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Guerin, Patrick

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Guerin, Patrick
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patrick.guerin@unine.ch
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https://libra.unine.ch/handle/123456789/310

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  • Publication
    Métadonnées seulement
    Three-dimensional flight tracking shows how a visual target alters tsetse fly responses to human breath in a wind tunnel
    (2012)
    Gurba, A.
    ;
    Harraca, V.
    ;
    Perret, J. L.
    ;
    Casera, S.
    ;
    Donnet, S.
    ;
    Guerin, Patrick 
    Tsetse flies Glossina spp. (Diptera; Glossinidae) are blood-feeding vectors of disease that are attracted to vertebrate hosts by odours and visual cues. Studies on how tsetse flies approach visual devices are of fundamental interest because they can help in the development of more efficient control tools. The responses of a forest tsetse fly species Glossina brevipalpis (Newstead) to human breath are tested in a wind tunnel in the presence or absence of a blue sphere as a visual target. The flight responses are video recorded with two motion-sensitive cameras and characterized in three dimensions. Although flies make meandering upwind flights predominantly in the horizontal plane in the plume of breath alone, upwind flights are highly directed at the visual target presented in the plume of breath. Flies responding to the visual target fly from take-off within stricter flight limits at lower ground speeds and with a significantly lower variance in flight trajectories in the horizontal plane. Once at the target, flies fly in loops principally in the horizontal plane within 40 cm of the blue sphere before descending in spirals beneath it. Successful field traps designed for G. brevipalpis take into account the strong horizontal component in local search behaviour by this species at objects. The results suggest that trapping devices should also take into account the propensity of G. brevipalpis to descend to the lower parts of visual targets.
  • Publication
    Métadonnées seulement
    Oriented responses of grapevine moth larvae Lobesia botrana to volatiles from host plants and an artificial diet on a locomotion compensator
    (2009)
    Becher, P. G.
    ;
    Guerin, Patrick 
    Larvae of the grapevine moth Lobesia botrana (Lepidoptera: Tortricidae) are a major pest of vine, Vitis vinifera. As larvae have limited energy reserves and are in danger of desiccation and predation an efficient response to plant volatiles that would guide them to food and shelter could be expected. The responses of starved 2nd or 3rd instar larvae to volatile emissions from their artificial diet and to single host plant volatiles were recorded on a locomotion compensator. Test products were added to an air stream passing over the 30 cm diameter servosphere. The larvae showed non-directed walks of low rectitude in the air stream alone but changed to goal-oriented upwind displacement characterised by relatively straight tracks when the odour of the artificial diet and vapours of methyl salicylate, 1-hexanol, (Z)-3-hexen-1-ol, terpinen-4-ol, 1-octen-3-ol, (E)-4,8-dimethyl-1,3,7-nonatriene and (Z)-3-hexenyl acetate were added to the air stream. This chemoanemotactic targeted displacement illustrates appetence for certain volatile cues from food by starved Lobesia larvae. Analysis of the larval behaviour indicates dose dependent responses to some of the host plant volatiles tested with a response to methyl salicylate already visible at 1 ng, the lowest source dose tested. These behavioural responses show that Lobesia larvae can efficiently locate mixtures of volatile products released by food sources as well as single volatile constituents of their host plants. Such goal-oriented responses with shorter travel time and reduced energy loss are probably of importance for larval survival as it decreases the time they are exposed to biotic and abiotic hazards. (C) 2009 Elsevier Ltd. All rights reserved.
  • Publication
    Métadonnées seulement
    Appetence behaviours of the triatomine bug Rhodnius prolixus on a servosphere in response to the host metabolites carbon dioxide and ammonia
    (2004)
    Otalora-Luna, F.
    ;
    Perret, J. L.
    ;
    Guerin, Patrick 
    A combination of 1,000 ppm CO2 plus 30-40 ppb NH3 in an air stream induced Rhodnius prolixus nymphs walking on a servosphere to perform a series of appetence behaviours. Shortly after the onset of stimulation the nymphs turned sharply upwind towards the source of the chemostimuli (within 13 +/- 9 s) from mostly downwind and crosswind walks in the air stream alone. The mean vector angles of these upwind tracks were concentrated in a cone 60degrees either side of due upwind. The upwind walking bugs stopped more frequently but for a shorter duration and walked at a higher speed than before stimulation. During stops in the presence of the chemostimuli the bugs frequently corrected their course angles and extended their forelegs to reach higher with their antennae in the air. In the air stream alone R. prolixus nymphs frequently sampled the sphere surface with the antennae and cleaned their antennae with the foreleg tarsi. However, the nymphs only briefly tapped the left or right antennal flagellum on the corresponding first leg tarsus and never touched the servosphere surface in the presence of the chemostimuli. After chemostimulus removal from the air stream the bugs continued to respond with the same appetence responses as during stimulation, but walked more tortuously in a crosswind direction in an effort to regain contact with the chemostimuli.
  • 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
    Influence of dose and ratio of mixtures of pheromone components on the attraction of the tropical bont tick, Amblyomma variegatum
    (: Slovak Academy Sciences Institute Zoology, 1999)
    McMahon, Conor
    ;
    Guerin, Patrick 
    ;
    Kazimirova, M
    ;
    Labuda, M
    ;
    Nuttall, Patricia
    The responses of Amblyomma variegatum adults to constituents of their aggregation-attraction pheromone presented in an air stream were studied using a locomotion compensator. Behaviours to vapours from two mixtures were compared, the first a 1:1 mixture of o-nitrophenol and methyl salicylate, the second a four component mixture (R) containing o-nitrophenol, methyl salicylate, 2,6 dichlorophenol and phenyl acetaldehyde in the ratio 10:10:2:1, respectively No difference was found between the kineses responses ofA. variegatum adults for either mixture: both elicited an increase in angular velocity and a reduction in speed, Moreover; attraction to vapours of either mixture was reduced significantly as the source dose was increased: both mixtures were good attractants at a source dose of 10 mug of the main components, but were not attractive at source doses 100 times higher. As with many other arthropods, A. variegatum adults are responsive to the ratio, as well as to the dose, of constituents in an attractant mix. We suggest that the quantity and ratios of compounds in attractive mixtures released from commercial dispensers should be measured before use in any control programme.