Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry
Island rule describes the graded trend of gigantism in small‐bodied species to dwarfism in large‐bodied species inhabiting islands, but causal explanations remain unresolved. We used geometric morphometrics to quantify cranial morphology of 544 meadow vole Microtus pennsylvanicus samples across 11 i...
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crwiley:10.1111/oik.08777 2024-09-15T17:49:35+00:00 Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry Schlis‐Elias, Mariah C. Malaney, Jason L. 2022 http://dx.doi.org/10.1111/oik.08777 https://onlinelibrary.wiley.com/doi/pdf/10.1111/oik.08777 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/oik.08777 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Oikos volume 2022, issue 4 ISSN 0030-1299 1600-0706 journal-article 2022 crwiley https://doi.org/10.1111/oik.08777 2024-08-22T04:17:51Z Island rule describes the graded trend of gigantism in small‐bodied species to dwarfism in large‐bodied species inhabiting islands, but causal explanations remain unresolved. We used geometric morphometrics to quantify cranial morphology of 544 meadow vole Microtus pennsylvanicus samples across 11 island and 3 mainland populations from the Outer Lands of New England (Atlantic) and the Alexander Archipelago of Alaska (Pacific). We compared the thermoregulation and endurance (TRE) and ecological release (ER) hypotheses using all‐subsets linear models employing residual randomization permutation procedures (rrpp), and Akaike information criterion (AIC) for model selection. We decoupled direct and indirect effects of island variables on size using path analysis. We evaluated shape with principal components analysis (PCA) and Procrustes ANOVA on Procrustes shape coordinates, then assessed the impact of static allometry and TRE and ER variables on shape. Six Atlantic island populations exhibit significant signals of gigantism with the largest voles occurring on the smallest islands lacking predators. ER explains 63% of cranial size differences. Island area has a significant total effect on size by influencing the number of mammalian predators, resulting in a 0.011 increase in unit centroid size for a 100 km 2 decrease in island area. This corresponds to a predicted 0.9% change in size for every 100 km 2 . Given static allometry, cranial shape does not respond to insularity independent of size. These results suggest that island rule is a latent evolutionary process whose manifestation depends on nuanced biogeographic and ecological contexts that have important conservation and taxonomic implications. Article in Journal/Newspaper Archipelago Alaska Wiley Online Library Oikos 2022 4 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Island rule describes the graded trend of gigantism in small‐bodied species to dwarfism in large‐bodied species inhabiting islands, but causal explanations remain unresolved. We used geometric morphometrics to quantify cranial morphology of 544 meadow vole Microtus pennsylvanicus samples across 11 island and 3 mainland populations from the Outer Lands of New England (Atlantic) and the Alexander Archipelago of Alaska (Pacific). We compared the thermoregulation and endurance (TRE) and ecological release (ER) hypotheses using all‐subsets linear models employing residual randomization permutation procedures (rrpp), and Akaike information criterion (AIC) for model selection. We decoupled direct and indirect effects of island variables on size using path analysis. We evaluated shape with principal components analysis (PCA) and Procrustes ANOVA on Procrustes shape coordinates, then assessed the impact of static allometry and TRE and ER variables on shape. Six Atlantic island populations exhibit significant signals of gigantism with the largest voles occurring on the smallest islands lacking predators. ER explains 63% of cranial size differences. Island area has a significant total effect on size by influencing the number of mammalian predators, resulting in a 0.011 increase in unit centroid size for a 100 km 2 decrease in island area. This corresponds to a predicted 0.9% change in size for every 100 km 2 . Given static allometry, cranial shape does not respond to insularity independent of size. These results suggest that island rule is a latent evolutionary process whose manifestation depends on nuanced biogeographic and ecological contexts that have important conservation and taxonomic implications. |
format |
Article in Journal/Newspaper |
author |
Schlis‐Elias, Mariah C. Malaney, Jason L. |
spellingShingle |
Schlis‐Elias, Mariah C. Malaney, Jason L. Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
author_facet |
Schlis‐Elias, Mariah C. Malaney, Jason L. |
author_sort |
Schlis‐Elias, Mariah C. |
title |
Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
title_short |
Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
title_full |
Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
title_fullStr |
Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
title_full_unstemmed |
Island biogeography predicts skull gigantism and shape variation in meadow voles Microtus pennsylvanicus through ecological release and allometry |
title_sort |
island biogeography predicts skull gigantism and shape variation in meadow voles microtus pennsylvanicus through ecological release and allometry |
publisher |
Wiley |
publishDate |
2022 |
url |
http://dx.doi.org/10.1111/oik.08777 https://onlinelibrary.wiley.com/doi/pdf/10.1111/oik.08777 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/oik.08777 |
genre |
Archipelago Alaska |
genre_facet |
Archipelago Alaska |
op_source |
Oikos volume 2022, issue 4 ISSN 0030-1299 1600-0706 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/oik.08777 |
container_title |
Oikos |
container_volume |
2022 |
container_issue |
4 |
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1810291295427493888 |