Ecology Letters (2000) 3, 469-474

G. Boivin and J. van Baaren (2000)
The role of larval aggression and mobility in the transition between solitary and gregarious development in parasitoid wasps
Ecology Letters 3 (6), 469-474
Abstract: Models explaining the appearance of gregariousness in insect parasitoids assume the presence of a tolerance gene that enables nonsiblicidal behaviour in gregarious larvae. Under this assumption, nontolerant individuals should attack and kill tolerant individuals when sharing a host, making this behaviour susceptible to invasion by nontolerant individuals. We propose an alternative hypothesis where gregarious larvae retain their aggressiveness but are less mobile. We tested this hypothesis with two sympatric and congeneric species of Mymaridae, Anaphes victus and Anaphes listronoti, respectively, solitary and gregarious egg parasitoids of a Curculionidae, Listronotus oregonensis. Results obtained in competition experiments and from direct observation of movement in mymariform larvae of both species support the reduced mobility hypothesis. By being immobile while retaining their fighting capacity, A. listronoti mymariform larvae appear to optimize host utilization through gregarious development, but can still defend themselves against sympatric aggressive species.
(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): Joan van Baaren, Guy Boivin

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
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.
	Listronotus oregonensis
Anaphes listronoti (parasitoid)	Listronotus oregonensis
Anaphes victus (parasitoid)	Listronotus oregonensis