelis diardi, has been given, although the name Diard's cat has priority based on historical precedence. I suggest that the vernacular name Diard's clouded leopard be adopted for Neofelis diardi. In contrast, mainland populations diverge less from each other, and are congruent with 1 species (Neofelis nebulosa) and 2 subspecies, the western (N. n. macrosceloides) and eastern (N. n. nebulosa) clouded leopard. Neofelis deviates from other large felids in many aspects of craniodental morphology, and most likely also in several behavioral aspects. Diard's clouded leopard appears more derived with respects to saber-toothed craniodental features than the clouded leopard, indicating that the former may have gone farther than the latter in convergently evolving craniomandibular features traditionally considered characteristic of primitive saber-toothed felids.
By comparison with murine rodents such as rats, the middle ear structures of many subterranean mammals appear to be enlarged and thus adapted toward low-frequency sound transmission. However, comparison with closely related terrestrial outgroups has not always been undertaken, and apparent specializations in some cases might reflect phylogeny rather than habitat. Examination of the middle ear of the nonsubterranean degu (Octodon degus) under light microscopy revealed a septated middle ear cavity, a circular tympanic membrane lacking a pars flaccida, a malleus with elongated head, synostosed with the incus, a typically bicrurate stapes, and no stapedius muscle. Many of these features are shared with closely related, subterranean octodontoids in the genera Ctenomys (tuco-tucos) and Spalacopus (coruro). Caviomorph rodents in general share a very similar middle ear morphology, regardless of habitat, which suggests that sensitive low-frequency hearing is plesiomorphic for this group, rather than being specifically associated with a subterranean lifestyle.
Tree shrews are small mammals living in the tropical forest of Southeast Asia. The habitus of species within the genus Tupaia is often quite similar, so that it is difficult to differentiate the species based on their morphology. We applied comparative bioacoustics, a tool successfully used to discriminate cryptic species of nocturnal mammals, to investigate whether species in the diurnal genus Tupaia can be recognized noninvasively on the basis of a conspicuous loud call, the chatter. We studied to what extent the chatter call of 2 tree shrew species, Tupaia glis and T. belangeri, differed in acoustic structure. We also acoustically analyzed the chatter call of T. chinensis, a subspecies or closely related parapatric species of T. belangeri. Analyzed acoustic features allowed assigning chatter calls with a probability of more than 73% to the species that produced them. Bioacoustical differences are in line with subtle morphological differences, supporting species status for all 3 studied tree shrew species and corroborating immunodiffusion and genetic data that differentiate T. glis and T. belangeri. Loud calls may offer a reliable noninvasive tool for species diagnosis and discrimination in cryptic species of this diurnal mammalian group.
We analyzed social patterns indicative of the mating system and parental care in a population of the southern bamboo rat (Kannabateomys amblyonyx). This arboreal rodent feeds exclusively on bamboo stems and leaves. We conducted fieldwork from August 2003 to October 2004 in southern Brazil (30°20′–30°27′S, 50°50′–51°05′W), in patches of introduced Chinese bamboo (Bambusa tuldoides). We captured 18 individuals, 7 of which were adults that received radiotransmitters and were followed from 1 to 12 months. Another 5 animals (adults or subadults) received colored collars. We observed paternal care, delayed juvenile dispersal, and reduced degree of sexual dimorphism, all of which are traits typical of social monogamy. Mated males showed a direct parental behavioral repertoire similar to that of females (with the obvious exception of nursing), including grooming, huddling, and food provisioning. Potential monogamy in this species seems to be a flexible strategy linked to low density of bamboo patches. Females were confined to widely spaced, small home ranges, decreasing the possibility of male defense of and access to >1 female. The arboreal habits of the species possibly increase the risk of inexperienced young falling from trees or else being depredated when moving exposed through branches. This risk is probably reduced by the extensive biparental care observed, including the providing of low-energy plant food to young in the nest.
Many mammalian species exhibit intersexual differences in sociospatial behavior; however, sociality of adult males in species with solitary females is relatively rare. Male raccoons (Procyon lotor) in southern Texas form social groups that have many similarities to male coalitions in other species, including spatially distinct home-range boundaries that are maintained year-round. Within these groups, males rest and travel together with varying frequencies. However, the length of social bonds and genetic relationships among group males are unknown. We quantify characteristics of male social groups for raccoons in southern Texas, examine the genetic structure of the population, and finally test whether variation in relatedness within groups is related to the frequency or length of association between males. Mean proportions of locations within 50 or 100 m for each dyad ranged from 0.04 to 0.48 for the duration of group membership, although most dyads had means between 0.20 and 0.30. Duration of dyads ranged from 6 to 39 months, with a mean of 18.4 months. Mean band-sharing coefficient for males within groups was not different (1-tailed P = 0.376) from males between groups. However, mean coefficient for males within groups was lower (P < 0.01) than that for litters, suggesting that male groups were not exclusively composed of close relatives. Genetic relatedness explained little of the variation of proportions of locations within 50 or 100 m within groups (1-tailed P = 0.26); however, band-sharing coefficients were positively related (1-tailed P = 0.06) to duration of associations within groups. Kin selection does not appear to explain male sociality in raccoons, but relatedness may be related to the length of associations between males within groups.
