The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Rickard Ignell - One of the best experts on this subject based on the ideXlab platform.
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Mosquito Host Seeking in 3D Using a Versatile Climate-Controlled Wind Tunnel System
Frontiers in behavioral neuroscience, 2021Co-Authors: Annika Hinze, Sharon R Hill, Jörgen Lantz, Rickard IgnellAbstract:Future anthropogenic climate change is predicted to impact sensory-driven behaviours. Building on recent improvements in computational power and tracking technology, we have developed a versatile climate-controlled wind tunnel system, in which to study the effect of climate parameters, including temperature, precipitation, and elevated greenhouse gas levels, on odour-mediated behaviours in insects. To establish a baseline for future studies, we here analysed the Host-Seeking behaviour of the major malaria vector mosquito, Anopheles gambiae sensu strico, to human odour and carbon dioxide (CO2), under tightly controlled climatic conditions, and isolated from potential background contamination by the presence of an experimenter. When presented with a combination of human foot odour and CO2 (case study I), mosquitoes engaged in faster crosswind flight, spent more time in the filamentous odour plume and targeted the odour source more successfully. In contrast, female An. gambiae s. s. presented with different concentrations of CO2 alone, did not display Host-Seeking behaviour (case study II). These observations support previous findings on the role of human Host-associated cues in Host Seeking and confirm the role of CO2 as a synergist, but not a Host-Seeking cue on its own. Future studies are aimed at investigating the effect of climate change on odour-mediated behaviour in mosquitoes and other insects. Moreover, the system will be used to investigate detection and processing of olfactory information in various behavioural contexts, by providing a fine-scale analysis of flight behaviour.
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Dengue infection modulates locomotion and Host Seeking in Aedes aegypti.
PLoS neglected tropical diseases, 2020Co-Authors: Anaïs Karine Tallon, Marcelo G. Lorenzo, Sharon R Hill, Luciano Andrade Moreira, Luis Villegas, Rickard IgnellAbstract:Pathogens may manipulate their human and mosquito Hosts to enhance disease transmission. Dengue, caused by four viral serotypes, is the fastest-growing transmissible disease globally resulting in 50–100 million infections annually. Transmission of the disease relies on the interaction between humans and the vector Aedes aegypti and is largely dependent on the odor-mediated Host Seeking of female mosquitoes. In this study, we use activity monitors to demonstrate that dengue virus-1 affects the locomotion and odor-mediated behavior of Ae. aegypti, reflecting the progression of infection within the mosquito. Mosquitoes 4–6 days post-infection increase locomotion, but do not alter their odor-driven Host-Seeking response. In contrast, females 14–16 days post-infection are less active, yet more sensitive to human odors as assessed by behavioral and electrophysiological assays. Such an increase in physiological and behavioral sensitivity is reflected by the antennal-specific increase in abundance of neural signaling transcripts in 14 days post-infection females, as determined by transcriptome analysis. This suggests that the sensitivity of the mosquito peripheral olfactory system is altered by the dengue virus by enhancing the overall neural responsiveness of the antenna, rather than the selective regulation of chemosensory-related genes. Our study reveals that dengue virus-1 enhances vector-related behaviors in the early stages post-infection that aid in avoiding predation and increasing spatial exploration. On the other hand, at the later stages of infection, the virus enhances the Host-Seeking capacity of the vector, thereby increasing the risk of virus transmission. A potential mechanism is discussed.
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Age-dependent regulation of Host Seeking in Anopheles coluzzii.
Scientific reports, 2019Co-Authors: Aman B. Omondi, Majid Ghaninia, M. Dawit, T. Svensson, Rickard IgnellAbstract:Behavioural attraction of the malaria vector Anopheles coluzzii to human Host odour increases during adult maturation. We have previously demonstrated that the onset of Host Seeking in An. coluzzii coincides with an increased sensitivity of the CO2-sensitive neurons and abundance of chemosensory receptor gene transcripts in the maxillary palp. In this study, we extend our analysis to the antenna. Functional characterisation of the near-complete repertoire of odorant receptors (Ors) expressed in this tissue, to fractioned human odour, reveals a subset of salient human odorants to be detected by Ors at physiological relevant concentrations. When presented as a blend in their ratio of natural emission, these odorants elicit attraction by Host-Seeking mosquitoes, emphasising that Ors alone can mediate this behaviour. However, the same blend inhibits attraction in teneral mosquitoes. This switch in behavioural response indicates a change in valence during adult maturation. Quantitative analysis of Or transcript abundance and in vivo electrophysiological analysis reveal that the olfactory system of female An. coluzzii undergoes concerted changes that correlate with the onset of Host Seeking. We conclude that changes in Or abundance modulate peripheral olfactory coding, resulting in ecologically relevant behavioural effects.
