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Peter D Weigl - One of the best experts on this subject based on the ideXlab platform.
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Persistence of southern flying squirrel winter aggregations: roles of kinship, familiarity, and intruder squirrels
Journal of Mammalogy, 2011Co-Authors: Katherine K Thorington, Peter D WeiglAbstract:Abstract Southern flying squirrels (Glaucomys volans) are seasonally gregarious and rely on the thermoregulatory benefits of well-constructed nests and presence of nest mates to survive harsh winter conditions. Prior work has shown that kinship components are important to how winter aggregations form in captivity and that relatedness between individuals is higher than expected in undisturbed populations examined in the field. Over the course of 2 falls, 2006 and 2007, we created related and unrelated groups in a laboratory colony at Wake Forest University. We presented each group type with related and unrelated individuals as intruders. Once formed, aggregations persisted when presented with an intruder squirrel. Squirrels from existing aggregations were found in the same nest box 98% of the time. Factors of relatedness and familiarity were crucial in determining whether the intruder was accepted into an existing aggregation or nested alone. We found that related groups were more tolerant of truly novel (...
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Role of kinship in the formation of southern flying squirrel winter aggregations
Journal of Mammalogy, 2011Co-Authors: Katherine K Thorington, Peter D WeiglAbstract:In winter southern flying squirrels (Glaucomys volans) aggregate in large groups. They live on food items individually stored during the fall in their overlapping home ranges. The squirrels gain thermoregulatory benefits from living in aggregations but also face costs of group living, especially nest mates pilfering individually stored food. Other costs include increased predator attraction and a greater vulnerability to parasite infection. The presence of relatives in the group has the potential to increase inclusive fitness by increasing the availability of food, stored in the home area, to related individuals. Using 3 generations of known-relationship squirrels we conducted laboratory experiments to determine whether kin or familiar animals were preferred nest mates during aggregation formation. During 3 time periods, over 2 winters, squirrels were presented with kin and nonkin and familiar and unfamiliar animals and allowed to aggregate over the course of multiple 3-day trials. Kinship was persistently a major factor in the formation of aggregations. Squirrels aggregated with highly related animals (parents, offspring, and siblings) significantly more often than with unrelated animals. Familiarity became significant by the end of the study. Understanding how relatedness and familiarity interact in the formation of aggregations in seasonally gregarious animals sheds light on the processes and factors that lead to sociality.
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genetic relatedness in winter populations of seasonally gregarious southern flying squirrels Glaucomys volans
Journal of Mammalogy, 2010Co-Authors: Katherine K Thorington, Jackie D Metheny, Matina C Kalcounisrueppell, Peter D WeiglAbstract:Southern flying squirrels (Glaucomys volans) face a dilemma: winter aggregation is beneficial for thermoregulation but costly due to nest mates pilfering stored food in the home area and the tendency for groups to attract predators. Living with kin in winter aggregations may mitigate these deleterious effects because if an individual dies, its stored food can be beneficial to relatives, thereby increasing inclusive fitness. Southern flying squirrels from 7 populations and a captive colony were genotyped at 6 microsatellite loci. We calculated group mean relatedness and dyad relatedness within groups. In the wild, winter populations were found to be more highly related than expected by chance. Fifty-seven percent of animals were associated with a highly related individual in their winter aggregation. We show that southern flying squirrels have a preference for relatives as winter nest mates.
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mechanisms of cache retrieval in the group nesting southern flying squirrel Glaucomys volans
Ethology, 2006Co-Authors: Michael F Winterrowd, Peter D WeiglAbstract:We examined the proximate mechanisms of cache retrieval in the group-living, southern flying squirrel, Glaucomys volans, through a series of behavioral experiments conducted in a large indoor arena. The effectiveness of several retrieval mechanisms was determined including spatial memory, olfaction, random searching and a heuristic under different environmental conditions. Our goal was to elucidate the hoarding strategy of individuals in a nest group and to address whether food storing individuals possess a retrieval advantage over pilfering nestmates. A storer's retrieval advantage is necessary for scatter hoarding to be an evolutionarily stable strategy (ESS) within aggregations of unrelated individuals. Our previous work has shown that, G. volans lives in such groups, and consequently it was important to address the storer's retrieval advantage under a range of environmental conditions. Initially in our baseline experiment, we developed methods to eliminate olfactory-based retrieval and to control for random searching. Subsequently, we experimentally determined the effectiveness of cache retrieval via spatial memory, a heuristic and olfaction. We examined the mechanisms of cache retrieval in three additional experiments using two independent subject populations and found that under dry, odorless conditions spatial memory was the most effective retrieval mechanism in support of a storer's retrieval advantage. In a fifth experiment we examined cache retrieval under wet environmental conditions and showed that olfactory-based retrieval was effective and the storer's advantage was reduced. We interpret these laboratory results based on considerations of natural environmental conditions and game theory. We propose a conditional ESS strategy where animals store and retrieve their own caches as the primary food hoarding tactic and opportunistically pilfer caches as a secondary tactic.
