scholarly journals General visual and contingent thermal cues interact to elicit attraction in female Aedes aegypti mosquitoes

2019 ◽  
Author(s):  
Molly Z Liu ◽  
Leslie B. Vosshall
Keyword(s):  
Aedes Aegypti ◽  
Egg Production ◽  
Visual Cues ◽  
Sensory Information ◽  
Blood Feeding ◽  
Exhaled Breath ◽  
Visual Cue ◽  
Ambient Temperatures ◽  
Visual Contrast ◽  
Host Seeking

ABSTRACTFemale Aedes aegypti mosquitoes use multiple sensory modalities to hunt human hosts to obtain a blood-meal for egg production. Attractive cues include carbon dioxide (CO2), a major component of exhaled breath [1, 2]; heat elevated above ambient temperature, signifying warm-blooded skin [3, 4]; and dark visual contrast [5, 6], proposed to bridge long-range olfactory and short-range thermal cues [7]. Any of these sensory cues in isolation is an incomplete signal of a human host, and so a mosquito must integrate multi-modal sensory information before committing to approaching and biting a person [8]. Here, we study the interaction of visual cues, heat, and CO2 to investigate the contributions of human-associated stimuli to host-seeking decisions. We show that tethered flying mosquitoes strongly orient toward dark visual contrast regardless of CO2 stimulation and internal host-seeking status. This suggests that attraction to visual contrast is general, and not contingent on other host cues. In free-flight experiments with CO2, adding a dark contrasting visual cue to a warmed surface enhanced host-seeking. Moderate warmth became more attractive to mosquitoes, and mosquitoes aggregated on the cue at all non-noxious temperatures. Gr3 mutants, unable to detect CO2, were lured to the visual cue at ambient temperatures, but fled and did not return when the surface was warmed to host-like temperatures. This suggests that attraction to thermal cues is contingent on the presence of the additional human sensory cue CO2. Our results illustrate that mosquitoes integrate general attractive visual stimuli with the context-dependent thermal stimuli to seek promising sites for blood-feeding.GRAPHICAL ABSTRACT

scholarly journals Visual threats reduce blood-feeding and trigger escape responses in Aedes aegypti mosquitoes.

2022 ◽  
Author(s):  
Nicole E Wynne ◽  
Karthikeyan Chandrasegaran ◽  
Lauren Fryzlewicz ◽  
Clément Vinauger
Keyword(s):  
Aedes Aegypti ◽  
Behavioral Response ◽  
Visual Information ◽  
Visual Cues ◽  
Blood Feeding ◽  
Potential Threat ◽  
Visual Component ◽  
Defensive Behaviors ◽  
Escape Responses

The diurnal mosquitoes Aedes aegypti are vectors of several arboviruses, including dengue, yellow fever, and Zika viruses. To find a host to feed on, they rely on the sophisticated integration of olfactory, visual, thermal, and gustatory cues reluctantly emitted by the hosts. If detected by their target, this latter may display defensive behaviors that mosquitoes need to be able to detect and escape. In humans, a typical response is a swat of the hand, which generates both mechanical and visual perturbations aimed at a mosquito. While the neuro-sensory mechanisms underlying the approach to the host have been the focus of numerous studies, the cues used by mosquitoes to detect and identify a potential threat remain largely understudied. In particular, the role of vision in mediating mosquitoes' ability to escape defensive hosts has yet to be analyzed. Here, we used programmable visual displays to generate expanding objects sharing characteristics with the visual component of an approaching hand and quantified the behavioral response of female mosquitoes. Results show that Ae. aegypti is capable of using visual information to decide whether to feed on an artificial host mimic. Stimulations delivered in a LED flight arena further reveal that landed females Ae. aegypti display a stereotypical escape strategy by taking off at an angle that is a function of the distance and direction of stimulus introduction. Altogether, this study demonstrates mosquitoes can use isolated visual cues to detect and avoid a potential threat.