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Sex and age modulate antennal chemosensory-related genes linked to the onset of Host Seeking in the yellow-fever mosquito, Aedes aegypti.
Scientific reports, 2019Co-Authors: Anaïs Karine Tallon, Sharon R Hill, Rickard IgnellAbstract:The mosquito Aedes aegypti is the primary vector for the fastest growing infectious disease in the world, dengue fever. Disease transmission heavily relies on the ability of female mosquitoes to locate their human Hosts. Additionally, males may be found in close proximity to humans, where they can find mates. Host Seeking behaviour of both sexes is dependent on adult sexual maturation. Identifying the molecular basis for the onset of Host Seeking may help to determine targets for future vector control. In this study, we investigate modulation of the Host Seeking behaviour and the transcript abundance of the main chemoreceptor families between sexes and across ages in newly-emerged mosquitoes. Attraction to human odour was assessed using a Y-tube olfactometer, demonstrating that both males and females display age-dependent regulation of Host Seeking. The largest increase in transcript abundance was identified for select chemosensory genes in the antennae of young adult Ae. aegypti mosquitoes and reflects the increase in attraction to human odour observed between 1 and 3 day(s) post-emergence in both males and females. Future functional characterisation of the identified differentially abundant genes may provide targets for the development of novel control strategies against vector borne diseases.
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feeding induced changes in allatostatin a and short neuropeptide f in the antennal lobes affect odor mediated Host Seeking in the yellow fever mosquito aedes aegypti
PLOS ONE, 2017Co-Authors: Peter Christ, Anna Reifenrath, Jorg Kahnt, Frank Hauser, Sharon R Hill, Joachim Schachtner, Rickard IgnellAbstract:Aedes aegypti is a model species in which the endogenous regulation of odor-mediated Host Seeking behavior has received some attention. Sugar feeding and Host Seeking in female A. aegypti are transiently inhibited following a blood meal. This inhibition is partially mediated by short neuropeptide F (sNPF). The paired antennal lobes (ALs), as the first processing centers for olfactory information, has been shown to play a significant role in the neuropeptidergic regulation of odor-mediated behaviors in insects. The expression of sNPF, along with other peptides in the ALs of A. aegypti, indicate parallel neuromodulatory systems that may affect olfactory processing. To identify neuropeptides involved in regulating the odor-mediated Host Seeking behavior in A. aegypti, we use a semi-quantitative neuropeptidomic analysis of single ALs to analyze changes in the levels of five individual neuropeptides in response to different feeding regimes. Our results show that the level of sNPF-2, allatostatin-A-5 (AstA-5) and neuropeptide-like precursor-1-5 (NPLP-1-5), but not of tachykinin-related-peptides and SIFamide (SIFa), in the AL of female mosquitoes, changes 24 h and 48 h post-blood meal, and are dependent on prior access to sugar. To assess the role of these neuropeptides in modulating Host Seeking behavior, when systemically injected individually, sNPF-2 and AstA-5 significantly reduced Host Seeking behavior. However, only the injection of the binary mixture of the two neuropeptides lead to a Host Seeking inhibition similar to that observed in blood fed females. We conclude that modulation of the odor mediated Host Seeking behavior of A. aegypti is likely regulated by a dual neuropeptidergic pathway acting in concert in the ALs.
Renaud Lancelot - One of the best experts on this subject based on the ideXlab platform.
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Host-Seeking activity of bluetongue virus vectors: endo/exophagy and circadian rhythm of Culicoides in Western Europe.
