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Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms

Population densities of forest defoliating insects may be regulated by small mammal predation on the pupae. When outbreaks do occur, they often coincide with warm, dry weather and at barren forest sites. A proposed reason for this is that weather and habitat affect small mammal population density (n...

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Autores principales: Kollberg, Ida, Bylund, Helena, Huitu, Otso, Björkman, Christer
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4226841/
https://www.ncbi.nlm.nih.gov/pubmed/25234375
http://dx.doi.org/10.1007/s00442-014-3080-x
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author Kollberg, Ida
Bylund, Helena
Huitu, Otso
Björkman, Christer
author_facet Kollberg, Ida
Bylund, Helena
Huitu, Otso
Björkman, Christer
author_sort Kollberg, Ida
collection PubMed
description Population densities of forest defoliating insects may be regulated by small mammal predation on the pupae. When outbreaks do occur, they often coincide with warm, dry weather and at barren forest sites. A proposed reason for this is that weather and habitat affect small mammal population density (numerical response) and hence pupal predation. We propose an alternative explanation: weather and habitat affect small mammal feeding behaviour (functional response) and hence the outbreak risks of forest pest insects. We report results from laboratory and field-enclosure experiments estimating rates of pupal predation by bank voles (Myodes glareolus) on an outbreak insect, the European pine sawfly (Neodiprion sertifer), at different temperatures (15 and 20 °C), in different microhabitats (sheltered and non-sheltered), and with or without access to alternative food (sunflower seeds). We found that the probability of a single pupa being eaten at 20 °C was lower than at 15 °C (0.49 and 0.72, respectively). Pupal predation was higher in the sheltered microhabitat than in the open one, and the behaviour of the voles differed between microhabitats. More pupae were eaten in situ in the sheltered microhabitat whereas in the open area more pupae were removed and eaten elsewhere. Access to alternative food did not affect pupal predation. The results suggest that predation rates on pine sawfly pupae by voles are influenced by temperature- and habitat-induced variation in the physiology and behaviour of the predator, and not necessarily solely through effects on predator densities as previously proposed.
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spelling pubmed-42268412014-11-13 Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms Kollberg, Ida Bylund, Helena Huitu, Otso Björkman, Christer Oecologia Behavioral ecology - Original research Population densities of forest defoliating insects may be regulated by small mammal predation on the pupae. When outbreaks do occur, they often coincide with warm, dry weather and at barren forest sites. A proposed reason for this is that weather and habitat affect small mammal population density (numerical response) and hence pupal predation. We propose an alternative explanation: weather and habitat affect small mammal feeding behaviour (functional response) and hence the outbreak risks of forest pest insects. We report results from laboratory and field-enclosure experiments estimating rates of pupal predation by bank voles (Myodes glareolus) on an outbreak insect, the European pine sawfly (Neodiprion sertifer), at different temperatures (15 and 20 °C), in different microhabitats (sheltered and non-sheltered), and with or without access to alternative food (sunflower seeds). We found that the probability of a single pupa being eaten at 20 °C was lower than at 15 °C (0.49 and 0.72, respectively). Pupal predation was higher in the sheltered microhabitat than in the open one, and the behaviour of the voles differed between microhabitats. More pupae were eaten in situ in the sheltered microhabitat whereas in the open area more pupae were removed and eaten elsewhere. Access to alternative food did not affect pupal predation. The results suggest that predation rates on pine sawfly pupae by voles are influenced by temperature- and habitat-induced variation in the physiology and behaviour of the predator, and not necessarily solely through effects on predator densities as previously proposed. Springer Berlin Heidelberg 2014-09-19 2014 /pmc/articles/PMC4226841/ /pubmed/25234375 http://dx.doi.org/10.1007/s00442-014-3080-x Text en © The Author(s) 2014 https://creativecommons.org/licenses/by/4.0/ Open AccessThis article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.
spellingShingle Behavioral ecology - Original research
Kollberg, Ida
Bylund, Helena
Huitu, Otso
Björkman, Christer
Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title_full Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title_fullStr Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title_full_unstemmed Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title_short Regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
title_sort regulation of forest defoliating insects through small mammal predation: reconsidering the mechanisms
topic Behavioral ecology - Original research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4226841/
https://www.ncbi.nlm.nih.gov/pubmed/25234375
http://dx.doi.org/10.1007/s00442-014-3080-x
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