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Recognition and modulation of olfactory signals in the noctuid moth spodoptera littoralis

Ahmed, Mohamed Saveer (2012). Recognition and modulation of olfactory signals in the noctuid moth spodoptera littoralis. Diss. (sammanfattning/summary) Alnarp, Sweden : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2012:98
ISBN 978-91-576-7745-7
[Doctoral thesis]

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Abstract

Food, mates and host plants are essential resources for plant-feeding insects. Optimal resource localization that fulfils the physiological need and reproductive goals of an insect is of utmost importance. Insects, like most animals, rely largely on the sense of smell to locate and evaluate potential resources that enhance their reproductive fitness. Confronted with a multitude of stimuli ranging from food to conspecifics, insects execute behavioural strategies that are strongly modulated by internal physiological factors such as hunger and reproductive status. In this thesis, I address how an insect’s reproductive state modulates olfactory perception and ultimately behaviour towards adult food, female sex pheromone and larval host plant odours.
The cotton leafworm Spodoptera littoralis is an appropriate species for studying modulation of olfactory perception and behaviour, since the chemical ecology and olfactory physiology of mate finding and host seeking is being thoroughly studied. Here, I show that mating in female S. littoralis causes transient reduction in the sexual receptivity, and a reduction in longevity. Mating induces physiological changes that strongly influence olfactory coding and preference in males and females that match their current physiological need. Following mating, female S. littoralis switches olfactory preference from adult food to egg-laying cues. Unmated female S. littoralis are highly attracted to lilac flowers (Syringa vulgaris). After mating, females switch their olfactory preference to the host plant cotton (Gossypium hirsutum). Remarkably, the behavioural switch from floral to green odours is also mirrored in the primary olfactory centre, the antennal lobe (AL). Further, I have identified odorants from cotton that elicit robust upwind flight responses in gravid female S. littoralis.
In male S. littoralis, mating transiently abolishes attraction to pheromone-releasing females and cotton volatiles that signal larval habitat and mating sites. This behavioural modulation is reflected in the peripheral and central olfactory system, the antenna and the AL. In contrast, behavioural and neuronal responses to lilac flowers that signal an adult food source are not influenced by mating status. These findings provide an excellent substrate to examine how neuronal circuits integrate external sensory information with physiological state to shape behaviour.

Authors/Creators:Ahmed, Mohamed Saveer
Title:Recognition and modulation of olfactory signals in the noctuid moth spodoptera littoralis
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :26 November 2012
Volume:2012:98
Number of Pages:40
Papers/manuscripts:
NumberReferences
IA. M. Saveer, P. G. Becher, G. Birgersson, B. S. Hansson, P. Witzgall and M. Bengtsson. Mate recognition and reproductive isolation between the sibling species Spodoptera littoralis and S. litura (submitted).
IIA. M. Saveer, S. H. Kromann, G. Birgersson, M. Bengtsson, T. Lindblom, A. Balkenius, B. S. Hansson, P. Witzgall, P. G. Becher and R. Ignell (2012). Floral to green: mating switches moth olfactory coding and preference. Proceedings of the Royal Society B 279(1737), 2314-2322.
IIIS. H. Kromann, A. M. Saveer, M. Binyameen, M. Bengtsson, G. Birgersson, B. S. Hansson, F. Schlyter, P. Witzgall, R. Ignell and P. G. Becher. Concurrent modulation of olfactory responses to sex and host plant cues in a male moth (manuscript).
IVA. M. Saveer, P. G. Becher, G. Birgersson, B. S. Hansson, M. Bengtsson and P. Witzgall. Upwind flight attraction of Spodoptera littoralis female moths to natural and synthetic cotton volatiles (manuscript).
Place of Publication:Alnarp, Sweden
Publisher:Dept. of Plant Protectiion Biology, Swedish University of Agricultural Science
ISBN for printed version:978-91-576-7745-7
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X30 Life sciences
Subjects:Obsolete subject words > NATURAL SCIENCES > Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Evolutionary Biology
Obsolete subject words > NATURAL SCIENCES > Biology > Terrestrial, freshwater and marine ecology > Ethology and behavioural ecology
Agrovoc terms:olfactory organs, spodoptera littoralis, spodoptera litura, reproductive performance, mating systems , sex pheromones, signals
Keywords:Spodoptera littoralis, Spodoptera litura, Olfaction, Modulation, Mating, Antennal lobe, Wind tunnel, Electrophysiology, Optical imaging
URN:NBN:urn:nbn:se:slu:epsilon-e-739
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-739
ID Code:9256
Department:(LTJ, LTV) > Department of Plant Protection Biology
External funders:FORMAS
Deposited By: Mr. Mohamed Saveer Ahmed
Deposited On:27 Nov 2012 10:00
Metadata Last Modified:02 Dec 2014 10:53

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