Potential mechanisms driving population variation in spatial memory and the hippocampus in food-caching chickadees

Rebecca Croston, Carrie L. Branch, Dovid Y. Kozlovsky, Timothy C. Roth, Lara D. Ladage, Cody A. Freas, Vladimir V. Pravosudov

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the hypothesis that highly predictable differences in winter climate drive the evolution and maintenance of differences among populations both in cognition and in the brain via local adaptations, at least in food-caching parids.

Original languageEnglish (US)
Pages (from-to)354-371
Number of pages18
JournalIntegrative and comparative biology
Volume55
Issue number3
DOIs
StatePublished - Sep 1 2015

Fingerprint

hippocampus
spatial variation
cognition
winter
climate
epigenetics
natural selection
neurons
Poecile
brain
neurogenesis
geographical variation
foods
foraging
birds

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology
  • Plant Science

Cite this

Croston, Rebecca ; Branch, Carrie L. ; Kozlovsky, Dovid Y. ; Roth, Timothy C. ; Ladage, Lara D. ; Freas, Cody A. ; Pravosudov, Vladimir V. / Potential mechanisms driving population variation in spatial memory and the hippocampus in food-caching chickadees. In: Integrative and comparative biology. 2015 ; Vol. 55, No. 3. pp. 354-371.
@article{0aa302d6a4c640bb8f653086d9b69811,
title = "Potential mechanisms driving population variation in spatial memory and the hippocampus in food-caching chickadees",
abstract = "Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the hypothesis that highly predictable differences in winter climate drive the evolution and maintenance of differences among populations both in cognition and in the brain via local adaptations, at least in food-caching parids.",
author = "Rebecca Croston and Branch, {Carrie L.} and Kozlovsky, {Dovid Y.} and Roth, {Timothy C.} and Ladage, {Lara D.} and Freas, {Cody A.} and Pravosudov, {Vladimir V.}",
year = "2015",
month = "9",
day = "1",
doi = "10.1093/icb/icv029",
language = "English (US)",
volume = "55",
pages = "354--371",
journal = "Integrative and Comparative Biology",
issn = "1540-7063",
publisher = "Oxford University Press",
number = "3",

}

Potential mechanisms driving population variation in spatial memory and the hippocampus in food-caching chickadees. / Croston, Rebecca; Branch, Carrie L.; Kozlovsky, Dovid Y.; Roth, Timothy C.; Ladage, Lara D.; Freas, Cody A.; Pravosudov, Vladimir V.

In: Integrative and comparative biology, Vol. 55, No. 3, 01.09.2015, p. 354-371.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Potential mechanisms driving population variation in spatial memory and the hippocampus in food-caching chickadees

AU - Croston, Rebecca

AU - Branch, Carrie L.

AU - Kozlovsky, Dovid Y.

AU - Roth, Timothy C.

AU - Ladage, Lara D.

AU - Freas, Cody A.

AU - Pravosudov, Vladimir V.

PY - 2015/9/1

Y1 - 2015/9/1

N2 - Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the hypothesis that highly predictable differences in winter climate drive the evolution and maintenance of differences among populations both in cognition and in the brain via local adaptations, at least in food-caching parids.

AB - Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the hypothesis that highly predictable differences in winter climate drive the evolution and maintenance of differences among populations both in cognition and in the brain via local adaptations, at least in food-caching parids.

UR - http://www.scopus.com/inward/record.url?scp=84940844934&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940844934&partnerID=8YFLogxK

U2 - 10.1093/icb/icv029

DO - 10.1093/icb/icv029

M3 - Article

VL - 55

SP - 354

EP - 371

JO - Integrative and Comparative Biology

JF - Integrative and Comparative Biology

SN - 1540-7063

IS - 3

ER -