PloS one, 2012Co-Authors: Elvina Viennet, Claire Garros, Ignace Rakotoarivony, Xavier Allene, Laëtitia Gardes, Jonathan Lhoir, Ivanna Fuentes, Roger Venail, Didier Crochet, Renaud LancelotAbstract:Feeding success of free-living hematophagous insects depends on their ability to be active when Hosts are available and to reach places where Hosts are accessible. When the hematophagous insect is a vector of pathogens, determining the components of Host-Seeking behavior is of primary interest for the assessment of transmission risk. Our aim was to describe endo/exophagy and circadian Host-Seeking activity of Palaearctic Culicoides species, which are major biting pests and arbovirus vectors, using drop traps and suction traps baited with four sheep, as bluetongue virus Hosts. Collections were carried out in the field, a largely-open stable and an enclosed stable during six collection periods of 24 hours in April/May, in late June and in September/October 2010 in western France. A total of 986 Culicoides belonging to 13 species, mainly C. brunnicans and C. obsoletus, was collected on animal baits. Culicoides brunnicans was clearly exophagic, whereas C. obsoletus was able to enter stables. Culicoides brunnicans exhibited a bimodal pattern of Host-Seeking activity with peaks just after sunrise and sunset. Culicoides obsoletus was active before sunset in spring and autumn and after sunset in summer, thus illustrating influence of other parameters than light, especially temperature. Description of Host-Seeking behaviors allowed us to discuss control strategies for transmission of Culicoides-borne pathogens, such as bluetongue virus. However, practical vector-control recommendations are difficult to provide because of the variation in the degree of endophagy and time of Host-Seeking activity.
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Host Seeking activity of bluetongue virus vectors endo exophagy and circadian rhythm of culicoides in western europe
PLOS ONE, 2012Co-Authors: Elvina Viennet, Claire Garros, Ignace Rakotoarivony, Xavier Allene, Laëtitia Gardes, Jonathan Lhoir, Ivanna Fuentes, Roger Venail, Didier Crochet, Renaud LancelotAbstract:Feeding success of free-living hematophagous insects depends on their ability to be active when Hosts are available and to reach places where Hosts are accessible. When the hematophagous insect is a vector of pathogens, determining the components of Host-Seeking behavior is of primary interest for the assessment of transmission risk. Our aim was to describe endo/exophagy and circadian Host-Seeking activity of Palaearctic Culicoides species, which are major biting pests and arbovirus vectors, using drop traps and suction traps baited with four sheep, as bluetongue virus Hosts. Collections were carried out in the field, a largely-open stable and an enclosed stable during six collection periods of 24 hours in April/May, in late June and in September/October 2010 in western France. A total of 986 Culicoides belonging to 13 species, mainly C. brunnicans and C. obsoletus, was collected on animal baits. Culicoides brunnicans was clearly exophagic, whereas C. obsoletus was able to enter stables. Culicoides brunnicans exhibited a bimodal pattern of Host-Seeking activity with peaks just after sunrise and sunset. Culicoides obsoletus was active before sunset in spring and autumn and after sunset in summer, thus illustrating influence of other parameters than light, especially temperature. Description of Host-Seeking behaviors allowed us to discuss control strategies for transmission of Culicoides-borne pathogens, such as bluetongue virus. However, practical vector-control recommendations are difficult to provide because of the variation in the degree of endophagy and time of Host-Seeking activity.
Sharon R Hill - One of the best experts on this subject based on the ideXlab platform.
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Mosquito Host Seeking in 3D Using a Versatile Climate-Controlled Wind Tunnel System
Frontiers in behavioral neuroscience, 2021Co-Authors: Annika Hinze, Sharon R Hill, Jörgen Lantz, Rickard IgnellAbstract:Future anthropogenic climate change is predicted to impact sensory-driven behaviours. Building on recent improvements in computational power and tracking technology, we have developed a versatile climate-controlled wind tunnel system, in which to study the effect of climate parameters, including temperature, precipitation, and elevated greenhouse gas levels, on odour-mediated behaviours in insects. To establish a baseline for future studies, we here analysed the Host-Seeking behaviour of the major malaria vector mosquito, Anopheles gambiae sensu strico, to human odour and carbon dioxide (CO2), under tightly controlled climatic conditions, and isolated from potential background contamination by the presence of an experimenter. When presented with a combination of human foot odour and CO2 (case study I), mosquitoes engaged in faster crosswind flight, spent more time in the filamentous odour plume and targeted the odour source more successfully. In contrast, female An. gambiae s. s. presented with different concentrations of CO2 alone, did not display Host-Seeking behaviour (case study II). These observations support previous findings on the role of human Host-associated cues in Host Seeking and confirm the role of CO2 as a synergist, but not a Host-Seeking cue on its own. Future studies are aimed at investigating the effect of climate change on odour-mediated behaviour in mosquitoes and other insects. Moreover, the system will be used to investigate detection and processing of olfactory information in various behavioural contexts, by providing a fine-scale analysis of flight behaviour.
