scholarly journals Insect Repellents Mediate Species-Specific Olfactory Behaviors in Mosquitoes

2020 ◽  
Author(s):  
Ali Afify ◽  
Christopher John Potter
Keyword(s):  
Mosquito Species ◽  
Behavioral Responses ◽  
Anopheles Coluzzii ◽  
Olfactory Neurons ◽  
Insect Repellents ◽  
Olfactory Responses ◽  
Behavioral Studies ◽  
Lemongrass Oil ◽  
Mosquito Repellents ◽  
Species Specific

Abstract Background: The species-specific mode of action for DEET and many other mosquito repellents is often unclear. Confusion may arise for many reasons. First, the response of a single mosquito species is often used to represent all mosquito species. Second, behavioral studies usually test the effect of repellents on mosquito attraction towards human odorants, rather than their direct repulsive effect on mosquitoes. Third, the mosquito sensory neuron responses towards repellents are often not directly examined. Methods: Here, we used a close proximity response assay to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii , Aedes aegypti , and Culex quinquefasciatus mosquitoes. Additionally, we used this behavioral assay and calcium imaging recordings of antennae to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET. Results: We found that An. coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. Quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, we found that high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antenna than lower concentrations. Finally, we found that changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviors. Conclusions: Our findings suggest that different species of mosquitoes have different behavioral responses to repellents. We further suggest that high-odor concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioral responses. Finally, we show that DEET can decrease the neuronal and behavioral response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency.

scholarly journals Insect Repellents Mediate Species-Specific Olfactory Behaviors in Mosquitoes

2020 ◽  
Author(s):  
Ali Afify ◽  
Christopher John Potter
Keyword(s):  
Mosquito Species ◽  
Behavioral Responses ◽  
Anopheles Coluzzii ◽  
Olfactory Neurons ◽  
Insect Repellents ◽  
Olfactory Responses ◽  
Behavioral Studies ◽  
Lemongrass Oil ◽  
Mosquito Repellents ◽  
Species Specific

Abstract Background: The species-specific mode of action for DEET and many other mosquito repellents is often unclear. Confusion may arise for many reasons. First, the response of a single mosquito species is often used to represent all mosquito species. Second, behavioral studies usually test the effect of repellents on mosquito attraction towards human odorants, rather than their direct repulsive effect on mosquitoes. Third, the mosquito sensory neuron responses towards repellents are often not directly examined.Methods: Here, we used a close proximity response assay to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii, Aedes aegypti, and Culex quinquefasciatus mosquitoes. Additionally, we used this behavioral assay and calcium imaging recordings of antennae to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET.Results: We found that An. coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. Quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, we found that high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antenna than lower concentrations. Finally, we found that changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviors.Conclusions: Our findings suggest that different species of mosquitoes have different behavioral responses to repellents. We further suggest that high-odor concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioral responses. Finally, we show that DEET can decrease the neuronal and behavioral response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency.

Insect Repellents Mediate Species-Specific Olfactory Behaviours in Mosquitoes

2020 ◽  
Author(s):  
Ali Afify ◽  
Christopher John Potter
Keyword(s):  
Mosquito Species ◽  
Anopheles Coluzzii ◽  
Olfactory Neurons ◽  
Olfactory Responses ◽  
Close Proximity ◽  
Lemongrass Oil ◽  
Mosquito Repellents ◽  
Receptor Neurons ◽  
High Concentrations ◽  
Species Specific

Abstract Background The species-specific mode of action for DEET and many other mosquito repellents is often unclear. Confusion may arise for many reasons. First, the response of a single mosquito species is often used to represent all mosquito species. Second, behavioural studies usually test the effect of repellents on mosquito attraction towards human odorants, rather than their direct repulsive effect on mosquitoes. Third, the mosquito sensory neuron responses towards repellents are often not directly examined. Methods A close proximity response assay was used to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii, Aedes aegypti and Culex quinquefasciatus mosquitoes. Additionally, behavioural assay and calcium imaging recordings of antennae were used to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET. Results An. coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antennae than lower concentrations. Finally, changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviours. Conclusions The findings described here suggest that different species of mosquitoes have different behavioural responses to repellents. The data further suggest that high-odour concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioural responses. Finally, DEET can decrease the neuronal and behavioural response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency. Methods: Here, we used a close proximity response assay to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii , Aedes aegypti , and Culex quinquefasciatus mosquitoes. Additionally, we used this behavioral assay and calcium imaging recordings of antennae to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET. Results: We found that An. coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. Quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, we found that high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antenna than lower concentrations. Finally, we found that changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviors. Conclusions: Our findings suggest that different species of mosquitoes have different behavioral responses to repellents. We further suggest that high-odor concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioral responses. Finally, we show that DEET can decrease the neuronal and behavioral response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency.

