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Responses to oilseed rape and cotton volatiles in insect herbivores and parasitoids

Jönsson, Martin (2005). Responses to oilseed rape and cotton volatiles in insect herbivores and parasitoids. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2005:14
ISBN 91-576-7013-7
[Doctoral thesis]

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This thesis investigates the role of volatiles produced by oilseed rape (Brassica napus L.) and cotton (Gossypium hirsutum L.) in interactions with insects. It includes studies on release of volatiles by these two crops, as well as behavioural and electrophysiological responses to these odours by two pest insects and insect natural enemies. The pollen beetle, Meligethes aeneus is an important pest of Brassica oilseed crops. The larvae feed only on buds and flowers of these plants. The behavioural responses of adult beetles to odours of oilseed rape in bud and flowering stage, as well as to the colours green and yellow, were shown to assist the beetles in finding host plants. Olfactory and visual stimuli were found to interact and the responses of over-wintered and summer generation beetles differed in that the summer generation had a higher preference for flower odours and for flower odours in combination with the colour yellow. We found that oilseed rape infested by pollen beetles released a volatile blend different from that released by non-infested plants. Three of the most important parasitoids attacking pollen beetles are Phradis interstitialis, P. morionellus and Tersilochus heterocerus. Studies on the responses of these species to odours of bud and flowering stage oilseed rape and to colours showed that odours were used to discriminate between the plant stages, but colour was also important. Differences in host and plant stage preferences were observed in the field and such differences in behaviour are probably important for niche segregation and co-existence of the three parasitoid species. Electrophysiological responses to volatiles characteristic of damaged oilseed rape were also observed and all three species discriminated between infested and non-infested rape by odour. The moth Spodoptera littoralis is a polyphagous herbivore and an important pest of cotton. Responses of female antennae to odours were investigated using two different techniques. High sensitivity to different types of cotton odours were observed, among these several compounds known to be specifically induced by larval feeding. The effects of volatiles of plants infested by conspecific larvae were tested in two types of bioassay. The results indicated that odours from infested plants deterred oviposition, but females needed to perceive other plant stimuli for this discrimination. These studies of two crop plant systems show that plant volatiles affect insects on several trophic levels and confirm that odours often interact with other plant stimuli in shaping insect behaviour.

Authors/Creators:Jönsson, Martin
Title:Responses to oilseed rape and cotton volatiles in insect herbivores and parasitoids
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :February 2005
Number of Pages:42
ALLI. Jönsson, M., Rosdahl, K. & Anderson, P. 2005. Comparison of responses to olfactory and visual host plant cues between over-wintered and summer generation of pollen beetles (Meligethes aeneus). Manuscript. II. Jönsson, M., Lindkvist, A. & Anderson, P. 2005. Behavioural responses in three ichneumonid pollen beetle parasitoids to volatiles emitted from different phenological stages of oilseed rape. Accepted for publication in Entomologia Experimentalis et Applicata. III. Jönsson, M., Nilsson, C., Åhman, B., Hacker, N. & Anderson, P. 2005. Microhabitat distribution and discrimination of odours from infested oilseed rape by three pollen beetle parasitoids. Submitted manuscript. IV. Jönsson, M. & Anderson, P. 2005. Emission of oilseed rape volatiles after pollen beetle infestation; Electrophysiological and behavioural responses in the parasitoid Phradis morionellus. Submitted manuscript. V. Jönsson, M. & Anderson, P. 1999. Electrophysiological response to herbivoreinduced host plant volatiles in the moth Spodoptera littoralis. Physiological Entomology 24, 377-385. VI. Jönsson, M. & Anderson, P. 2005. Context dependent avoidance of volatiles from infested cotton plants by ovipositing Spodoptera littoralis. Manuscript.
Place of Publication:Alnarp
ISBN for printed version:91-576-7013-7
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H10 Pests of plants
Subjects:Not in use, please see Agris categories
Agrovoc terms:brassica napus, gossypium hirsutum, hot plants, volatility, coleoptera, hymneoptera, lepidoptera, olfaction
Keywords:insecta, semiochemicals, olfaction, olfactometer, niche segregation, host plant, odour detection, Coleoptera, Hymenoptera, Lepidoptera
Permanent URL:
ID Code:754
Department:(NL, NJ) > Institutionen för växtvetenskap
Deposited By: Martin Jönsson
Deposited On:07 Feb 2005 00:00
Metadata Last Modified:02 Dec 2014 10:07

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