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Dengue infection modulates locomotion and Host Seeking in Aedes aegypti.
PLoS neglected tropical diseases, 2020Co-Authors: Anaïs Karine Tallon, Marcelo G. Lorenzo, Sharon R Hill, Luciano Andrade Moreira, Luis Villegas, Rickard IgnellAbstract:Pathogens may manipulate their human and mosquito Hosts to enhance disease transmission. Dengue, caused by four viral serotypes, is the fastest-growing transmissible disease globally resulting in 50–100 million infections annually. Transmission of the disease relies on the interaction between humans and the vector Aedes aegypti and is largely dependent on the odor-mediated Host Seeking of female mosquitoes. In this study, we use activity monitors to demonstrate that dengue virus-1 affects the locomotion and odor-mediated behavior of Ae. aegypti, reflecting the progression of infection within the mosquito. Mosquitoes 4–6 days post-infection increase locomotion, but do not alter their odor-driven Host-Seeking response. In contrast, females 14–16 days post-infection are less active, yet more sensitive to human odors as assessed by behavioral and electrophysiological assays. Such an increase in physiological and behavioral sensitivity is reflected by the antennal-specific increase in abundance of neural signaling transcripts in 14 days post-infection females, as determined by transcriptome analysis. This suggests that the sensitivity of the mosquito peripheral olfactory system is altered by the dengue virus by enhancing the overall neural responsiveness of the antenna, rather than the selective regulation of chemosensory-related genes. Our study reveals that dengue virus-1 enhances vector-related behaviors in the early stages post-infection that aid in avoiding predation and increasing spatial exploration. On the other hand, at the later stages of infection, the virus enhances the Host-Seeking capacity of the vector, thereby increasing the risk of virus transmission. A potential mechanism is discussed.
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Sex and age modulate antennal chemosensory-related genes linked to the onset of Host Seeking in the yellow-fever mosquito, Aedes aegypti.
Scientific reports, 2019Co-Authors: Anaïs Karine Tallon, Sharon R Hill, Rickard IgnellAbstract:The mosquito Aedes aegypti is the primary vector for the fastest growing infectious disease in the world, dengue fever. Disease transmission heavily relies on the ability of female mosquitoes to locate their human Hosts. Additionally, males may be found in close proximity to humans, where they can find mates. Host Seeking behaviour of both sexes is dependent on adult sexual maturation. Identifying the molecular basis for the onset of Host Seeking may help to determine targets for future vector control. In this study, we investigate modulation of the Host Seeking behaviour and the transcript abundance of the main chemoreceptor families between sexes and across ages in newly-emerged mosquitoes. Attraction to human odour was assessed using a Y-tube olfactometer, demonstrating that both males and females display age-dependent regulation of Host Seeking. The largest increase in transcript abundance was identified for select chemosensory genes in the antennae of young adult Ae. aegypti mosquitoes and reflects the increase in attraction to human odour observed between 1 and 3 day(s) post-emergence in both males and females. Future functional characterisation of the identified differentially abundant genes may provide targets for the development of novel control strategies against vector borne diseases.
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feeding induced changes in allatostatin a and short neuropeptide f in the antennal lobes affect odor mediated Host Seeking in the yellow fever mosquito aedes aegypti
PLOS ONE, 2017Co-Authors: Peter Christ, Anna Reifenrath, Jorg Kahnt, Frank Hauser, Sharon R Hill, Joachim Schachtner, Rickard IgnellAbstract:Aedes aegypti is a model species in which the endogenous regulation of odor-mediated Host Seeking behavior has received some attention. Sugar feeding and Host Seeking in female A. aegypti are transiently inhibited following a blood meal. This inhibition is partially mediated by short neuropeptide F (sNPF). The paired antennal lobes (ALs), as the first processing centers for olfactory information, has been shown to play a significant role in the neuropeptidergic regulation of odor-mediated behaviors in insects. The expression of sNPF, along with other peptides in the ALs of A. aegypti, indicate parallel neuromodulatory systems that may affect olfactory processing. To identify neuropeptides involved in regulating the odor-mediated Host Seeking behavior in A. aegypti, we use a semi-quantitative neuropeptidomic analysis of single ALs to analyze changes in the levels of five individual neuropeptides in response to different feeding regimes. Our results show that the level of sNPF-2, allatostatin-A-5 (AstA-5) and neuropeptide-like precursor-1-5 (NPLP-1-5), but not of tachykinin-related-peptides and SIFamide (SIFa), in the AL of female mosquitoes, changes 24 h and 48 h post-blood meal, and are dependent on prior access to sugar. To assess the role of these neuropeptides in modulating Host Seeking behavior, when systemically injected individually, sNPF-2 and AstA-5 significantly reduced Host Seeking behavior. However, only the injection of the binary mixture of the two neuropeptides lead to a Host Seeking inhibition similar to that observed in blood fed females. We conclude that modulation of the odor mediated Host Seeking behavior of A. aegypti is likely regulated by a dual neuropeptidergic pathway acting in concert in the ALs.
