Adaptation of the repellency response to DEET in Rhodnius prolixus

Sfara, Valeria; Mougabure‐Cueto, Gastón; Zerba, Eduardo; Alzogaray, Raúl A.

doi:10.1016/j.jinsphys.2011.07.009

Cited by 32 publications

(30 citation statements)

References 29 publications

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“…Overall, the increased response to a second treatment with DEET on an attractive stimulus, after pre-exposure to DEET with no attractant present, indicates that the learned behaviour is not by association with an attractant as was found in other studies with host-seeking insects [11], [18], [33]. It is instead a direct response to a single exposure to the DEET, Such habituation to DEET has been shown in R. prolixus , where continuous stimulation led to 10–20 minutes of reduced repellency [9]. Thus it seems likely that in our experiments increased DEET-insensitivity results from sensory adaptation or habituation, whereby there is an decrease in response to a stimulus (in this case, DEET) after repeated exposure [34], [35].…”

Section: Discussionsupporting

confidence: 62%

“…For example, a small proportion of individuals in populations of Aedes aegypti mosquitoes and Drosophila melanogaster fruit flies will move towards an attractant despite the presence of DEET, a genetic “insensitivity” which can be selected for in the population [5]–[8], and which corresponds to changes in the function of the peripheral olfactory system [8]. However, in a recent study, the triatomine bug, Rhodnius prolixus , showed a decrease in behavioural repellency after continuous stimulation with DEET [9], indicating that other, non-genetic, factors may play a role in preventing insects from responding to DEET.…”

Section: Introductionmentioning

confidence: 99%

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Aedes aegypti Mosquitoes Exhibit Decreased Repellency by DEET following Previous Exposure

et al. 2013

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DEET (N,N-Diethyl-m-toluamide) is one of the most widely used mosquito repellents. Although DEET has been shown to be extremely effective, recent studies have revealed that certain individual insects are unaffected by its presence. A genetic basis for this has been shown in Aedes aegypti mosquitoes and the fruit fly Drosophila melanogaster, but, for the triatomine bug, Rhodnius prolixus, a decrease in response to DEET occurred shortly after previous exposure, indicating that non-genetic factors may also be involved in DEET “insensitivity”. In this study, we examined host-seeking behaviour and electrophysiological responses of A. aegypti after pre-exposure to DEET. We found that three hours after pre-exposure the mosquitoes showed behavioural insensitivity, and electroantennography revealed this correlated with the olfactory receptor neurons responding less to DEET. The change in behaviour as a result of pre-exposure to DEET has implications for the use of repellents and the ability of mosquitoes to overcome them.

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Section: Discussionsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Aedes aegypti Mosquitoes Exhibit Decreased Repellency by DEET following Previous Exposure

et al. 2013

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“…The efficiency of DEET, the most commonly employed insect repellent (Fradin, 1998), relies on its ability to either 'jam' an insect's olfactory perception (Bohbot and Dickens, 2010;Pellegrino et al, 2011) or trigger aversive behavioural responses (Syed and Leal, 2008;Liu et al, 2010). Its efficiency in repelling mosquitoes was recently shown to be reduced in A. aegypti and Rhodnius prolixus shortly after previous exposure (Sfara et al, 2011;Stanczyk et al, 2013). If non-associative phenomena can impair DEET efficacy, it seems legitimate to wonder whether mosquitoes' abilities to perform associative learning could also interfere with DEET efficiency.…”

Section: Research Articlementioning

confidence: 99%

Olfactory learning and memory in the disease vector mosquito,Aedes aegypti

Vinauger

Lutz

Riffell

2014

Journal of Experimental Biology

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Olfactory learning in blood-feeding insects, such as mosquitoes, could play an important role in host preference and disease transmission. However, standardised protocols allowing testing of their learning abilities are currently lacking, and how different olfactory stimuli are learned by these insects remains unknown. Using a Pavlovian conditioning paradigm, we trained individuals and groups of Aedes aegypti mosquitoes to associate an odorant conditioned stimulus (CS) with a blood-reinforced thermal stimulus (unconditioned stimulus; US). Results showed, first, that mosquitoes could learn the association between L-lactic acid and the US, and retained the association for at least 24 h. Second, the success of olfactory conditioning was dependent upon the CS -some odorants that elicited indifferent responses in naïve mosquitoes, such as L-lactic acid and 1-octen-3-ol, were readily learned, whereas others went from aversive to attractive after training (Z-3-hexen-1-ol) or were untrainable (β-myrcene and benzyl alcohol). Third, we examined whether mosquitoes' ability to learn could interfere with the action of the insect repellent DEET. Results demonstrated that pre-exposure and the presence of DEET in the CS reduced the aversive effects of DEET. Last, the nature of the formed memories was explored. Experiments using cold-shock treatments within the first 6 h posttraining (for testing anaesthesia-resistant memory) and a protein synthesis inhibitor (cycloheximide; to disrupt the formation of longterm memory) both affected mosquitoes' performances. Together, these results show that learning is a crucial component in odour responses in A. aegypti, and provide the first evidence for the functional role of different memory traces in these responses.

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“…Concerning triatomine vectors of Chagas disease, different aspects of their response to DEET have been analysed in detail, as for example the spatial distribution and olfactory orientation of Triatoma infestans (Alzogaray et al, 2000), the effect of nitric oxide on repellency induced by DEET in Rhodnius prolixus (Sfara et al, 2008) and the loss of sensitivity to DEET following preexposition in the same species (Sfara et al, 2011). Some other relevant aspects, such as the exact way in which it modulates the behaviour of bugs or its relative efficacy as compared to other compounds, remain however unknown.…”

Section: Introductionmentioning

confidence: 99%