Environmental Entomology (2015) 44, 480-487

Sara Ruschioni, Paola Riolo, Nunzio Isidoro, Roberto Romani, Edoardo Petrucco-Toffolo, Daniel Zovi and Andrea Battisti (2015)
Contrasting patterns of host adaptation in two egg parasitoids of the pine processionary moth (Lepidoptera: Thaumetopoeidae)
Environmental Entomology 44 (3), 480-487
Abstract: Adaptation of parasitoids to their phytophagous host is often mediated by environmental conditions and by the food plant of the phytophagous host. Therefore, the host food plant can indirectly affect the survival and fitness of parasitoids that also attack quiescent host stages, such as eggs, in which the resources available to the immature parasitoid stages are limited. Our aim was to investigate how two egg parasitoid species of the pine processionary moth, Thaumetopoea pityocampa (Denis and Schiffermüller), respond to variations in egg traits at the extremes of a west-to-east geographic gradient in northern Italy. We considered one specialist [Baryscapus servadeii (Domenichini)] and one generalist [Ooencyrtus pityocampae (Mercet)] parasitoid, which reproduce mainly by thelytokous parthenogenesis and are common throughout the whole range of this pest. The size and shell structure of the pine processionary moth eggs were studied under light microscopy and tested experimentally under controlled conditions. We can conclude that 1) the pine processionary moth egg shell thickness is inversely proportional to the parasitism performance; 2) the larger eggs from the pine processionary moth eastern population produce parasitoid females of a larger size, which have greater realized fecundity; 3) the generalist parasitoid performs successfully with either the "home" or "away" (i.e., from both extremes of the geographic gradient) pine processionary moth eggs, which is not the case for the specialist parasitoid. The implications of these responses in the regulation of phytophagous populations are numerous and should be considered in population dynamics studies and pest management programs.
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Link to article at publishers website
Database assignments for author(s): Paola Riolo, Andrea Battisti, Roberto Romani

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Thaumetopoea pityocampa		Italy
Ooencyrtus pityocampae (parasitoid)	Thaumetopoea pityocampa		Italy
Baryscapus servadeii (parasitoid)	Thaumetopoea pityocampa		Italy