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Changes in host-parasitoid food web structure with elevation

Changes in host-parasitoid food web structure with elevation
Changes in host-parasitoid food web structure with elevation
Gradients in elevation are increasingly used to investigate how species respond to changes in local climatic conditions. Whilst many studies have shown elevational patterns in species richness and turnover, little is known about how food web structure is affected by elevation.

Contrasting responses of predator and prey species to elevation may lead to changes in food web structure. We investigated how the quantitative structure of a herbivore‐parasitoid food web changes with elevation in an Australian subtropical rain forest.

On four occasions, spread over 1 year, we hand‐collected leaf miners at twelve sites, along three elevational gradients (between 493 m and 1159 m a.s.l). A total of 5030 insects, including 603 parasitoids, were reared, and summary food webs were created for each site. We also carried out a replicated manipulative experiment by translocating an abundant leaf‐mining weevil Platynotocis sp., which largely escaped parasitism at high elevations (≥900 m a.s.l.), to lower, warmer elevations, to test if it would experience higher parasitism pressure.

We found strong evidence that the environmental change that occurs with increasing elevation affects food web structure. Quantitative measures of generality, vulnerability and interaction evenness decreased significantly with increasing elevation (and decreasing temperature), whilst elevation did not have a significant effect on connectance. Mined plant composition also had a significant effect on generality and vulnerability, but not on interaction evenness. Several relatively abundant species of leaf miner appeared to escape parasitism at higher elevations, but contrary to our prediction, Platynotocis sp. did not experience greater levels of parasitism when translocated to lower elevations.

Our study indicates that leaf‐mining herbivores and their parasitoids respond differently to environmental conditions imposed by elevation, thus producing structural changes in their food webs. Increasing temperatures and changes in vegetation communities that are likely to result from climate change may have a restructuring effect on host–parasitoid food webs. Our translocation experiment, however, indicated that leaf miners currently escaping parasitism at high elevations may not automatically experience higher parasitism under warmer conditions and future changes in food web structure may depend on the ability of parasitoids to adapt to novel hosts.
0021-8790
353-363
Maunsell, Sarah
5badf772-e391-4e5e-b041-8688199e18c4
Kitching, Roger
0e43a2f3-ac7b-42ba-9145-4d1648f07000
Burwell, Chris
27467d4e-5e0f-4d17-8dcb-9bd6dca829d8
Morris, Rebecca
f63d9be3-e08f-4251-b6a0-43b312d3997e
Maunsell, Sarah
5badf772-e391-4e5e-b041-8688199e18c4
Kitching, Roger
0e43a2f3-ac7b-42ba-9145-4d1648f07000
Burwell, Chris
27467d4e-5e0f-4d17-8dcb-9bd6dca829d8
Morris, Rebecca
f63d9be3-e08f-4251-b6a0-43b312d3997e

Maunsell, Sarah, Kitching, Roger, Burwell, Chris and Morris, Rebecca (2015) Changes in host-parasitoid food web structure with elevation. Journal of Animal Ecology, 84 (2), 353-363. (doi:10.1111/1365-2656.12285).

Record type: Article

Abstract

Gradients in elevation are increasingly used to investigate how species respond to changes in local climatic conditions. Whilst many studies have shown elevational patterns in species richness and turnover, little is known about how food web structure is affected by elevation.

Contrasting responses of predator and prey species to elevation may lead to changes in food web structure. We investigated how the quantitative structure of a herbivore‐parasitoid food web changes with elevation in an Australian subtropical rain forest.

On four occasions, spread over 1 year, we hand‐collected leaf miners at twelve sites, along three elevational gradients (between 493 m and 1159 m a.s.l). A total of 5030 insects, including 603 parasitoids, were reared, and summary food webs were created for each site. We also carried out a replicated manipulative experiment by translocating an abundant leaf‐mining weevil Platynotocis sp., which largely escaped parasitism at high elevations (≥900 m a.s.l.), to lower, warmer elevations, to test if it would experience higher parasitism pressure.

We found strong evidence that the environmental change that occurs with increasing elevation affects food web structure. Quantitative measures of generality, vulnerability and interaction evenness decreased significantly with increasing elevation (and decreasing temperature), whilst elevation did not have a significant effect on connectance. Mined plant composition also had a significant effect on generality and vulnerability, but not on interaction evenness. Several relatively abundant species of leaf miner appeared to escape parasitism at higher elevations, but contrary to our prediction, Platynotocis sp. did not experience greater levels of parasitism when translocated to lower elevations.

Our study indicates that leaf‐mining herbivores and their parasitoids respond differently to environmental conditions imposed by elevation, thus producing structural changes in their food webs. Increasing temperatures and changes in vegetation communities that are likely to result from climate change may have a restructuring effect on host–parasitoid food webs. Our translocation experiment, however, indicated that leaf miners currently escaping parasitism at high elevations may not automatically experience higher parasitism under warmer conditions and future changes in food web structure may depend on the ability of parasitoids to adapt to novel hosts.

Full text not available from this repository.

More information

Accepted/In Press date: 29 July 2014
e-pub ahead of print date: 20 October 2014
Published date: March 2015
Organisations: Biomedicine

Identifiers

Local EPrints ID: 407754
URI: http://eprints.soton.ac.uk/id/eprint/407754
ISSN: 0021-8790
PURE UUID: 75f89d71-f1b8-40c3-bd71-92f05c164023
ORCID for Rebecca Morris: ORCID iD orcid.org/0000-0002-0020-5327

Catalogue record

Date deposited: 25 Apr 2017 01:07
Last modified: 13 Mar 2020 01:39

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