scholarly journals The oviposition cue indole inhibits animal-host attraction in Aedes aegypti mosquitoes

2021 ◽  
Author(s):  
Amir Dekel ◽  
Evyatar Sar-Shalom ◽  
Esther Yakir ◽  
Jonathan Daniel Bohbot
Keyword(s):  
Aedes Aegypti ◽  
Long Range ◽  
Disease Transmission ◽  
Odorant Receptor ◽  
Host Attraction ◽  
Animal Host ◽  
Insect Repellents ◽  
Host Seeking ◽  
Spatial Repellent ◽  
Seeking Behavior

Abstract Mosquitoes represent a major source of disease transmission and possess the uncanny ability to locate suitable animal-hosts, a feature mediated by their exquisite olfactory system. Insect repellents such as N,N-Diethyl-meta-toluamide, also called DEET, have been shown to activate and inhibit mosquito odorant receptors resulting in behavioral modulation. This and other repellents available for personal protection against mosquitoes are topically applied on the skin and operate at short range. In our search for potential long-range odorant repellents, we have hypothesized that the shared chemical similarities between indole and DEET, may confer the former the ability to block odorant receptor function and inhibit human-host attraction. Using the two-electrode voltage clamp of Xenopus laevis oocytes as a pharmacological platform, we provide evidence that indole inhibits the Aedes aegypti (R)-1-octen-3-ol receptor OR8, a receptor involved in the decision of female mosquitoes to identify human hosts. Coincidentally, we also show that indole inhibits the animal-host seeking behavior of female Aedes aegypti. Together, our findings suggests that indole may be a candidate spatial repellent for the long-range protection of humans against mosquito bites.

scholarly journals Novel small molecule agonists of an Aedes aegypti neuropeptide Y receptor block mosquito biting behavior

2018 ◽  
Author(s):  
Laura B. Duvall ◽  
Lavoisier Ramos-Espiritu ◽  
Kyrollos E. Barsoum ◽  
J. Fraser Glickman ◽  
Leslie B. Vosshall
Keyword(s):  
Aedes Aegypti ◽  
Neuropeptide Y ◽  
Small Molecule ◽  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Behavioral Suppression ◽  
Host Seeking ◽  
Novel Approach ◽  
Seeking Behavior

AbstractFemale Aedes aegypti mosquitoes bite humans to obtain a blood-meal to develop their eggs. Remarkably, strong attraction to humans is suppressed for several days after the blood-meal by an unknown mechanism. We investigated a role for neuropeptide Y (NPY)-related signaling in this long-term behavioral suppression, and discovered that drugs targeting human NPY receptors modulate mosquito host-seeking behavior. In a screen of all 49 predicted Ae. aegypti peptide receptors, we identified NPY-like receptor 7 (NPYLR7) as the sole target of these human drugs. To obtain small molecule agonists selective for NPYLR7, we carried out a high-throughput cell-based assay of 265,211 compounds, and isolated 6 highly selective NPYLR7 agonists that inhibit mosquito attraction to humans. NPYLR7 CRISPR-Cas9 null mutants are defective in behavioral suppression, and resistant to these drugs. Finally, we show that these drugs are capable of inhibiting biting and blood-feeding on a live host, suggesting a novel approach to control infectious disease transmission by controlling mosquito behavior.

Detection of Fluorescent Powders and Their Effect on Survival and Recapture of Aedes aegypti (Diptera: Culicidae)

2019 ◽  
Vol 57 (1) ◽  
pp. 266-272 ◽  
Author(s):  
Diana Rojas-Araya ◽  
Barry W Alto ◽  
Nathan Burkett-Cadena ◽  
Derek At Cummings
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Adult Survival ◽  
Mosquito Vector ◽  
Host Seeking ◽  
Baited Traps ◽  
Impact On Survival ◽  
Invasive Mosquito ◽  
Risk Of Disease ◽  
Potential Impact

Abstract The use of insect markers, such as fluorescent powders, is a useful tool for studying ecological and epidemiological questions. Evaluating their effect on vectors of human disease agents, such as the invasive mosquito vector Aedes aegypti (Linnaeus), is crucial for their practical and reliable use, especially in parameters linked to the risk of disease transmission such as adult survival, dispersal, and host-seeking. Seven fluorescent powders (Hercules Radiant, DayGlo (DG), Risk Reactor (RR), and Angstrom Technologies), applied externally on cohorts of Ae. aegypti female mosquitoes, were tested to determine their impact on survival and recapture by baited mosquito traps, and their detectability after being exposed to controlled laboratory and semifield environments. There were no significant differences in survival among marked and unmarked females across all powders. Marked females were significantly less likely to be captured in baited traps relative to unmarked females, except for one of the DG powders. All females remained visibly marked on five parts of their body for 30 d (under both environments), except for one of the RR powders. The tested powders and application method are suitable for tracking mosquitoes throughout most of their lives under different environments, without significantly affecting their survival, but with potential impact on recapture by baited traps, possibly due to effects on senses or other physiological traits.

scholarly journals Questing by Tick Larvae (Acari: Ixodidae): A Review of the Influences That Affect Off-Host Survival

2020 ◽  
Author(s):  
Brenda Leal ◽  
Emily Zamora ◽  
Austin Fuentes ◽  
Donald B Thomas ◽  
Robert K Dearth
Keyword(s):  
Larval Stage ◽  
Disease Transmission ◽  
Abiotic Factors ◽  
Ixodid Ticks ◽  
Physiological Factors ◽  
Important Species ◽  
Limiting Behavior ◽  
Terrestrial Vertebrates ◽  
Host Seeking ◽  
Seeking Behavior