scholarly journals Human blood microRNA hsa-miR-21-5p induces vitellogenin in the mosquito Aedes aegypti

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hugo D. Perdomo ◽  
Mazhar Hussain ◽  
Rhys Parry ◽  
Kayvan Etebari ◽  
Lauren M. Hedges ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Human Blood ◽  
Egg Production ◽  
Fat Body ◽  
Blood Feeding ◽  
Mosquito Vectors ◽  
Progeny Production ◽  
Proteomics Analysis ◽  
Gene Coding ◽  
Reproductive Events

AbstractMosquito vectors transmit various diseases through blood feeding, required for their egg development. Hence, blood feeding is a major physiological event in their life cycle, during which hundreds of genes are tightly regulated. Blood is a rich source of proteins for mosquitoes, but also contains many other molecules including microRNAs (miRNAs). Here, we found that human blood miRNAs are transported abundantly into the fat body tissue of Aedes aegypti, a key metabolic center in post-blood feeding reproductive events, where they target and regulate mosquito genes. Using an artificial diet spiked with the mimic of an abundant and stable human blood miRNA, hsa-miR-21-5p, and proteomics analysis, we found over 40 proteins showing differential expression in female Ae. aegypti mosquitoes after feeding. Of interest, we found that the miRNA positively regulates the vitellogenin gene, coding for a yolk protein produced in the mosquito fat body and then transported to the ovaries as a protein source for egg production. Inhibition of hsa-miR-21-5p followed by human blood feeding led to a statistically insignificant reduction in progeny production. The results provide another example of the involvement of small regulatory molecules in the interaction of taxonomically vastly different taxa.

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.

Opposite influences of host anaemia on blood feeding rate and fecundity of mosquitoes

Parasitology ◽  
1992 ◽  
Vol 105 (2) ◽  
pp. 159-163 ◽  
Author(s):  
J.-N. Shieh ◽  
P. A. Rossignol
Keyword(s):  
Theoretical Model ◽  
Aedes Aegypti ◽  
Yellow Fever ◽  
Egg Production ◽  
Feeding Rate ◽  
Fluid Intake ◽  
Capillary Flow ◽  
Blood Feeding ◽  
Negative Influence ◽  
Yellow Fever Mosquito

SUMMARYWe tested a theoretical model based on the physics of capillary flow and confirmed that anaemia accelerates blood intake in the yellow-fever mosquito, Aedes aegypti (L.). We also investigated the influence of anaemic blood on egg production of mosquitoes and found that it has a negative influence on fecundity. Based strictly on egg production and the physics of fluid intake, we propose that although anaemia associated with blood-borne parasites may be detrimental to mosquitoes that can engorge to repletion in one session, it may be beneficial to those interrupted before repletion because the greater quantity of the bloodmeal may compensate for its lower quality. Epidemiological consequences are discussed but require further inquiry.

scholarly journals Human Odour Coding in the Yellow Fever Mosquito, Aedes aegypti

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhou Chen ◽  
Feng Liu ◽  
Nannan Liu
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Blood Feeding ◽  
Chemical Information ◽  
Response Patterns ◽  
Yellow Fever Mosquito ◽  
Olfactory Sensilla ◽  
Host Seeking ◽  
Temporal Structures ◽  
Different Response

Abstract Insects use their olfactory systems to obtain chemical information on mating partners, oviposition sites and food. The yellow fever mosquito Aedes aegypti, an important vector of human infectious diseases, shows strong preference for human blood meals. This study investigated the chemical basis of host detection by characterizing the neuronal responses of antennal olfactory sensilla of female Ae. aegypti to 103 compounds from human skin emanations. The effect of blood feeding on the responses of olfactory sensilla to these odorants was examined as well. Sensilla SBTII, GP, and three functional subtypes of SST (SST1, SST2, and SST3) responded to most of the compounds tested. Olfactory receptor neurons (ORNs) ‘A’ and ‘B’ in the trichoid sensilla, either activated or inhibited, were involved in the odour coding process. Compounds from different chemical classes elicited responses with different temporal structures and different response patterns across the olfactory sensilla. Except for their increased responses to several odorants, blood-fed mosquitoes generally evoked reduced responses to specific aldehydes, alcohols, aliphatics/aromatics, ketones, and amines through the SST1, SST2, SBTI, SBTII and GP sensilla. The odorants eliciting diminished responses in female mosquitoes after blood feeding may be important in Ae. aegypti host-seeking activity and thus can be candidates for mosquito attractants in the process of this disease vector management.