scholarly journals Circadian regulation of light-evoked attraction/avoidance in day- vs. night-biting mosquitoes

2019 ◽  
Author(s):  
Lisa Soyeon Baik ◽  
Ceazar Nave ◽  
David D. Au ◽  
Tom Guda ◽  
Joshua A. Chevez ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Mosquito Species ◽  
Behavioral Responses ◽  
Time Of Day ◽  
Disease Vectors ◽  
Anopheles Coluzzii ◽  
Long Wavelength ◽  
Species Specific ◽  
Wavelength Light ◽  
Specific Control

AbstractMosquitoes pose widespread threats to humans and other animals as disease vectors. Day- vs. night-biting mosquitoes occupy distinct time-of-day niches and exhibit very different innate temporal attraction/avoidance behavioral responses to light, yet little is known about their circuit or molecular mechanisms. Day-biting diurnal mosquitoes Aedes aegypti are attracted to light during the day regardless of spectra. In contrast, night-biting nocturnal mosquitoes Anopheles coluzzii avoid short, but not long wavelength light. Attraction/avoidance behavioral responses to light in both species change with time-of-day and show distinct sex and circuit differences. The basis of diurnal versus nocturnal behavior is driven by clock timing, which cycle anti-phase between day-biting versus night-biting mosquito species. Disruption of the circadian molecular clock severely interferes with light-evoked attraction/avoidance behavior in mosquitoes. In summary, attraction/avoidance mosquito behaviors are circadian and light regulated, which may be applied towards species specific control of harmful mosquitoes.

scholarly journals Molecular basis of fatty acid taste in Drosophila

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ji-Eun Ahn ◽  
Yan Chen ◽  
Hubert Amrein
Keyword(s):  
Fatty Acids ◽  
Behavioral Responses ◽  
Hexanoic Acid ◽  
Wild Type ◽  
Cell Type ◽  
Ionotropic Receptor ◽  
Behavioral Studies ◽  
Cell Type Specific ◽  
Receptor Neurons ◽  
Ir Genes

Behavioral studies have established that Drosophila appetitive taste responses towards fatty acids are mediated by sweet sensing Gustatory Receptor Neurons (GRNs). Here we show that sweet GRN activation requires the function of the Ionotropic Receptor genes IR25a, IR76b and IR56d. The former two IR genes are expressed in several neurons per sensillum, while IR56d expression is restricted to sweet GRNs. Importantly, loss of appetitive behavioral responses to fatty acids in IR25a and IR76b mutant flies can be completely rescued by expression of respective transgenes in sweet GRNs. Interestingly, appetitive behavioral responses of wild type flies to hexanoic acid reach a plateau at ~1%, but decrease with higher concentration, a property mediated through IR25a/IR76b independent activation of bitter GRNs. With our previous report on sour taste, our studies suggest that IR-based receptors mediate different taste qualities through cell-type specific IR subunits.

Parabrachial Neural Coding of Taste Stimuli in Awake Rats

1997 ◽  
Vol 78 (5) ◽  
pp. 2254-2268 ◽  
Author(s):  
Hisao Nishijo ◽  
Ralph Norgren
Keyword(s):  
Citric Acid ◽  
Neural Coding ◽  
Simulation Analysis ◽  
Neuronal Response ◽  
Behavioral Responses ◽  
Hierarchical Cluster ◽  
Neural Data ◽  
Behavioral Studies ◽  
Single Cluster ◽  
Awake Rats

Nishijo, Hisao and Ralph Norgren. Parabrachial neural coding of taste stimuli in awake rats. J. Neurophysiol. 78: 2254–2268, 1997. In awake, behaving rats, the activity of 74 single neurons in the pontine parabrachial nucleus (PBN) was recorded in response to sapid stimulation by 15 chemicals. Of these, 44 taste cells were tested with all 15 stimuli. Based on their responsiveness to 4 standard stimuli, these neurons were categorized as follows: 23 NaCl-best, 15 sucrose-best, 5 citric acid–best, and 1 quinine HCl-best. Several forms of multivariate analyses indicated that the taste responses matched both the behavioral responses to and, less well, the chemical structure of, the sapid stimuli. A hierarchical cluster analysis of the neurons substantially confirmed the best-stimulus categorization, but separated the NaCl-best cells into those that responded more to Na+-containing salts and those that responded more to Cl−-containing salts. The cells that responded best to the Na+ moiety actually were somewhat more correlated with the sucrose-best cells than with those that responded to the Cl−-containing stimuli. Citric acid–best neurons and the lone quinine-best unit formed a single cluster of neurons that responded well to acids, as well as to NH4Cl and, to a lesser extent, NaNO3. A factor analysis of the neuronal response profiles revealed that three factors accounted for 78.8% of the variance in the sample. Similar analyses of the stimuli suggested that PBN neurons respond to four or five sets of stimuli related by their chemical makeup or by human psychophysical reports. The capacity of rats to make these discriminations has been documented by other behavioral studies in which rodents generalize across sapid chemicals within each of 5 stimulus categories. Furthermore, a simulation analysis of the neural data replicated behavioral results that used amiloride, a Na+ channel blocker, in which rats generalized NaCl to non-Na+, Cl− salts. Thus, using a variety of analyses, in awake rats, the activity of PBN taste neurons tracks their behavioral responses to a variety of chemical stimuli.