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Chicken volatiles repel Host-Seeking malaria mosquitoes
Malaria journal, 2016Co-Authors: Kassahun T. Jaleta, Habte Tekie, Göran Birgersson, Sharon R Hill, Rickard IgnellAbstract:Anopheles arabiensis is a dominant vector of malaria in sub-Saharan Africa, which feeds indoors and outdoors on human and other vertebrate Hosts, making it a difficult species to control with existing control methods. Novel methods that reduce human-vector interactions are, therefore, required to improve the impact of vector control programmes. Investigating the mechanisms underlying the Host discrimination process in An. arabiensis could provide valuable knowledge leading to the development of novel control technologies. In this study, a Host census and blood meal analysis were conducted to determine the Host selection behaviour of An. arabiensis. Since mosquitoes select and discriminate among Hosts primarily using olfaction, the volatile headspace of the preferred non-human Host and non-Host species, were collected. Using combined gas chromatography and electroantennographic detection analysis followed by combined gas chromatography and mass spectrometry, the bioactive compounds in the headspace collections were identified. The efficiency of the identified non-Host compounds to repel Host-Seeking malaria mosquitoes was tested under field conditions. The Host census and blood meal analyses demonstrated that An. arabiensis strongly prefers human blood when Host Seeking indoors, while it randomly feeds on cattle, goats and sheep when found outdoors. However, An. arabiensis avoids chickens despite their relatively high abundance, indicating that chickens are a non-Host species for this vector. Eleven bioactive compounds were found in the headspace of the non-Host species. Six of these were species-specific, out of which four were identified using combined gas chromatography and mass spectrometry. When tested in the field, the chicken-specific compounds, isobutyl butyrate, naphthalene, hexadecane and trans-limonene oxide, and the generic Host compounds, limonene, cis-limonene oxide and β-myrcene, significantly reduced trap catches within the house compared to a negative control. A significant reduction in trap catch was also observed when suspending a caged chicken next to the trap. Non-Host volatiles repel Host-Seeking An. arabiensis and thus play a significant role in Host discrimination. As such, this study demonstrates that non-Host volatiles can provide protection to humans at risk of mosquito-vectored diseases in combination with established control programmes.
William K. Reisen - One of the best experts on this subject based on the ideXlab platform.
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Landscape affects the Host-Seeking patterns of Culex tarsalis (Diptera: Culicidae) in the Coachella Valley of California.
Journal of medical entomology, 2001Co-Authors: Hugh D. Lothrop, William K. ReisenAbstract:Effective arbovirus transmission requires that the principal vertebrate Hosts and vectors have frequent contact. Vegetation and other landscape features used by roosting or nesting birds at night dictate their exposure to nocturnally active Host-Seeking Culex tarsalis Coquillett and therefore to western equine encephalomyelitis and St. Louis encephalitis viruses. Precipitin tests on 645 Cx. tarsalis that were collected resting and Host-Seeking near the Salton Sea in Coachella Valley, CA, indicated that passeriform birds (64%) and rabbits (25%) were the most frequent bloodmeal Hosts and that the percentage of females feeding on birds varied temporally as an inverse function of mosquito abundance. Blood meals were not taken from communally roosting water birds. The spatial distribution of Host-Seeking females then was investigated by deploying dry ice baited traps within seven sites representative of habitats found along the Salton Sea. Mosquito catch was greatest at traps within elevated vegetation such as Tamarisk, mesquite, cattails, and orchards and lowest at traps positioned at snags over water, sand bars, open fields, and within housing in a small rural community. These data indicate that Host-Seeking Cx. tarsalis females congregated at specific landscape features that were not necessarily associated with large concentrations of potential bloodmeal Hosts.
