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Guerin, Patrick

Nom
Guerin, Patrick
Affiliation principale
Site web
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Professeur associé
Email
patrick.guerin@unine.ch
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https://libra.unine.ch/handle/123456789/310

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  • Publication
    Métadonnées seulement
    Responses of the tropical bont tick, Amblyomma variegatum (Fabricius), to its aggregation-attachment pheromone presented in an air stream on a servosphere
    (2000)
    McMahon, Conor
    ;
    Guerin, Patrick 
    Male Amblyomma variegatum ticks feeding on a host release a mixture of o-nitrophenol and methyl salicylate which serves to attract conspecifics. The behavioural responses of A. variegatum on a servosphere to these volatiles presented in an air stream are detailed hers. In still air, ticks walked on all eight legs, but with long halts. In contrast, the air stream caused continuous walking and induced a reaching response where the forelegs actively sampled the air. Such reaching increased the angular velocity and reduced walking speed, effects that were amplified in the presence of vapours from o-nitrophenol and methyl salicylate in the air flowing over the ticks. Vapour from a 1:1 mixture of o-nitrophenol and methyl salicylate was attractive over a 10(4)-fold concentration range providing an increase in upwind displacement of 20-40%, significantly higher than the natural ratio where o-nitrophenol vapour predominates. Although the responses to o-nitrophenol vapour were variable when presented alone, this chemical was consistently attractive when delivered with steer hair odour - unattractive on its own. Moreover, the upwind walk to this combination did not cause a change in speed or angular velocity. This supports the hypothesis that the response to the pheromone is enhanced by host odour.
  • Publication
    Métadonnées seulement
    Contact chemostimuli in the mating behaviour of the cattle tick, Boophilus microplus
    (1998)
    De Bruyne, Marien
    ;
    Guerin, Patrick 
    Mating of the cattle tick Boophilus microplus is mediated by chemical stimuli on the cuticle of females. Males are arrested on the dorsum of females attached to the host, frequently sample the substrate, and then tip-over to the ventrally located gonopore. These behaviours are also observed in vitro when males are placed on a small glass bead treated with a female extract. Time spent and tip-ever by male ticks on dummies is used in an assay to test the behavioural significance of fractions of the extract. TLC separation yields one apolar fraction that arrests males, though much less so than the whole extract, but lost tip-over behaviour This apolar fi action contains a series of cholesteryl esters that, when tested individually, show no arrestment activity at levels present in the extract but, when combined, are as active as the fraction. When a small silica column is used for fractionation, all biological activity is reproduced after recombining the fractions. In addition to the early eluting apolar fraction containing cholesteryl esters, a set of highly active more polar fractions is isolated. Electrophysiological recordings from gustatory sensilla on the pedipalps of male B. microplus, which are regularly brought into contact with the cuticle of the female during mating, provide evidence for receptors in two of them responding to the whole extract and to the behaviourally active polar fractions. Mating behaviour involving arrestment and tip-over is clearly initiated by a mixture of chemical stimuli, and tip-over behaviour is associated with the more polar material. Arch. Insect Biochem. Physiol. 39:65-80, 1998. (C) 1998 Wiley-Liss, Inc.