The Experts below are selected from a list of 405 Experts worldwide ranked by ideXlab platform
Weston J Gray - One of the best experts on this subject based on the ideXlab platform.
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dispatches from the neighborhood watch using citizen science and field survey data to document color morph frequency in space and time
Ecology and Evolution, 2020Co-Authors: Richard M Lehtinen, Brian M Carlson, Alyssa R Hamm, Alexis G Riley, Maria M Mullin, Weston J GrayAbstract:: Heritable color polymorphisms have a long history of study in evolutionary biology, though they are less frequently examined today than in the past. These systems, where multiple discrete, visually identifiable color phenotypes co-occur in the same population, are valuable for tracking evolutionary change and ascertaining the relative importance of different evolutionary mechanisms. Here, we use a combination of citizen science data and field surveys in the Great Lakes region of North America to identify patterns of color morph frequencies in the Eastern Gray Squirrel (Sciurus carolinensis). Using over 68,000 individual Squirrel records from both large and small spatial scales, we identify the following patterns: (a) the melanistic (black) phenotype is often localized but nonetheless widespread throughout the Great Lakes region, occurring in all states and provinces sampled. (b) In Ohio, where intensive surveys were performed, there is a weak but significantly positive association between color morph frequency and geographic proximity of populations. Nonetheless, even nearby populations often had radically different frequencies of the melanistic morph, which ranged from 0% to 96%. These patterns were mosaic rather than clinal. (c) In the Wooster, Ohio population, which had over eight years of continuous data on color morph frequency representing nearly 40,000 records, we found that the frequency of the melanistic morph increased gradually over time on some survey routes but decreased or did not change over time on others. These differences were statistically significant and occurred at very small spatial scales (on the order of hundreds of meters). Together, these patterns are suggestive of genetic drift as an important mechanism of evolutionary change in this system. We argue that studies of color polymorphism are still quite valuable in advancing our understanding of fundamental evolutionary processes, especially when coupled with the growing availability of data from citizen science efforts.
Robert K Swihart - One of the best experts on this subject based on the ideXlab platform.
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segregating the effects of seed traits and common ancestry of hardwood trees on Eastern Gray Squirrel foraging decisions
PLOS ONE, 2015Co-Authors: Mekala Sundaram, Michael A. Steele, Janna R Willoughby, Nathanael I Lichti, Robert K SwihartAbstract:The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to Eastern Gray Squirrels (Sciurus carolinensis), and measured the time and distance travelled by Squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27–73%), and combined effects of seed traits and phylogeny of hardwood trees (5–55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 “global” axes of traits that were phylogenetically autocorrelated at the family and genus level and a third “local” axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30–76% of the variation in Squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four Squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak or more diffuse coevolutionary relationship between rodents and hardwood trees rather than a direct coevolutionary relationship.
Richard M Lehtinen - One of the best experts on this subject based on the ideXlab platform.
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dispatches from the neighborhood watch using citizen science and field survey data to document color morph frequency in space and time
Ecology and Evolution, 2020Co-Authors: Richard M Lehtinen, Brian M Carlson, Alyssa R Hamm, Alexis G Riley, Maria M Mullin, Weston J GrayAbstract:: Heritable color polymorphisms have a long history of study in evolutionary biology, though they are less frequently examined today than in the past. These systems, where multiple discrete, visually identifiable color phenotypes co-occur in the same population, are valuable for tracking evolutionary change and ascertaining the relative importance of different evolutionary mechanisms. Here, we use a combination of citizen science data and field surveys in the Great Lakes region of North America to identify patterns of color morph frequencies in the Eastern Gray Squirrel (Sciurus carolinensis). Using over 68,000 individual Squirrel records from both large and small spatial scales, we identify the following patterns: (a) the melanistic (black) phenotype is often localized but nonetheless widespread throughout the Great Lakes region, occurring in all states and provinces sampled. (b) In Ohio, where intensive surveys were performed, there is a weak but significantly positive association between color morph frequency and geographic proximity of populations. Nonetheless, even nearby populations often had radically different frequencies of the melanistic morph, which ranged from 0% to 96%. These patterns were mosaic rather than clinal. (c) In the Wooster, Ohio population, which had over eight years of continuous data on color morph frequency representing nearly 40,000 records, we found that the frequency of the melanistic morph increased gradually over time on some survey routes but decreased or did not change over time on others. These differences were statistically significant and occurred at very small spatial scales (on the order of hundreds of meters). Together, these patterns are suggestive of genetic drift as an important mechanism of evolutionary change in this system. We argue that studies of color polymorphism are still quite valuable in advancing our understanding of fundamental evolutionary processes, especially when coupled with the growing availability of data from citizen science efforts.