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RELATEDNESS WITHIN NEST GROUPS OF THE SOUTHERN FLYING SQUIRREL USING MICROSATELLITE AND DISCRIMINANT FUNCTION ANALYSES
Journal of Mammalogy, 2005Co-Authors: Michael F Winterrowd, Kevin S Laves, William F. Gergits, Peter D WeiglAbstract:Genetic relationships were examined among wild-caught southern flying squirrels (Glaucomys volans) sharing the same natural nest cavity. Under natural conditions, typically 75‐80% of southern flying squirrel nest groups comprise adult-aged individuals. The remainder nest in family-based groups or are solitary. The coefficient of relatedness within nest groups of adult individuals and family-based nest groups was examined through microsatellite DNA analysis. Family or adult nest groups were identified from the age class of individual group members determined through a discriminant function analysis based on body mass. From this information, nest groups were categorized as family-based groups comprising a single adult female with nestlings, adult groups comprising adult aged-individuals, or subadult nest groups. The average coefficient of relatedness was determined in each nest group. Within the putative family groups, most individuals were 1st-order relatives. In the adult nest groups, the coefficient of relatedness was low, indicating that these individuals were unrelated. The relationships within the subadult nest groups were intermediate. This is the 1st study to show that adult nestmate southern flying squirrels typically are unrelated and do not nest in family-based groups.
Thomas S Risch - One of the best experts on this subject based on the ideXlab platform.
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Does gliding when pregnant select for larger females
Journal of Zoology, 2008Co-Authors: H. B. Fokidis, Thomas S RischAbstract:For terrestrial vertebrates, gliding imposes unique constraints on the interaction of body mass and structural size, particularly with reference to minimizing wing loading. Females of gliding animals experience increases in wing loading during pregnancy or gravidity, and selection may favour increased structural size to compensate for the added mass. We tested whether pregnant southern flying squirrels Glaucomys volans had similar wing loading as males, and whether females with lower wing loading bore heavier litters, than those with greater wing loading. Males had greater wing loading than females, regardless of the latter's reproductive state (males: 38.4±3.62 N m−2, pregnant females: 30.7±4.21 N m−2 and non-pregnant females: 26.8±5.13 N m−2). The slope of the linear relationship between planar surface area and body mass was similar between pregnant females and males, however (F=0.383, P=0.322). Thus female flying squirrels may optimize their litter mass to minimize wing loading during pregnancy. Contrary to our prediction, females with greater wing loading had heavier litters than those with lower wing loading, which suggests reproductive output may be influenced by other ecological factors.
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Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism
Animal Behaviour, 2007Co-Authors: H. Bobby Fokidis, Thomas S Risch, Travis C GlennAbstract:Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partly explain how female-biased sexual size dimorphism is maintained in this species.
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AN EXPERIMENTAL TEST OF SNAKE SKIN USE TO DETER NEST PREDATION
The Condor, 2006Co-Authors: Elizabeth C. Medlin, Thomas S RischAbstract:Abstract ABSTRACT Some bird species utilize snake skins as nesting material, possibly to decrease predation. We constructed 60 artificial nests simulating the nests of Great Crested Flycatchers (Myiarchus crinitus) in nest boxes to test the prediction that snake skins deter nest predators. Twenty of the boxes lacked rat snake (Elaphe obsoleta) skins (control), 20 had a single skin in the nest, and 20 had a skin in the nest and another displayed outside the box. Five of the control boxes were depredated (20%), while none of the experimental boxes were depredated. Our results supported our prediction that use of snake skins would deter mammalian predators, particularly the southern flying squirrel (Glaucomys volans). Although our results suggest a potential adaptive explanation for this behavior, our design did not allow us to address the degree of olfactory or visual detection by the squirrels, and left other potential explanations untested.
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Keeping tabs : Are redundant marking systems needed for rodents?