scholarly journals Temperature and Sugar Feeding Effects on the Activity of a Laboratory Strain of Aedes aegypti

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 347 ◽  
Author(s):  
Irvin Forde Upshur ◽  
Elizabeth Annadel Bose ◽  
Cameron Hart ◽  
Chloé Lahondère
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Species ◽  
Thermal Conditions ◽  
Laboratory Strain ◽  
Blood Feeding ◽  
Effect Of Temperature ◽  
Total Carbohydrate ◽  
Sugar Feeding ◽  
Host Seeking ◽  
Invasive Mosquito

Aedes aegypti is an invasive mosquito species that is expected to expand its global distribution through climate change. As poikilotherms, mosquitoes are greatly affected by the temperature of the environment which can impact host-seeking, blood-feeding, and flight activity as well as survival and ability to transmit pathogens. However, an important aspect of mosquito biology on which the effect of temperature has not been investigated is water and sugar-feeding and how access to a sugar source might affect the insect’s activity and survival under different thermal conditions. To close this knowledge gap, we relied on actometer experiments to study the activity of both female and male Ae. aegypti at 20 °C, 25 °C, and 30 °C, providing either water or 10% sucrose to the insects. We then measured the total carbohydrate contents of alive mosquitoes using the anthrone protocol. Survival was assessed and compared between all groups. Results from this study will inform on the thermal biology of Ae. aegypti mosquitoes and how access to sugar affects their activity.

scholarly journals The impact of mating and sugar feeding on blood-feeding physiology and behavior in the arbovirus vector mosquito Aedes aegypti

2021 ◽  
Vol 15 (9) ◽  
pp. e0009815
Author(s):  
Garrett P. League ◽  
Ethan C. Degner ◽  
Sylvie A. Pitcher ◽  
Yassi Hafezi ◽  
Erica Tennant ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Egg Production ◽  
Control Strategies ◽  
Blood Feeding ◽  
Female Behavior ◽  
Sugar Feeding ◽  
And Behavior ◽  
The Impact ◽  
Initial Blood

Background Aedes aegypti mosquitoes are globally distributed vectors of viruses that impact the health of hundreds of millions of people annually. Mating and blood feeding represent fundamental aspects of mosquito life history that carry important implications for vectorial capacity and for control strategies. Females transmit pathogens to vertebrate hosts and obtain essential nutrients for eggs during blood feeding. Further, because host-seeking Ae. aegypti females mate with males swarming near hosts, biological crosstalk between these behaviors could be important. Although mating influences nutritional intake in other insects, prior studies examining mating effects on mosquito blood feeding have yielded conflicting results. Methodology/Principal findings To resolve these discrepancies, we examined blood-feeding physiology and behavior in virgin and mated females and in virgins injected with male accessory gland extracts (MAG), which induce post-mating changes in female behavior. We controlled adult nutritional status prior to blood feeding by using water- and sugar-fed controls. Our data show that neither mating nor injection with MAG affect Ae. aegypti blood intake, digestion, or feeding avidity for an initial blood meal. However, sugar feeding, a common supplement in laboratory settings but relatively rare in nature, significantly affected all aspects of feeding and may have contributed to conflicting results among previous studies. Further, mating, MAG injection, and sugar intake induced declines in subsequent feedings after an initial blood meal, correlating with egg production and laying. Taking our evaluation to the field, virgin and mated mosquitoes collected in Colombia were equally likely to contain blood at the time of collection. Conclusions/Significance Mating, MAG, and sugar feeding impact a mosquito’s estimated ability to transmit pathogens through both direct and indirect effects on multiple aspects of mosquito biology. Our results highlight the need to consider natural mosquito ecology, including diet, when assessing their physiology and behavior in the laboratory.