scholarly journals In Silico Karyotyping of Chromosomally Polymorphic Malaria Mosquitoes in the Anopheles gambiae Complex

2019 ◽  
Vol 9 (10) ◽  
pp. 3249-3262 ◽  
Author(s):  
R. Rebecca Love ◽  
Seth N. Redmond ◽  
Marco Pombi ◽  
Beniamino Caputo ◽  
Vincenzo Petrarca ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
In Silico ◽  
Mosquito Species ◽  
Chromosomal Rearrangements ◽  
Small Subset ◽  
Anopheles Coluzzii ◽  
Strongly Correlated ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Malaria Mosquitoes

Chromosomal inversion polymorphisms play an important role in adaptation to environmental heterogeneities. For mosquito species in the Anopheles gambiae complex that are significant vectors of human malaria, paracentric inversion polymorphisms are abundant and are associated with ecologically and epidemiologically important phenotypes. Improved understanding of these traits relies on determining mosquito karyotype, which currently depends upon laborious cytogenetic methods whose application is limited both by the requirement for specialized expertise and for properly preserved adult females at specific gonotrophic stages. To overcome this limitation, we developed sets of tag single nucleotide polymorphisms (SNPs) inside inversions whose biallelic genotype is strongly correlated with inversion genotype. We leveraged 1,347 fully sequenced An. gambiae and Anopheles coluzzii genomes in the Ag1000G database of natural variation. Beginning with principal components analysis (PCA) of population samples, applied to windows of the genome containing individual chromosomal rearrangements, we classified samples into three inversion genotypes, distinguishing homozygous inverted and homozygous uninverted groups by inclusion of the small subset of specimens in Ag1000G that are associated with cytogenetic metadata. We then assessed the correlation between candidate tag SNP genotypes and PCA-based inversion genotypes in our training sets, selecting those candidates with >80% agreement. Our initial tests both in held-back validation samples from Ag1000G and in data independent of Ag1000G suggest that when used for in silico inversion genotyping of sequenced mosquitoes, these tags perform better than traditional cytogenetics, even for specimens where only a small subset of the tag SNPs can be successfully ascertained.

scholarly journals Toxicity of a plant based mosquito repellent/killer

2012 ◽  
Vol 5 (4) ◽  
pp. 184-191 ◽  
Author(s):  
Bhoopendra Singh ◽  
Prakash Raj Singh ◽  
Manoj Kumar Mohanty
Keyword(s):  
Mosquito Species ◽  
Scientific Information ◽  
Herbal Product ◽  
Single Mode ◽  
Systemic Review ◽  
Mosquito Repellent ◽  
Medicinal Uses ◽  
Medline Search ◽  
Insect Repellents ◽  
Mosquito Behaviour

ABSTRACT The mission to make humans less attractive to mosquitoes has fuelled decades of scientific research on mosquito behaviour and control. The search for the perfect topical insect repellent/killer continues. This analysis was conducted to review and explore the scientific information on toxicity produced by the ingredients/contents of a herbal product. In this process of systemic review the following methodology was applied. By doing a MEDLINE search with key words of selected plants, plant based insect repellents/ killers pertinent articles published in journals and authentic books were reviewed. The World Wide Web and the Extension Toxicity Network database (IPCS-ITOX) were also searched for toxicology data and other pertinent information. Repellents do not all share a single mode of action and surprisingly little is known about how repellents act on their target insects. Moreover, different mosquito species may react differently to the same repellent. After analysis of available data and information on the ingredient, of the product in relation to medicinal uses, acute and chronic toxicity of the selected medicinal plants, it can be concluded that the ingredients included in the herbal product can be used as active agents against mosquitoes. If the product which contains the powder of the above said plants is applied with care and safety, it is suitable fo use as a mosquito repellent/killer.

