title: Tritrophic interactions between parasitoids and cereal aphids are mediated by nitrogen fertilizer.
abstract: Host plant nutritional quality can directly and indirectly affect the third trophic levels. The aphid-parasitoid relationship provides an ideal system to investigate tritrophic interactions (as the parasitoids are completely dependent for their development upon their hosts) and assess the bottom up forces operating at different concentrations of nitrogen applications. The effects of varying nitrogen fertilizer on the performance of Aphidius colemani (V.) reared on Sitobion avenae (F.) and Aphidius rhopalosiphi (D.) reared on Rhopalosiphum padi (L.) were measured. Parasitism and percent emergence of parasitoids were positively affected by nitrogen fertilizer treatments while developmental duration (egg, larval, and pupal stages) was not affected by increasing nitrogen inputs. In males and females of both parasitoid species, adult longevity increased with the increasing nitrogen fertilizer. Hind tibia length and mummy weight of both parasitoid species increased with nitrogen fertilizer concentrations, as a result of larger aphids. This study showed that nitrogen application to the soil can have important consequences for aboveground multitrophic interactions.
authors.affiliation: Division of Biology, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK.|University College of Agriculture.
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Aqueel
authors.affiliation: University College of Agriculture.
authors.forename: Abu-bakar M
authors.initials: AB
authors.lastname: Raza
authors.affiliation: University College of Agriculture.
authors.forename: Rashad M
authors.initials: RM
authors.lastname: Balal
authors.affiliation: University College of Agriculture.
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Shahid
authors.affiliation: Department of Biological Sciences, University of Sargodha, Pakistan.
authors.forename: Irfan
authors.initials: I
authors.lastname: Mustafa
authors.affiliation: University College of Agriculture.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Javaid
authors.affiliation: Division of Biology, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK.|Department of Crop and Environment Sciences, Harper Adams University, Shropshire, TF10 8NB, UK.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Leather
mesh_terms: D000818:Animals; D001042:Aphids / Q000469:parasitology*; D002523:Edible Grain / Q000378:metabolism; D005260:Female; D005308:Fertilizers; D020387:Food Chain; D006790:Host-Parasite Interactions / Q000187:drug effects*; D008136:Longevity; D008297:Male; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology*; D012744:Sex Ratio; D014863:Wasps / Q000187:drug effects* / Q000254:growth & development
chemical_list: D005308:Fertilizers; D009584:Nitrogen
keywords: cereal aphid parasitoids; nitrogen fertilization; tritrophic interactions