Ecological Entomology (2008) 33, 464-472

Claire E. Rutledge, Sanford D. Eigenbrode and Hongjian Ding (2008)
A plant surface mutation mediates predator interference among ladybird larvae
Ecological Entomology 33 (4), 464-472
Abstract: 1. We investigated mechanisms causing predator-predator interference between fourth instar Hippodamia convergens larvae foraging for pea aphids on pea plants, Pisum sativum, with a wild-type wax bloom, and the lack of such interference between larvae foraging on pea plants with a reduced-wax bloom caused by the single gene mutation wel.
2. Observations showed that behavioural interactions between larvae were not affected by wax phenotype. Specifically, larvae did not encounter one another more frequently on normal-wax peas as may have been predicted because reduced ability by coccinellids to attach to normal-wax plant surfaces could restrict them to foraging on only some parts of these plants.
3. In a controlled bioassay on normal-wax peas, H. convergens larvae avoided leaflets previously exposed to another larva. On reduced-wax peas, this effect was not detected.
4. In microcosm experiments, inter-predator interference in terms of prey consumption occurred on normal-wax peas, but not on reduced-wax peas. The interference on normal-wax peas occurred whether two H. convergens larvae were placed on a pea aphid-infested, normal-wax plant simultaneously or sequentially.
5. We conclude that the observed inter-predator interference is not as a result of direct physical contact, but rather arises because of (i) inhibition of foraging by chemical trails left by other larvae, (ii) the inability of larvae to access portions of the normal-wax plants creating aphid refugia, or (iii) a combination of these factors.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Claire E. Rutledge, Sanford D. Eigenbrode

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
environment - cropping system/rotation
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Acyrthosiphon pisum	Pea (Pisum sativum)
Hippodamia convergens (predator)	Acyrthosiphon pisum	Pea (Pisum sativum)