Wildlife Society Bulletin, 2006Co-Authors: H. Bobby Fokidis, Christy Robertson, Thomas S RischAbstract:We use survival analysis to compare failure of passive integrated transponder (PIT) tags and loss of metal ear tags in 2,277 southern flying squirrels (Glaucomys volans), 124 house mice (Mus musculus), 112 hispid cotton rats (Sigmodon hispidus), and 374 deer (Peromyscus maniculatus) and cotton mice (P. gossypinus). With the exception of cotton rats, failure rates between ear and PIT tags differed by species. Flying squirrels exhibited the highest proportional loss of both tag types and lost ear tags more readily than PIT tags failed. The opposite was true for cotton rats and deer and cotton mice. Most PIT tags appeared to fail shortly after implantation (≤3 days), except for flying squirrels and, to a lesser extent, cotton rats. Ear tags exhibited a consistent rate of loss in flying squirrels. Body mass did not influence failure of PIT tags; however, flying squirrel body mass was associated with increased loss of ear tags. For flying squirrels PIT tag failure increased with the number of times an individual had already received a PIT tag that failed. We provide recommendations for using PIT and ear tags in marking rodents based on species-specific patterns and suggest the combined use of external and internal markers to obtain the most reliable estimates of population parameters.
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The Use of Nest Boxes to Sample Arboreal Vertebrates
Southeastern Naturalist, 2005Co-Authors: H. Bobby Fokidis, Thomas S RischAbstract:Tree cavities are rarely incorporated into surveys of forest ecosystem biodiversity, due to difficultly in their systematic sampling. We examined the feasi- bility of using southern flying squirrel (Glaucomys volans Thomas) nest boxes for monitoring arboreal vertebrates at 11 sites within the Savannah River Site, SC. We recorded 3130 vertebrates of 11 species (3 mammals, 3 birds, 5 reptiles) using nest boxes for nesting, roosting, and foraging. G. volans represented the majority of these with 3019 individuals, but flying squirrel occupancy did not affect occupancy of boxes by other species. Upland hardwood forests had the most species that used boxes; however, due to uneven sampling, nest boxes placed in dense-canopy planta- tions detected the most species per box. We conclude that nest boxes are a useful means of surveying for cavity-dwelling species. We recommend a protocol that uses different size nest boxes at varying heights to accurately survey a traditionally under- sampled component of forest ecosystems, those species using tree cavities.
Paul J Wilson - One of the best experts on this subject based on the ideXlab platform.
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Climate change induced hybridization in flying squirrels
Global Change Biology, 2020Co-Authors: Colin J. Garroway, Jeff Bowman, Carolyn Grace Mahan, Michael A. Steele, Gregory G. Turner, Tara J. Cascaden, Gillian L. Holloway, Jay R. Malcolm, Paul J WilsonAbstract:There is now unequivocal evidence for global climate change; however, its potential impacts on evolutionary processes remain unclear. Many species have responded to contemporary climate change through shifts in their geographic range. This could lead to increased sympatry between recently diverged species; likely increasing the potential for hybridization. Recently, following a series of warm winters, southern flying squirrels (Glaucomys volans) in Ontario, Canada rapidly expanded their northern range limit resulting in increased sympatry with the closely related northern flying squirrel (Glaucomys sabrinus). This provided the opportunity to test the prediction that contemporary climate change can act as a catalyst creating conditions for the formation of hybrid zones. Following extensive sampling and molecular analyses (nuclear and mitochondrial DNA), we identified the occurrence of hybridization between sympatric G. sabrinus and G. volans. There was evidence of backcrossing but not of extensive introgession, consistent with the hypothesis of recent rather than historic hybridization. To our knowledge, this is the first report of hybrid zone formation following a range expansion induced by contemporary climate change. This is also the first report of hybridization between North American flying squirrel species.
