Disruption of an exotic mutualism can improve management of an invasive plant: varroa mite, honeybees and biological control of Scotch broom Cytisus scoparius in New Zealand

Paynter, Quentin, Main, Alanna, Gourlay, A. Hugh, Peterson, Paul G., Fowler, Simon V. and Buckley, Yvonne M. (2010) Disruption of an exotic mutualism can improve management of an invasive plant: varroa mite, honeybees and biological control of Scotch broom Cytisus scoparius in New Zealand. Journal of Applied Ecology, 47 2: 309-317. doi:10.1111/j.1365-2664.2010.01784.x


Author Paynter, Quentin
Main, Alanna
Gourlay, A. Hugh
Peterson, Paul G.
Fowler, Simon V.
Buckley, Yvonne M.
Title Disruption of an exotic mutualism can improve management of an invasive plant: varroa mite, honeybees and biological control of Scotch broom Cytisus scoparius in New Zealand
Formatted title
Disruption of an exotic mutualism can improve
management of an invasive plant: varroa mite,
honeybees and biological control of Scotch broom
Cytisus scoparius in New Zealand
Journal name Journal of Applied Ecology   Check publisher's open access policy
ISSN 0021-8901
1365-2664
1472-0043
Publication date 2010-04-01
Sub-type Article (original research)
DOI 10.1111/j.1365-2664.2010.01784.x
Volume 47
Issue 2
Start page 309
End page 317
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2011
Language eng
Subject C1
960405 Control of Pests, Diseases and Exotic Species at Regional or Larger Scales
050103 Invasive Species Ecology
Formatted abstract
1. A seed-feeding biocontrol agent Bruchidius villosus was released in New Zealand (NZ) to control the invasive European shrub, broom Cytisus scoparius, in 1988 but it was subsequently considered unable to destroy sufficient seed to suppress broom populations. We hypothesized that an invasive mite Varroa destructor, which has caused honeybee decline in NZ, may cause pollinator limitation, so that the additional impact of B. villosus might now reach thresholds for population suppression.

2. We performed manipulative pollination treatments and broad-scale surveys of pollination, seed rain and seed destruction by B. villosus to investigate how pollinator limitation and biocontrol interact throughout the NZ range of broom.

3. The effect of reduced pollination in combination with seed-destruction was explored using a population model parameterized for NZ populations.

4. Broom seed rain ranged from 59 to 21 416 seeds m−2 from 2004 to 2008, and was closely correlated with visitation frequency of honeybees and bumblebees. Infestation of broom seeds by B. villosus is expected to eventually reach 73% (the average rate observed at the localities adjacent to early release sites).

5. The model demonstrated that 73% seed destruction, combined with an absence of honeybee pollination, could cause broom extinction at many sites and, where broom persists, reduce the intensity of treatment required to control broom by conventional means.

6. Nevertheless, seed rain was predicted to be sufficient to maintain broom invasions over many sites in NZ, even in the presence of the varroa mite and B. villosus, largely due to the continued presence of commercial beehives that are treated for varroa mite infestation.

7. Synthesis and applications. Reduced pollination through absence of honeybees can reduce broom seed set to levels at which biocontrol can be more effective. To capitalize on the impact of the varroa mite on feral honeybees, improved management of commercial beehives (for example, withdrawal of licences for beekeepers to locate hives on Department of Conservation land) could be used as part of a successful integrated broom management programme at many sites in NZ.  © 2010 The Authors. Journal compilation © 2010 British Ecological Society.
Keyword Biological control
Bumblebee
Honeybee
Integrated weed management
Invasion
Varroa mite
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 11 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 28 Mar 2010, 10:04:20 EST