scholarly journals 13-Tetradecenyl acetate, a female-produced sex pheromone component of the economically important click beetle Melanotus communis (Gyllenhal) (Coleoptera: Elateridae)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Livy Williams ◽  
Jacqueline M. Serrano ◽  
Paul J. Johnson ◽  
Jocelyn G. Millar
Keyword(s):  
Sex Attractant ◽  
Insect Pests ◽  
Management Strategies ◽  
Behavioral Studies ◽  
Click Beetle ◽  
Tetradecenyl Acetate ◽  
Plastic Bag ◽  
Single Compound ◽  
Species Specific ◽  
Dose Dependent

Abstract Species-specific behavior-modifying chemicals have been used for more than 50 years for monitoring and management of insect pests of agriculture and human health. Elaterid beetle larvae are among insect pests in soil that are increasingly problematic, in part due to the lack of effective management strategies. However, little is known about the insect-produced chemicals that mediate the reproductive behavior of these pests. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adults of Melanotus communis, commonly called the corn wireworm, the larvae of which are economically important pests of U.S. crops. Our results indicated that a single female-produced chemical, 13-tetradecenyl acetate, was strongly attractive to conspecific male beetles, and did not appear to attract other species. In field evaluations, male M. communis exhibited a dose-dependent response to this compound. In a trial comparing different slow-release dispensers, a small rubber septum impregnated with the chemical was as effective as and easier to use than a plastic bag dispenser. Given that the sex attractant of this insect consists of a single compound that can be readily synthesized, its development for monitoring and management of the corn wireworm may be economically feasible.

Acute olfactory sensitivity to prostaglandins but not to gonadal steroids in two sympatric species of Catostomus (Pisces: Cypriniformes)

1992 ◽  
Vol 70 (10) ◽  
pp. 1897-1903 ◽  
Author(s):  
J. R. Cardwell ◽  
J. G. Dulka ◽  
N. E. Stacey
Keyword(s):  
Sympatric Species ◽  
Preliminary Evidence ◽  
Gonadal Steroids ◽  
Electrophysiological Recording ◽  
Olfactory Sensitivity ◽  
Complex Issue ◽  
Olfactory Responses ◽  
Prostaglandin F ◽  
Species Specific ◽  
Longnose Sucker

The discovery that released hormones (steroids and prostaglandins) and their metabolites function as potent pheromones in some fishes provides an opportunity to determine whether these chemically identified pheromones are species specific. As a first step in studying this complex issue, we used an extracellular electrophysiological recording technique (electro-olfactogram) to investigate the olfactory sensitivity of two sympatrically spawning catostomid species (white sucker, Catostomus commersoni, and longnose sucker, Catostomus catostomus; Cypriniformes: Catostomidae) to steroids and prostaglandins that might function as sex pheromones. Both species were acutely sensitive to F-series prostaglandins, particularly prostaglandin-F2α and its metabolite 15-ketoprostaglandin-F2α, but exhibited no olfactory responses to free or conjugated gonadal steroids. The data from tests of olfactory sensitivity to a range of gonadal steroids, though negative, provide preliminary evidence that maturational steroid hormones do not function as pheromones in catostomids as they do in other cypriniform fishes. We were unable to detect species differences in receptor-level olfactory sensitivity to hormones or hormone metabolites, although we cannot discount possible differences at other levels of the olfactory system.

scholarly journals Mosquito repellents in frog skin

2006 ◽  
Vol 2 (2) ◽  
pp. 242-245 ◽  
Author(s):  
C.R Williams ◽  
B.P.C Smith ◽  
S.M Best ◽  
M.J Tyler
Keyword(s):  
Frog Skin ◽  
Volatile Components ◽  
Insect Repellents ◽  
Host Seeking ◽  
Culex Annulirostris ◽  
Litoria Caerulea ◽  
Frog Species ◽  
Mosquito Repellents ◽  
Skin Secretions ◽  
Ectoparasite Infestation

The search for novel insect repellents has been driven by health concerns over established synthetic compounds such as diethyl- m -toluamide (DEET). Given the diversity of compounds known from frog skin and records of mosquito bite and ectoparasite infestation, the presence of mosquito repellents in frogs seemed plausible. We investigated frog skin secretions to confirm the existence of mosquito repellent properties. Litoria caerulea secretions were assessed for mosquito repellency by topical application on mice. The secretions provided protection against host-seeking Culex annulirostris mosquitoes. Olfactometer tests using aqueous washes of skin secretions from L. caerulea and four other frog species were conducted to determine whether volatile components were responsible for repellency. Volatiles from Litoria rubella and Uperoleia mjobergi secretions were repellent to C. annulirostris , albeit not as repellent as a DEET control. The demonstration of endogenous insect repellents in amphibians is novel, and demonstrates that many aspects of frog chemical ecology remain unexplored.

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