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Guerin, Patrick

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

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  • Publication
    MƩtadonnƩes 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
    MƩtadonnƩes 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
    AccĆØs libre
    Sensory and behavioural responses of the stable fly Stomoxys calcitrans to rumen volatiles
    (2007)
    Jeanbourquin, Philippe 
    ;
    Guerin, Patrick 
    Analysis of volatiles from rumen digesta by gas chromatography linked antennogram recordings from Stomoxys calcitrans (L) (Diptera: Muscidae) antennal receptor cells revealed about 30 electrophysiologically active constituents, the most important of which is dimethyl trisulphide with a sensory threshold in the femtogram range. The behavioural responses of S. calcitrans to five chemostimulants (dimethyl trisulphide, butanoic acid, p-cresol, oct-1-en-3-ol and skatole) were tested in a wind tunnel where activation and attraction of hungry flies to rumen volatiles were recorded. Dimethyl trisulphide, butanoic acid and p-cresol were found to attract S. calcitrans. This sensitivity to rumen volatile constituents, that also occur in animal wastes used for oviposition by Stomoxys spp., as well as in flowers used by stable flies as sources of nectar is discussed in the context of the behavioural ecology of these flies.
  • Publication
    AccĆØs libre
    Chemostimuli implicated in selection of oviposition substrates by the stable fly Stomoxys calcitrans
    (2007)
    Jeanbourquin, Philippe 
    ;
    Guerin, Patrick 
    Horse and cow dung were tested as substrates for oviposition by the stable fly Stomoxys calcitrans (L) (Diptera: Muscidae) in laboratory cages. Odour alone from either horse or cow dung was sufficient to attract flies for oviposition. This was confirmed in wind tunnel experiments, where both horse and cow dung were shown to attract gravid stable flies. However, when S. calcitrans was offered a choice between these two oviposition substrates, flies always chose horse dung over cow dung, both when allowed to contact the substrates and when relying on dung odour alone. Analyses of volatile compounds emanating from horse and cow dung by gas chromatography linked antennogram recordings from S. calcitrans antennae revealed no differences in the chemostimuli released from the two substrates. The predominant chemostimulant compounds in both substrates were carboxylic acids (butanoic acid), alcohols (oct-1-en-3-ol), aldehydes (decanal), ketones (octan-3-one), phenols (p-cresol), indoles (skatole), terpenes (Ī²-caryophyllene) and sulphides (dimethyl trisulphide). Higher levels (20ā€“40 p.p.m.) of carbon dioxide were recorded over horse dung compared with cow dung, a factor that may contribute to the preference exhibited by S. calcitrans for this substrate for oviposition.
  • Publication
    AccĆØs libre
    Ultrastructure and receptor cell responses of the antennal grooved peg sensilla of Triatoma infestans (Hemiptera : Reduviidae)
    (2003)
    Diehl, Peter-Allan 
    ;
    Vlimant, MichĆØle 
    ;
    Guerenstein, Pablo
    ;
    Guerin, Patrick 
    Ultrastructural examination of grooved-peg (GP) sensilla on the antenna of fifth instar Triatoma infestans nymphs by scanning electron microscopy and transmission electron microscopy reveal that they are 8-18 mum long with a diameter of about 2-2.8 mum at the non-articulated base. Some pegs have a terminal pore. These double-walled wall-pore (dw-wp) sensilla have an outer cuticular wall with 13-18 longitudinal grooves at the distal part of the peg. Groove channels are present at the bottom of the grooves from which radial spoke channels lead into the inner sensillum-lymph cavity. A dendrite sheath connects the tip of the thecogen cell to the inner cuticular wall thus forming separated outer and inner sensillum-lymph cavities. Four or five bipolar receptor cells are ensheathed successively within the GP sensilla by the thecogen cell, trichogen and tormogen cells. The inner dendritic segments of each sensory cell give rise at the ciliary constriction to an unbranched outer dendritic segment which can reach the tip of the sensillum. Electrophysiological recordings from the GP sensilla indicate that they house NH3, short-chain carboxylic acid and short-chain aliphatic amine receptor cells and can be divided into three functional sub-types (GP 1-3). All GP sensilla carry a receptor cell excited by aliphatic amines, such as isobutylamine, a compound associated with vertebrate odour. GP type 1 and 2 sensilla house, in addition, an NH3-excited cell whereas the type 2 sensilla also contains a short-chain carboxylic acid receptor. No cell particularly sensitive to either NH3 or carboxylic acids was found in the grooved-peg type 3 sensilla. GP types 1, 2 and 3 represent ca. 36, 10 and 43% of the GP sensilla, respectively, whereas the remaining 11% contain receptor cells that manifest normal spontaneous activity but do not respond to any of the afore mentioned stimuli. (C) 2003 Elsevier Science Ltd. All rights reserved.
  • Publication
    AccĆØs libre
    Olfactory and behavioural responses of the blood-sucking bug Triatoma infestans to odours of vertebrate hosts
    (2001)
    Guerenstein, Pablo G.
    ;
    Guerin, Patrick 
    Olfactory receptors in basiconic and grooved-peg sensilla on the antenna of fifth-instar Triatoma infestans nymphs respond to host odours. Gas chromatography analyses of host odour extracts coupled to electrophysiological recordings from basiconic sensillum receptors indicate that nonanal is a constituent of sheep wool and chicken feather odour that stimulates one of the receptors in this type of sensillum. Similar analyses revealed isobutyric acid in rabbit odour to be a chemostimulant for one of the receptors in grooved-peg sensilla. The response of the aldehyde receptor was higher to heptanal, octanal and nonanal than to other aliphatic aldehydes, and the response of the acid receptor was higher to isobutyric acid than to other short-chain branched and unbranched acids. The behavioural responses of fifth-instar T. infestans nymphs to nonanal and isobutyric acid in an air-stream on a servosphere indicate that, whereas nonanal causes activation of the bugs, isobutyric acid induces an increase in upwind displacement, i.e. odour-conditioned anemotaxis. Binary mixtures of these compounds did not improve the attraction obtained with isobutyric acid alone. A comparison of the behavioural and electrophysiological responses of the bugs to different amounts of isobutyric acid in air suggests that attraction is obtained at concentrations that causes low-to-moderate increases in the firing rate of the acid-excited receptor in the grooved-peg sensilla, whereas at a dose that evokes relatively high firing rates (>40 Hz) no attraction is obtained.
  • Publication
    AccĆØs libre
    Three-dimensional flight tracking shows how a visual target alters tsetse fly responses to human breath in a wind tunnel
    Gurba, Alexandre 
    ;
    Harraca, Vincent
    ;
    Perret, Jean-Luc
    ;
    Casera, Steve
    ;
    Donnet, StƩphane
    ;
    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.