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a test of non kin social foraging in the southern flying squirrel Glaucomys volans
Biological Journal of The Linnean Society, 2014Co-Authors: Meghan N Murrant, Jeff Bowman, Paul J WilsonAbstract:It can be challenging to understand the evolution of sociality, particularly the occurrence of co-operation by non-kin. Southern flying squirrels (Glaucomys volans) are an interesting example of non-kin co-operation because of the mutual benefits obtained by social thermoregulation during winter. Because group survival confers benefits to the entire group, flying squirrels may also follow an aggregation economy, whereby co-operative foraging during winter is advantageous. However, the extent of such social foraging in flying squirrels is unknown. We tested for social foraging of southern flying squirrels, and also for relatedness among foraging groups. To determine the structure of foraging groups, we set up and remotely monitored feeding stations and nest cavities. All squirrels at the study site were tagged with passive integrated transponder (PIT) tags and nests and feeding stations were monitored with automated PIT-tag recorders for a 24-month period. Squirrels were found most often foraging alone. Squirrels that were recorded foraging together comprised unrelated individuals that were also found to share nest cavities. Squirrels were also recorded travelling farther distances between nest cavity and feeding station in the winter season than in the summer season, suggesting that, during winter, squirrels trade-off proximity to food caches for membership in a nest group. Our data suggest that squirrels forage and cache alone in their summer home range and make solitary returns to this summer range to collect their cache during the winter months, despite exhibiting social winter nesting. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1126–1135.
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A test of non‐kin social foraging in the southern flying squirrel (Glaucomys volans)
Biological Journal of The Linnean Society, 2014Co-Authors: Meghan N Murrant, Jeff Bowman, Paul J WilsonAbstract:It can be challenging to understand the evolution of sociality, particularly the occurrence of co-operation by non-kin. Southern flying squirrels (Glaucomys volans) are an interesting example of non-kin co-operation because of the mutual benefits obtained by social thermoregulation during winter. Because group survival confers benefits to the entire group, flying squirrels may also follow an aggregation economy, whereby co-operative foraging during winter is advantageous. However, the extent of such social foraging in flying squirrels is unknown. We tested for social foraging of southern flying squirrels, and also for relatedness among foraging groups. To determine the structure of foraging groups, we set up and remotely monitored feeding stations and nest cavities. All squirrels at the study site were tagged with passive integrated transponder (PIT) tags and nests and feeding stations were monitored with automated PIT-tag recorders for a 24-month period. Squirrels were found most often foraging alone. Squirrels that were recorded foraging together comprised unrelated individuals that were also found to share nest cavities. Squirrels were also recorded travelling farther distances between nest cavity and feeding station in the winter season than in the summer season, suggesting that, during winter, squirrels trade-off proximity to food caches for membership in a nest group. Our data suggest that squirrels forage and cache alone in their summer home range and make solitary returns to this summer range to collect their cache during the winter months, despite exhibiting social winter nesting. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1126–1135.
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Northern range boundary dynamics of southern flying squirrels: evidence of an energetic bottleneck
Canadian Journal of Zoology, 2005Co-Authors: Jeff Bowman, Gillian L. Holloway, Jay R. Malcolm, Kevin R. Middel, Paul J WilsonAbstract:We undertook a large-scale survey of the distribution of northern, Glaucomys sabrinus (Shaw, 1801), and southern, Glaucomys volans (L., 1758), flying squirrels in Ontario, Canada. Livetrapping was conducted along a north- south transect spanning about 500 km, from 42.5°N to 47.2°N. During 2002-2004, we conducted 42 971 trap-nights at 26 sites and captured 232 northern and 538 southern flying squirrels. During 2002 and 2003, southern flying squirrels occurred >200 km farther north than we expected. However, the range of this species appeared to contract to the south by about 240 km after the winter of 2004. Weather and food data suggested that cold temperatures during January and February 2004 combined with a failed mast crop in the autumn of 2003 resulted in an energetic bottleneck and subse- quent population crash. We speculate that prior to 2004 southern flying squirrels had expanded their geographic range in response to recent climate warming. In particular, the nine winters between 1994 and 2004 were relatively warm. By measuring the range expansion over this warm interval, we were able to estimate a rate of spread of 22 km per year, and a diffusion coefficient of 6.9 × 10 7 m 2 per generation.
Katherine K Thorington - One of the best experts on this subject based on the ideXlab platform.
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Persistence of southern flying squirrel winter aggregations: roles of kinship, familiarity, and intruder squirrels
Journal of Mammalogy, 2011Co-Authors: Katherine K Thorington, Peter D WeiglAbstract:Abstract Southern flying squirrels (Glaucomys volans) are seasonally gregarious and rely on the thermoregulatory benefits of well-constructed nests and presence of nest mates to survive harsh winter conditions. Prior work has shown that kinship components are important to how winter aggregations form in captivity and that relatedness between individuals is higher than expected in undisturbed populations examined in the field. Over the course of 2 falls, 2006 and 2007, we created related and unrelated groups in a laboratory colony at Wake Forest University. We presented each group type with related and unrelated individuals as intruders. Once formed, aggregations persisted when presented with an intruder squirrel. Squirrels from existing aggregations were found in the same nest box 98% of the time. Factors of relatedness and familiarity were crucial in determining whether the intruder was accepted into an existing aggregation or nested alone. We found that related groups were more tolerant of truly novel (...
