Entomologia Experimentalis et Applicata (2013) 147, 167-174

Thiago Oliveira Andrade, Maxime Hervé, Yannick Outreman, Liliane Krespi and Joan van Baaren (2013)
Winter host exploitation influences fitness traits in a parasitoid
Entomologia Experimentalis et Applicata 147 (2), 167-174
Abstract: Organisms can either evade winter's unfavourable conditions by migrating or diapausing, or endure them and maintain their activities. When it comes to foraging during winter, a period of scarce resources, there is strong selective pressure on resource exploitation strategy. Generalist parasitoids are particularly affected by this environmental constraint, as their fitness is deeply linked to the profitability of the available hosts. In this study, we considered a cereal aphid-parasitoid system and investigated (1) the host-parasitoid community structure, host availability, and parasitism rate in winter, (2) the influence of host quality in terms of species and instars on the fitness of the aphid parasitoid Aphidius rhopalosiphi De Stefani-Perez (Hymenoptera: Braconidae: Aphidiinae), and (3) whether there is a detectable impact of host fidelity on parasitism success of this parasitoid species. Host density was low during winter and the aphid community consisted of the species Rhopalosiphum padi L. and Sitobion avenae Fabricius (both Hemiptera: Aphididae), both parasitized by A. rhopalosiphi at non-negligible rates. Aphidius rhopalosiphi produced more offspring when parasitizing R. padi compared with S. avenae, whereas bigger offspring were produced when parasitizing S. avenae. Although aphid adults and old larvae were significantly larger hosts than young larvae, the latter resulted in higher emergence rates and larger parasitoids. No impact of host fidelity on emergence rates or offspring size was detected. This study provides some evidence that winter A. rhopalosiphi populations are able to take advantage of an array of host types that vary in profitability, indicating that host selectivity may drop under winter's unfavourable conditions.
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Link to article at publishers website
Database assignments for author(s): Maxime R. Hervé, Yannick Outreman, Joan van Baaren, Liliane Krespi

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
population dynamics/epizootiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sitobion avenae
	Rhopalosiphum padi
Aphidius rhopalosiphi (parasitoid)	Sitobion avenae
Aphidius rhopalosiphi (parasitoid)	Rhopalosiphum padi