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Structural plasticity of olfactory neuropils in relation to insect diapause

1. Many insects that live in temperate zones spend the cold season in a state of dormancy, referred to as diapause. As the insect must rely on resources that were gathered before entering diapause, keeping a low metabolic rate is of utmost importance. Organs that are metabolically expensive to maint...

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Autores principales: Eriksson, Maertha, Janz, Niklas, Nylin, Sören, Carlsson, Mikael A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771155/
https://www.ncbi.nlm.nih.gov/pubmed/33391725
http://dx.doi.org/10.1002/ece3.7046
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author Eriksson, Maertha
Janz, Niklas
Nylin, Sören
Carlsson, Mikael A.
author_facet Eriksson, Maertha
Janz, Niklas
Nylin, Sören
Carlsson, Mikael A.
author_sort Eriksson, Maertha
collection PubMed
description 1. Many insects that live in temperate zones spend the cold season in a state of dormancy, referred to as diapause. As the insect must rely on resources that were gathered before entering diapause, keeping a low metabolic rate is of utmost importance. Organs that are metabolically expensive to maintain, such as the brain, can therefore become a liability to survival if they are too large. 2. Insects that go through diapause as adults generally do so before entering the season of reproduction. This order of events introduces a conflict between maintaining low metabolism during dormancy and emerging afterward with highly developed sensory systems that improve fitness during the mating season. 3. We investigated the timing of when investments into the olfactory system are made by measuring the volumes of primary and secondary olfactory neuropils in the brain as they fluctuate in size throughout the extended diapause life‐period of adult Polygonia c‐album butterflies. 4. Relative volumes of both olfactory neuropils increase significantly during early adult development, indicating the importance of olfaction to this species, but still remain considerably smaller than those of nondiapausing conspecifics. However, despite butterflies being kept under the same conditions as before the dormancy, their olfactory neuropil volumes decreased significantly during the postdormancy period. 5. The opposing directions of change in relative neuropil volumes before and after diapause dormancy indicate that the investment strategies governing structural plasticity during the two life stages could be functionally distinct. As butterflies were kept in stimulus‐poor conditions, we find it likely that investments into these brain regions rely on experience‐expectant processes before diapause and experience‐dependent processes after diapause conditions are broken. 6. As the shift in investment strategies coincides with a hard shift from premating season to mating season, we argue that these developmental characteristics could be adaptations that mitigate the trade‐off between dormancy survival and reproductive fitness.
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spelling pubmed-77711552020-12-31 Structural plasticity of olfactory neuropils in relation to insect diapause Eriksson, Maertha Janz, Niklas Nylin, Sören Carlsson, Mikael A. Ecol Evol Original Research 1. Many insects that live in temperate zones spend the cold season in a state of dormancy, referred to as diapause. As the insect must rely on resources that were gathered before entering diapause, keeping a low metabolic rate is of utmost importance. Organs that are metabolically expensive to maintain, such as the brain, can therefore become a liability to survival if they are too large. 2. Insects that go through diapause as adults generally do so before entering the season of reproduction. This order of events introduces a conflict between maintaining low metabolism during dormancy and emerging afterward with highly developed sensory systems that improve fitness during the mating season. 3. We investigated the timing of when investments into the olfactory system are made by measuring the volumes of primary and secondary olfactory neuropils in the brain as they fluctuate in size throughout the extended diapause life‐period of adult Polygonia c‐album butterflies. 4. Relative volumes of both olfactory neuropils increase significantly during early adult development, indicating the importance of olfaction to this species, but still remain considerably smaller than those of nondiapausing conspecifics. However, despite butterflies being kept under the same conditions as before the dormancy, their olfactory neuropil volumes decreased significantly during the postdormancy period. 5. The opposing directions of change in relative neuropil volumes before and after diapause dormancy indicate that the investment strategies governing structural plasticity during the two life stages could be functionally distinct. As butterflies were kept in stimulus‐poor conditions, we find it likely that investments into these brain regions rely on experience‐expectant processes before diapause and experience‐dependent processes after diapause conditions are broken. 6. As the shift in investment strategies coincides with a hard shift from premating season to mating season, we argue that these developmental characteristics could be adaptations that mitigate the trade‐off between dormancy survival and reproductive fitness. John Wiley and Sons Inc. 2020-11-18 /pmc/articles/PMC7771155/ /pubmed/33391725 http://dx.doi.org/10.1002/ece3.7046 Text en © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Eriksson, Maertha
Janz, Niklas
Nylin, Sören
Carlsson, Mikael A.
Structural plasticity of olfactory neuropils in relation to insect diapause
title Structural plasticity of olfactory neuropils in relation to insect diapause
title_full Structural plasticity of olfactory neuropils in relation to insect diapause
title_fullStr Structural plasticity of olfactory neuropils in relation to insect diapause
title_full_unstemmed Structural plasticity of olfactory neuropils in relation to insect diapause
title_short Structural plasticity of olfactory neuropils in relation to insect diapause
title_sort structural plasticity of olfactory neuropils in relation to insect diapause
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771155/
https://www.ncbi.nlm.nih.gov/pubmed/33391725
http://dx.doi.org/10.1002/ece3.7046
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