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Role of kinship in the formation of southern flying squirrel winter aggregations
Journal of Mammalogy, 2011Co-Authors: Katherine K Thorington, Peter D WeiglAbstract:In winter southern flying squirrels (Glaucomys volans) aggregate in large groups. They live on food items individually stored during the fall in their overlapping home ranges. The squirrels gain thermoregulatory benefits from living in aggregations but also face costs of group living, especially nest mates pilfering individually stored food. Other costs include increased predator attraction and a greater vulnerability to parasite infection. The presence of relatives in the group has the potential to increase inclusive fitness by increasing the availability of food, stored in the home area, to related individuals. Using 3 generations of known-relationship squirrels we conducted laboratory experiments to determine whether kin or familiar animals were preferred nest mates during aggregation formation. During 3 time periods, over 2 winters, squirrels were presented with kin and nonkin and familiar and unfamiliar animals and allowed to aggregate over the course of multiple 3-day trials. Kinship was persistently a major factor in the formation of aggregations. Squirrels aggregated with highly related animals (parents, offspring, and siblings) significantly more often than with unrelated animals. Familiarity became significant by the end of the study. Understanding how relatedness and familiarity interact in the formation of aggregations in seasonally gregarious animals sheds light on the processes and factors that lead to sociality.
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genetic relatedness in winter populations of seasonally gregarious southern flying squirrels Glaucomys volans
Journal of Mammalogy, 2010Co-Authors: Katherine K Thorington, Jackie D Metheny, Matina C Kalcounisrueppell, Peter D WeiglAbstract:Southern flying squirrels (Glaucomys volans) face a dilemma: winter aggregation is beneficial for thermoregulation but costly due to nest mates pilfering stored food in the home area and the tendency for groups to attract predators. Living with kin in winter aggregations may mitigate these deleterious effects because if an individual dies, its stored food can be beneficial to relatives, thereby increasing inclusive fitness. Southern flying squirrels from 7 populations and a captive colony were genotyped at 6 microsatellite loci. We calculated group mean relatedness and dyad relatedness within groups. In the wild, winter populations were found to be more highly related than expected by chance. Fifty-seven percent of animals were associated with a highly related individual in their winter aggregation. We show that southern flying squirrels have a preference for relatives as winter nest mates.
James F Taulman - One of the best experts on this subject based on the ideXlab platform.
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selection of nest trees by southern flying squirrels sciuridae Glaucomys volans in arkansas
Journal of Zoology, 1999Co-Authors: James F TaulmanAbstract:Natural nest-site selection was investigated in 50 radiocollared southern flying squirrels Glaucomys volans during spring and summer, 1994–1996, in the Ouachita National Forest of Arkansas. Squirrels nested in 226 trees in a variety of habitats at five study areas. Contrary to previous reports describing southern flying squirrels as habitat generalists, in this study squirrels showed selection in both the habitat and tree type in which nests were placed. Where it was available, mature pine–hardwood forest was selected for nesting. Young (< 15 years old) and immature (15–40 years old) pine plantations and harvested areas were avoided as nesting habitats. At harvested study areas, squirrels nested in protected riparian mature forest strips (greenbelt) along, and 10–20 m either side of, intermittent creeks and in adjacent mature forests. Squirrels constructed only outside nests in pine trees. In mature pine–hardwood forest, pines were used for outside nests more frequently than hardwoods; in greenbelt habitat, pines and hardwoods were chosen equally for outside nests. Both outside and cavity nests were found in hardwoods; standing dead trees (snags) contained only cavity nests. Snags were selected over hardwoods for cavity nesting in both mature pine–hardwood forest and greenbelt habitat. All hardwood species and all decay classes of snags were used for diurnal nesting in greater frequency than expected. Considering both cavity and outside nest-site selection, pines were used less than expected. Results suggest that mature forests are optimal flying squirrel nesting habitats and should be retained adjacent to harvested areas to provide resources to squirrels abandoning stands after disturbance. Within harvested areas, nesting habitat can be substantially improved through the retention of overstory hardwoods and snags, as well as protection of mature forest strips along drainages.