Abstract Questing is a host-seeking behavior in which ticks ascend plants, extend their front legs, and wait poised for a chance to attach to a passing host. Hard ticks are ectoparasites of terrestrial vertebrates and because some species vector disease, they are among the most medically important of arthropod pests. All ixodid ticks require blood to survive and reproduce with the number of blood-hosts needed to complete their life cycle varying among species. The vast majority are three-host ticks requiring a different host for each developmental stage: larva, nymph, and adult. A few, including some of the most economically important species, are one-host ticks, that quest only in the larval stage. Questing is a rate-limiting behavior critical to tick survival and disease transmission. For the off-host larval stage, survival is highly dependent on ecological and physiological factors. Yet, off-host larval ecophysiology is often overlooked for the more obvious adult and nymphal tick-host interactions. This review summarizes the literature on ixodid larval questing with emphasis on how specific biotic and abiotic factors affect off-host survival.

scholarly journals Changes in Host-Seeking Behavior of Puerto Rican Aedes aegypti After Colonization

2011 ◽  
Vol 48 (3) ◽  
pp. 533-537 ◽  
Author(s):  
Gary G. Clark ◽  
Ulrich R. Bernier ◽  
Sandra A. Allan ◽  
Daniel L. Kline ◽  
Frances V. Golden
Keyword(s):  
Aedes Aegypti ◽  
Puerto Rican ◽  
Host Seeking ◽  
Seeking Behavior

scholarly journals Impact of visual features on capture of Aedes aegypti with host decoy traps (HDT)

2020 ◽  
Author(s):  
Joseph Y. Tang ◽  
Jackline Kosgei ◽  
Eric Ochomo ◽  
Bryson A. Ndenga ◽  
Roya Ghiaseddin ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Visual Information ◽  
Effective Means ◽  
Capture Rate ◽  
Mosquito Vector ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Olfactory Stimuli ◽  
Black Surface ◽  
Visual Properties

Abstract BackgroundAedes aegypti is the major mosquito vector of many burdensome human diseases. While behavioral research has focused primarily on understanding the importance of olfactory stimuli in its host-seeking abilities, Ae. aegypti’s vision has also been shown to contribute significantly to locating a human host. In this semi-field study conducted in Kisian, Kisumu County, Kenya, we explored the role of visual properties in Aedes host-seeking by testing four different visual characteristics presented in host decoy traps (HDT). This surveillance trap presents a combination of visual, thermal, and odor stimuli to attract bloodmeal-seeking mosquitoes. This was also the first test of HDT for sampling Aedes mosquitoes, having previously been shown to be effective for capture of other vector genera such as Anopheles, Mansonia, and Culex in field settings.ResultsOur results show that the HDT is an effective means of capturing Ae. aegypti mosquitoes, with a per trial capture rate of up to 69% across four visually distinct HDTs deployed simultaneously in a semi-field arena. Of these four, a solid black HDT (HDT B) captured more mosquitoes than HDTs with: black-white stripes (HDT S), black-white checkerboard patches (HDT P), and a solid white color (HDT W). Across 16 replicates wherein 200 mosquitoes were released per trial, HDT B caught more mosquitoes than HDTs S, P, and W by a factor of 1.9, 1.7, and 1.5 respectively. In all cases, mosquito capture was not evenly distributed on the HDT surface, with captures on the HDT’s outer half, away from the odor delivery, exceeding captures on the inner half facing towards the odor delivery by a factor of 4.8, 3.7, 3.7, and 5.1 on HDTs B, S, P, and W respectively.Conclusions: Our results establish that in semi-field conditions, the HDT is effective for the capture of Ae. aegypti mosquitoes and provides a flexible platform to test experimental parameters pertinent to the host-seeking behavior of mosquito vector species. We show that Ae. aegypti makes use of dark, but not light, high contrast visual information while responding to both the olfactory and thermal stimuli associated with hosts. The results further show that the solid black surface of the original HDT design is more effective than the other surfaces (white or black/white patterns) for the capture of Ae. aegypti.

scholarly journals The need for practical insecticide-resistance guidelines to effectively inform mosquito-borne disease control programs

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Alice Namias ◽  
Ndey Bassin Jobe ◽  
Krijn Petrus Paaijmans ◽  
Silvie Huijben
Keyword(s):  
Insecticide Resistance ◽  
Disease Control ◽  
Vector Control ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Exposure Dose ◽  
Local Conditions ◽  
Control Programs ◽  
Host Seeking ◽  
Seeking Behavior

Monitoring local mosquito populations for insecticide resistance is critical for effective vector-borne disease control. However, widely used phenotypic assays, which are designed to monitor the emergence and spread of insecticide resistance (technical resistance), do not translate well to the efficacy of vector control products to suppress mosquito numbers in the field (practical resistance). This is because standard testing conditions such as environmental conditions, exposure dose, and type of substrate differ dramatically from those experienced by mosquitoes under field conditions. In addition, field mosquitoes have considerably different physiological characteristics such as age and blood-feeding status. Beyond this, indirect impacts of insecticide resistance and/or exposure on mosquito longevity, pathogen development, host-seeking behavior, and blood-feeding success impact disease transmission. Given the limited number of active ingredients currently available and the observed discordance between resistance and disease transmission, we conclude that additional testing guidelines are needed to determine practical resistance—the efficacy of vector control tools under relevant local conditions— in order to obtain programmatic impact.

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