scholarly journals Investigation of Relative Development and Reproductivity Fitness Cost in Three Insecticide-Resistant Strains of Aedes aegypti from Thailand

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 265 ◽  
Author(s):  
Jassada Saingamsook ◽  
Jintana Yanola ◽  
Nongkran Lumjuan ◽  
Catherine Walton ◽  
Pradya Somboon
Keyword(s):  
Aedes Aegypti ◽  
Egg Production ◽  
Natural Populations ◽  
Blood Feeding ◽  
Developmental Time ◽  
Resistance Mechanisms ◽  
Fitness Cost ◽  
Detoxification Enzymes ◽  
Relative Fitness ◽  
Resistant Strains

Knockdown resistance (kdr) and detoxification enzymes are major resistance mechanisms in insecticide-resistant Aedes aegypti throughout the world. Persistence of the resistance phenotype is associated with high fitness of resistance alleles in the absence of insecticide pressure. This study determined the relative fitness cost of three insecticide-resistant strains of Aedes aegypti—PMD, PMD-R, and UPK-R—and a hybrid under similar laboratory conditions in the absence of insecticide. The PMD strain is resistant to DDT with no kdr alleles; the PMD-R is resistant to DDT and permethrin with 1534C homozygous kdr alleles; and UPK-R is resistant to DDT, permethrin, and deltamethrin with 989P + 1016G homozygous alleles. The DDT-resistant PMD strain had the highest fitness compared with the two DDT/pyrethroid-resistant strains (PMD-R and UPK-R) and hybrid. Consistent fitness costs were observed in the DDT/pyrethroid-resistant strains and hybrid, including shorter wing length, reduced egg hatchability, shorter female lifespan, and shorter viability of eggs after storage, whereas no effect was observed on blood feeding rate. In addition, reduced egg production was observed in the PMD-R strain and prolonged developmental time was seen in the UPK-R strain. The corresponding hybrid that is heterozygous for kdr alleles was fitter than either of the homozygous mutant genotypes. This is in accordance with the high frequency of heterozygous genotypes observed in natural populations of Ae. aegypti in Chiang Mai city.

scholarly journals Community-level impacts of spatial repellents for control of diseases vectored by Aedes aegypti mosquitoes

2019 ◽  
Author(s):  
Quirine A. ten Bosch ◽  
Joseph M. Wagman ◽  
Fanny Castro-Llanos ◽  
Nicole L. Achee ◽  
John P. Grieco ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aedes Aegypti ◽  
Lethal Effect ◽  
Blood Feeding ◽  
Small Scale ◽  
Substantial Impact ◽  
Force Of Infection ◽  
Host Seeking ◽  
Spatial Repellents ◽  
Epidemiological Impact

AbstractSpatial repellents (SRs) reduce human-mosquito contact by preventing mosquito entrance into human-occupied spaces and interfering with host-seeking and blood-feeding. A new model to synthesize experimental data on the effects of transfluthrin on Aedes aegypti explores how SR effects interact to impact the epidemiology of diseases vectored by these mosquitoes. Our results indicate that the greatest impact on force of infection is expected to derive from the chemical’s lethal effect but delayed biting and associated negative feedbacks on the vector population could elicit substantial impact in the absence of lethality. The relative contributions of these effects depend on coverage, chemical dose, mechanism of action, and housing density. We also demonstrate potential adverse impacts of increased partial blood-feeding and reduced exiting, which could offset gains achieved by other effects. Our analysis demonstrates how small-scale experimental data can be leveraged to derive expectations of epidemiological impact of SRs deployed at larger scales.

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