Differential signalling from specialist and generalist Brassica feeding aphids to differentially adapted aphid parasitoids
Differential signalling from specialist and generalist Brassica feeding aphids to differentially adapted aphid parasitoids
Lipaphis erysimi (Kaltenbach) and Mysus persicae (Sulzer) are specialist and generalist brassica feeding aphids, respectively. The signalling from these aphid species feeding on turnip, Brassica rapa var rapifera, to aphid parasitoids has been studied chemically and behaviourally. The chemistry included analyses of glucosinolates, a major component of the secondary chemistry of brassicaceous plants and the effect of aphid infestation. The foliar glucosinolate content was not altered significantly by aphid infestation of the magnitude used in these experiments. The glucosinolate content of the two aphid species did significantly differ, with a clear sequestration of glucosinolates by L. erysimi, but not by M. persicae. Greater quantities of volatiles isothiocyanates, products of glucosinolate hydrolysis, were produced by aphid infested plants than clean aphid-free plants and M. persicae-infested plants produced greater quantities of isothiocynanate than L. erysimi-infested plants. The behavioural responses of aphid parasitoids to this chemistry were observed in a series of small scale laboratory bioassays designed to examine specific aspects of host foraging. Responses to volatiles produced by plant-aphid complexes and to synthetic isothiocyanates were explored in a series of Y-tube bioassays. Diaeretiella rapae (Mc’Intosh) oriented towards 3-butenyl isothiocyanate significantly more often than controls. The process of host acceptance by D. rapae, Aphidius colemani (Viereck) and Praon volucre (Haliday) were explored in attack rate bioassays. Diaeretiella rapae had a greater attack rate on L. erysimi than M. persicae irrespective of the original host, while A. colemani and P. volucre did not have a significant difference in attack rate on the two aphid species. Bioassays using D. rapae that had been excised from their mummy cases prior to emergence were used to examine the effect of emergence cues on attack rate.
University of Southampton
2004
Blande, James D
(2004)
Differential signalling from specialist and generalist Brassica feeding aphids to differentially adapted aphid parasitoids.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Lipaphis erysimi (Kaltenbach) and Mysus persicae (Sulzer) are specialist and generalist brassica feeding aphids, respectively. The signalling from these aphid species feeding on turnip, Brassica rapa var rapifera, to aphid parasitoids has been studied chemically and behaviourally. The chemistry included analyses of glucosinolates, a major component of the secondary chemistry of brassicaceous plants and the effect of aphid infestation. The foliar glucosinolate content was not altered significantly by aphid infestation of the magnitude used in these experiments. The glucosinolate content of the two aphid species did significantly differ, with a clear sequestration of glucosinolates by L. erysimi, but not by M. persicae. Greater quantities of volatiles isothiocyanates, products of glucosinolate hydrolysis, were produced by aphid infested plants than clean aphid-free plants and M. persicae-infested plants produced greater quantities of isothiocynanate than L. erysimi-infested plants. The behavioural responses of aphid parasitoids to this chemistry were observed in a series of small scale laboratory bioassays designed to examine specific aspects of host foraging. Responses to volatiles produced by plant-aphid complexes and to synthetic isothiocyanates were explored in a series of Y-tube bioassays. Diaeretiella rapae (Mc’Intosh) oriented towards 3-butenyl isothiocyanate significantly more often than controls. The process of host acceptance by D. rapae, Aphidius colemani (Viereck) and Praon volucre (Haliday) were explored in attack rate bioassays. Diaeretiella rapae had a greater attack rate on L. erysimi than M. persicae irrespective of the original host, while A. colemani and P. volucre did not have a significant difference in attack rate on the two aphid species. Bioassays using D. rapae that had been excised from their mummy cases prior to emergence were used to examine the effect of emergence cues on attack rate.
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Published date: 2004
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Local EPrints ID: 465278
URI: http://eprints.soton.ac.uk/id/eprint/465278
PURE UUID: a0acfc86-f2fa-450d-a8fb-8a6071e7d813
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Date deposited: 05 Jul 2022 00:34
Last modified: 05 Jul 2022 00:34
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Author:
James D Blande
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