Mekala Sundaram - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Segregating the Effects of Seed Traits and Common Ancestry of Hardwood Trees on Eastern Gray Squirrel Foraging Decisions
2016Co-Authors: Mekala Sundaram, Michael A. Steele, Janna R Willoughby, Nathanael I Lichti, K. SwihartAbstract:The evolution of specific seed traits in scatter-hoarded tree species often has been attrib-uted to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to Eastern Gray Squirrels (Sciurus carolinensis), and measured the time and distance travelled by Squirrels that consumed or cached each seed. We estimated 11 physi-cal and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27–73%), and combined effects of seed traits and phylogeny of hardwood trees (5–55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 “global ” axes of traits that were phylogenetically autocorre-lated at the family and genus level and a third “local ” axis in which traits were not phyloge-netically autocorrelated. Collectively, these axes explained 30–76 % of the variation in Squirrel foraging investments. The first global pPCA axis, which produced large scores fo
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segregating the effects of seed traits and common ancestry of hardwood trees on Eastern Gray Squirrel foraging decisions
PLOS ONE, 2015Co-Authors: Mekala Sundaram, Michael A. Steele, Janna R Willoughby, Nathanael I Lichti, Robert K SwihartAbstract:The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to Eastern Gray Squirrels (Sciurus carolinensis), and measured the time and distance travelled by Squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27–73%), and combined effects of seed traits and phylogeny of hardwood trees (5–55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 “global” axes of traits that were phylogenetically autocorrelated at the family and genus level and a third “local” axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30–76% of the variation in Squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four Squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak or more diffuse coevolutionary relationship between rodents and hardwood trees rather than a direct coevolutionary relationship.
Michael A. Steele - One of the best experts on this subject based on the ideXlab platform.
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tamiasciurus mearnsi rodentia sciuridae
Mammalian Species, 2016Co-Authors: John L Koprowski, Michael A. Steele, Nicolas RamoslaraAbstract:Tamiasciurus mearnsi ([Townsend, 1897][1]) is a small-sized tree Squirrel commonly called Mearns’s Squirrel. One of 3 species that comprise the genus Tamiasciurus , T. mearnsi , is endemic to the Sierra de San Pedro Martir in Baja California, Mexico; it is considered rare and occurs only at low densities. T. mearnsi is federally listed as “Threatened” in Mexico and is also included in the International Union for the Conservation of Nature and Natural Resources Red List of Threatened Species as “Endangered.” The introduction of the Eastern Gray Squirrel ( Sciurus carolinensis ) may be a serious threat to this relict species. [1]: #ref-46
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RESEARCH ARTICLE Segregating the Effects of Seed Traits and Common Ancestry of Hardwood Trees on Eastern Gray Squirrel Foraging Decisions
2016Co-Authors: Mekala Sundaram, Michael A. Steele, Janna R Willoughby, Nathanael I Lichti, K. SwihartAbstract:The evolution of specific seed traits in scatter-hoarded tree species often has been attrib-uted to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to Eastern Gray Squirrels (Sciurus carolinensis), and measured the time and distance travelled by Squirrels that consumed or cached each seed. We estimated 11 physi-cal and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27–73%), and combined effects of seed traits and phylogeny of hardwood trees (5–55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 “global ” axes of traits that were phylogenetically autocorre-lated at the family and genus level and a third “local ” axis in which traits were not phyloge-netically autocorrelated. Collectively, these axes explained 30–76 % of the variation in Squirrel foraging investments. The first global pPCA axis, which produced large scores fo
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segregating the effects of seed traits and common ancestry of hardwood trees on Eastern Gray Squirrel foraging decisions
PLOS ONE, 2015Co-Authors: Mekala Sundaram, Michael A. Steele, Janna R Willoughby, Nathanael I Lichti, Robert K SwihartAbstract:The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to Eastern Gray Squirrels (Sciurus carolinensis), and measured the time and distance travelled by Squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27–73%), and combined effects of seed traits and phylogeny of hardwood trees (5–55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 “global” axes of traits that were phylogenetically autocorrelated at the family and genus level and a third “local” axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30–76% of the variation in Squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four Squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak or more diffuse coevolutionary relationship between rodents and hardwood trees rather than a direct coevolutionary relationship.