Male-biased sexual size dimorphism is typical of polygynous mammals, where the degree of dimorphism in body mass is related to male intrasexual competition and the degree of polygyny. However, the importance of body mass in monogamous mammals is largely unknown. We investigated the effect of body mass on life-history parameters and territory size in the red fox (Vulpes vulpes), a socially monogamous canid with slight sexual dimorphism. Increased body size in males appeared to confer an advantage in territory acquisition and defense contests because heavier males held larger territories and exerted a greater boundary pressure on smaller neighbors. Heavier male foxes invested more effort in searching for extrapair matings by moving over a wider area and farther from their territories, leading to greater reproductive success. Males that sired cubs outside their own social group appeared to be heavier than males that only sired cubs within their social group or that were cuckolded, but our results should be treated with caution because sample sizes were small. Territory size, boundary pressure, and paternity success were not related to age of males. In comparison, body mass of females was not related to territory size, probability of breeding, litter size, or cub mass. Only age affected probability of breeding in females: younger females reproduced significantly less than did older females, although we did not measure individual nutritional status. Thus, body mass had a significant effect on life-history traits and territory size in a socially monogamous species comparable to that reported in polygynous males, even in the absence of large size dimorphism.
Although the brown bear (Ursus arctos) is generally classified as an endangered species, the size and range of several bear populations are increasing in different parts of the world. Understanding how this occurs is essential for the species' management. Using reliable signs of bear presence and models, we analyzed multiple aspects of the spatial expansion of the brown bear population in Slovenia from the Core Bear Protective Area (an area established in 1966 for the conservation of brown bears; hereafter, Core Area) toward the Alps and other parts of the country in 1945–1995. Bear population densities increased between 1945 and 1995, but densities decreased with distance from the Core Area. The observed proportion of females increased overall during the study period from 6% to 20%, but decreased with distance from the Core Area from 27% (0–10 km from the Core Area) to 5% (>70 km from the Core Area). This pattern likely is a consequence of male-biased dispersal, which can cause substantial changes in the sex structure of peripheral parts of populations in space and time. The population showed a net annual growth rate of 1.7%, and expanded spatially at an average rate of 1.6–1.9 km/year. Some females were recorded far from the Core Area (>80 km), suggesting that unlike in stable or declining populations, females in expanding populations can exhibit long-distance dispersal. However, the frequency of females that dispersed far was so small that it probably had little impact on the dynamics of the population expansion.
The Apennine brown bear (Ursus arctos marsicanus) is an endangered subspecies endemic to Italy, where a small population, estimated at 40–50 bears, inhabits a human-dominated landscape. Although little is known of the ecology of this population, habitat loss and fragmentation often has been considered one of the main threats for small and endangered populations. To assess habitat availability at the landscape scale, we used a distribution model to compare historical, present, and future land-cover suitability for the Apennine brown bear population in central Italy. The 4 models are based on 3 existing land-cover maps (1960, 1990, and 2000) and 1 simulated map for 2020, obtained from a cellular-automata Markov-chain land-transition model. We also compared changes in human population density as a surrogate for human pressures on bear habitat, and we measured the contribution of protected areas to the bear's conservation. Our results show that, at the landscape level and assuming that current human population trends continue in the future, land-cover suitability does not seem to be an issue or priority. The current negative trend of this population, despite opposite trends in land-cover suitability, suggests that conservation efforts should focus more on direct actions aimed at reducing human-caused mortality and enhancing population expansion into suitable unoccupied areas.
Denning and resting site use by radiocollared eastern spotted skunks (Spilogale putorius) in the Ouachita Mountains of western Arkansas was investigated from May through August 2005 and 2006. We identified and characterized microhabitat and landscape characteristics of 127 resting and den sites. Sites were located in burrows excavated by other mammal species (48%), in decayed or burned root systems (22%), in rocky outcrops (14%), in eastern woodrat (Neotoma floridana) nests (9%), or in ground-level tree or log cavities (7%). Reuse of sites by the same individual was common (32.3%), but use of the same site by different individuals was rare, as was communal use of sites (<1.0% each). Contrasting used and putatively available dens and resting sites, we found that sites were selected based primarily on increased vegetative cover, which supports hypotheses that thermal regulation and predator avoidance may underlie den and resting site selection. Higher rock and vine densities, younger pine forest stands, older hardwood stands, steeper slope, and smaller site entrance also positively influenced resting and den site selection. These findings suggest that eastern spotted skunks select structurally complex sites, likely to enhance protection from predators. Eastern spotted skunks may thus be vulnerable to habitat alterations that reduce this structural complexity.
