Basis of host recognition by the larval endoparasitoids : Cotesia sesamiae Cameron and Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) / Obonyo Amos Owino Meshack

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dc.contributor.author Meshack, Obonyo Amos Owino
dc.date.accessioned 2012-01-04T09:22:17Z
dc.date.available 2012-01-04T09:22:17Z
dc.date.issued 2009
dc.identifier.uri http://hdl.handle.net/10394/5005
dc.description Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2009.
dc.description.abstract Host recognition behaviour of two braconid larval parasitoids Cotesia sesamiae and Cotesia flavipes was studied using suitable stemborer hosts [i.e. Busseola fusca for C. sesamiae, and Chilo partellus for C. flavipes] and one non-host [Eldana saccharina]. The wasps displayed similar sequences of behavioural steps when locating their hosts largely depending on their antennae for host recognition and both antennae and tarsi for final host acceptance and oviposition. Tactile and contact chemoreception stimuli from the hosts seem to play a major role in oviposition decision by the parasitoids. In addition, the external morphology and distribution pattern of sensilla present on antennae, tarsi and ovipositor of the parasitoids were examined by scanning electron and optic microscopy after staining with silver nitrate. Three sensillar types were identified on the distal antennomeres: (i) non-porous sensilla trichoidea most probably involved in mechanoreception, (ii) uniporous sensilla chaetica likely to be gustatory and, (iii) multiporous sensilla placodea likely to be olfactory. The tarsi possess a few sensilla chaetica which could be gustatory while the manubrium is likely to be used in detection of vibrations. The distal end of the ovipositor bears numerous multiporous dome-shaped sensilla. Additionally, the ability of the wasps to discriminate between contact cues was studied. When host larvae were washed in distilled water the wasps did not insert their ovipositors. However, ovipositor insertion resumed when washed host or non-host larvae were painted with water extracts of their respective host larvae. The water extracts of the suitable hosts were more attractive to the wasps than those of non-hosts. Similarly, the frass is important in host recognition during short-range examination as those of respective hosts are more intensely antennated than of non-hosts. The parasitoids were able to discriminate the regurgitant of E. saccharina by not antennating the cotton wool ball of this host; while the regurgitant of B. fusca and C. partellus appeared not useful in discriminating between the two species for both parasitoid species. Further analysis suggests the presence of a protein(s) component(s) in the regurgitant possibly responsible for host recognition and oviposition by C. flavipes.
dc.language.iso en en_US
dc.publisher North-West University
dc.subject Braconidae en_US
dc.subject Busseola fusca en_US
dc.subject Chilo partellus en_US
dc.subject Cotesia flavipes en_US
dc.subject Cotesia sesamiae en_US
dc.subject Eldana saccharina en_US
dc.subject Host recognition en_US
dc.subject Kairomones en_US
dc.subject Lepidoptera en_US
dc.subject Parasitoids en_US
dc.subject Stemborers en_US
dc.title Basis of host recognition by the larval endoparasitoids : Cotesia sesamiae Cameron and Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) / Obonyo Amos Owino Meshack en_US
dc.type Thesis en_US
dc.description.thesistype Doctoral en_US

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