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Time of Host-Seeking by Culex tarsalis (Diptera:Culicidae) in California.
Journal of medical entomology, 1997Co-Authors: William K. Reisen, Hugh D. Lothrop, R. P. MeyerAbstract:Factors altering the pattern of Culex tarsalis Coquillett Host-Seeking activity were studied in Kern and Riverside counties of California using an automatic time-segregated sampler baited with bottled CO2 gas released at 0.5 or 1.0 liters/min. Host-Seeking always commenced shortly after sunset and usually peaked during the succeeding 1-3 h, the hottest and driest time of the night. The time of maximal activity varied over time and space, because of increased mosquito abundance (presumably reduced blood feeding success), distance of the sampler from resting sites, adulticide applications, and perhaps weather.
Elvina Viennet - One of the best experts on this subject based on the ideXlab platform.
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Host-Seeking activity of bluetongue virus vectors: endo/exophagy and circadian rhythm of Culicoides in Western Europe.
PloS one, 2012Co-Authors: Elvina Viennet, Claire Garros, Ignace Rakotoarivony, Xavier Allene, Laëtitia Gardes, Jonathan Lhoir, Ivanna Fuentes, Roger Venail, Didier Crochet, Renaud LancelotAbstract:Feeding success of free-living hematophagous insects depends on their ability to be active when Hosts are available and to reach places where Hosts are accessible. When the hematophagous insect is a vector of pathogens, determining the components of Host-Seeking behavior is of primary interest for the assessment of transmission risk. Our aim was to describe endo/exophagy and circadian Host-Seeking activity of Palaearctic Culicoides species, which are major biting pests and arbovirus vectors, using drop traps and suction traps baited with four sheep, as bluetongue virus Hosts. Collections were carried out in the field, a largely-open stable and an enclosed stable during six collection periods of 24 hours in April/May, in late June and in September/October 2010 in western France. A total of 986 Culicoides belonging to 13 species, mainly C. brunnicans and C. obsoletus, was collected on animal baits. Culicoides brunnicans was clearly exophagic, whereas C. obsoletus was able to enter stables. Culicoides brunnicans exhibited a bimodal pattern of Host-Seeking activity with peaks just after sunrise and sunset. Culicoides obsoletus was active before sunset in spring and autumn and after sunset in summer, thus illustrating influence of other parameters than light, especially temperature. Description of Host-Seeking behaviors allowed us to discuss control strategies for transmission of Culicoides-borne pathogens, such as bluetongue virus. However, practical vector-control recommendations are difficult to provide because of the variation in the degree of endophagy and time of Host-Seeking activity.
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Host Seeking activity of bluetongue virus vectors endo exophagy and circadian rhythm of culicoides in western europe
PLOS ONE, 2012Co-Authors: Elvina Viennet, Claire Garros, Ignace Rakotoarivony, Xavier Allene, Laëtitia Gardes, Jonathan Lhoir, Ivanna Fuentes, Roger Venail, Didier Crochet, Renaud LancelotAbstract:Feeding success of free-living hematophagous insects depends on their ability to be active when Hosts are available and to reach places where Hosts are accessible. When the hematophagous insect is a vector of pathogens, determining the components of Host-Seeking behavior is of primary interest for the assessment of transmission risk. Our aim was to describe endo/exophagy and circadian Host-Seeking activity of Palaearctic Culicoides species, which are major biting pests and arbovirus vectors, using drop traps and suction traps baited with four sheep, as bluetongue virus Hosts. Collections were carried out in the field, a largely-open stable and an enclosed stable during six collection periods of 24 hours in April/May, in late June and in September/October 2010 in western France. A total of 986 Culicoides belonging to 13 species, mainly C. brunnicans and C. obsoletus, was collected on animal baits. Culicoides brunnicans was clearly exophagic, whereas C. obsoletus was able to enter stables. Culicoides brunnicans exhibited a bimodal pattern of Host-Seeking activity with peaks just after sunrise and sunset. Culicoides obsoletus was active before sunset in spring and autumn and after sunset in summer, thus illustrating influence of other parameters than light, especially temperature. Description of Host-Seeking behaviors allowed us to discuss control strategies for transmission of Culicoides-borne pathogens, such as bluetongue virus. However, practical vector-control recommendations are difficult to provide because of the variation in the degree of endophagy and time of Host-Seeking activity.