California sea lions (Zalophus californianus) occur along much of the Pacific coast of North America, but the number of breeding areas that are occupied is relatively small. Our understanding of the attributes that make these few sites preferable is currently limited. We quantified habitat characteristics—substrate type and coloration, aspect, slope, curvature of shoreline, and availability of shade, water pools, and resting areas—at 26 sites (7 islands) occupied by sea lions and 33 unused sites (8 islands) distributed throughout the Gulf of California, Mexico. Logistic regression models were used to explore how habitat characteristics explained sea lion occupancy patterns. Models discriminated very well between occupied and unused sites, and showed that occupied locations were more often located in sites with larger-size rocks (odds ratio [OR] = 1.209), lighter-color substrates (OR = 0.219), and convex shorelines (OR = 1.067). All of these preferred characteristics are likely to play a role in the prevention of heat stress in sea lions, suggesting that increases in temperature, such as those expected from global warming, may pose an additional risk for this already declining sea lion population. To partially offset this risk, our results may be used to identify, and protect, unused but suitable (i.e., thermally favorable) habitat. In addition, we recommend effective protection and monitoring of the currently occupied areas and their populations.
Much of our present knowledge of mixed migration strategies of northern populations of white-tailed deer (Odocoileus virginianus) comes from short-term studies, which limits the observed variation of winter severity and thus our understanding of its potential influence on the migration behavior of study cohorts. From 1991 to 2006, we assessed the incidence of autumn migratory versus nonmigratory behavior of 335 adult (>1.0 year old) females, what proportion were conditional versus obligate migrators, the importance of winter severity as a factor affecting the migratory response, and the effect of winter severity and study length on the classification of deer as conditional or obligate migrators and composition of study populations. Annual winter conditions ranged from historically mild to severe. The annual estimated proportion of deer migrating from spring–summer–autumn range to winter range was positively related to winter severity, and the cumulative probability of deer migrating tracked accumulating snow depths as winters progressed. However, the relationship was highly variable, largely attributable to the annual variation in migratory behavior of individuals radiomonitored for 2–7 years. Importantly, because of the variability of autumn–winter weather conditions, we noted that the proportion of deer we classified as obligate migrators was inversely related to the number of years individuals were monitored. Further, the composition (nonmigratory, conditional, and obligate migrators) of the study cohort was strongly influenced by the severity of winter conditions in the year of capture, as well as in subsequent winters of monitoring.
Mammals can have either generalized (mixed) or specialized diets. We expected swamp wallabies (Wallabia bicolor) to have mixed diets, and predicted a negative relationship between the selection of a food type and its relative availability (negative frequency dependence). We collected data on diets in a native Eucalyptus forest where the relative availability of food types (defined as 5 plant functional groups: ferns, forbs, monocots, shrubs, and trees) had been altered by timber harvesting. A comparison of diets between individuals living in 2 habitat types (unharvested forest and 5-year-old regenerating areas) showed that in both habitats forbs were the major dietary component, although moderate amounts of shrubs and monocots also were consumed. Trees and ferns were eaten less at unharvested sites, and more at 5-year-old sites. Nonmetric multidimensional scaling followed by a multiresponse permutation procedure demonstrated a substantial difference in diet composition between the habitats (multiresponse permutation procedure: A = 0.20, P < 0.001), but when analyzed using an index of diet selection, the difference was smaller (A = 0.05, P = 0.04). Three alternative analyses demonstrated negative frequency dependence in many cases, a result generally consistent with a mixed feeding strategy. With the exception of tree foliage, selection was positively correlated with the relative availability of at least 1 other food type, and largely uncorrelated with 3 forage quality variables (nitrogen, water, and dry matter digestibility). Additional data at a finer resolution and in different seasons are required to test the generality of these conclusions.
We examined the feeding habits of the Indian giant flying squirrel (Petaurista philippensis) in a rain-forest fragment in southern Western Ghats, India, from December 1999 to March 2000. Flying squirrels consumed 4 major plant parts belonging to 9 plant species. Ficus racemosa was the most-eaten species (68.1%) during the period of the study, followed by Cullenia exarillata (9.57%) and Artocarpus heterophyllus (6.38%). The most commonly consumed food item was the fruit of F. racemosa (48.93%). Leaves formed an important component of the diet (32.97%) and the leaves of F. racemosa were consumed more than those of any other species. Flying squirrels proved to be tolerant of disturbance and exploited food resources at the fragment edge, including exotic planted species.
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