scholarly journals Computational and experimental insights into the chemosensory navigation ofAedes aegyptimosquito larvae

2019 ◽  
Author(s):  
Eleanor K. Lutz ◽  
Tjinder S. Grewal ◽  
Jeffrey A. Riffell
Keyword(s):  
Search Behavior ◽  
Larval Habitat ◽  
Disease Vectors ◽  
Mosquito Larvae ◽  
Chemical Gradients ◽  
Host Seeking ◽  
Behavioral Mechanism ◽  
Computational Analyses ◽  
And Control ◽  
Chemosensory Behavior

AbstractMosquitoes are prolific disease vectors that affect public health around the world. Although many studies have investigated search strategies used by host-seeking adult mosquitoes, little is known about larval search behavior. Larval behavior affects adult body size and fecundity, and thus the capacity of individual mosquitoes to find hosts and transmit disease. Understanding vector survival at all life stages is crucial for improving disease control. In this study we use experimental and computational methods to investigate the chemical ecology and search behavior ofAedes aegyptimosquito larvae. We show that larvae do not respond to several olfactory cues used by adultAe. aegyptito assess larval habitat quality, but perceive microbial RNA as a potent foraging attractant. Second, we demonstrate thatAe. aegyptilarvae use a strategy consistent with chemokinesis, rather than chemotaxis, to navigate chemical gradients. Using computational modeling, we further show that chemokinesis is more efficient than chemotaxis for avoiding repellents in ecologically relevant larval habitat sizes. Finally, we use experimental observations and computational analyses to demonstrate that larvae respond to starvation pressure by optimizing exploration behavior. Our results identify key characteristics of foraging behavior in a disease vector mosquito, including the identification of a surprising foraging attractant and an unusual behavioral mechanism for chemosensory preference. In addition to implications for better understanding and control of disease vectors, this work establishes mosquito larvae as a tractable model for chemosensory behavior and navigation.

scholarly journals Computational and experimental insights into the chemosensory navigation o f Aedes aegypti mosquito larvae

2019 ◽  
Vol 286 (1915) ◽  
pp. 20191495 ◽  
Author(s):  
Eleanor K. Lutz ◽  
Tjinder S. Grewal ◽  
Jeffrey A. Riffell
Keyword(s):  
Aedes Aegypti ◽  
Computational Modelling ◽  
Larval Habitat ◽  
Disease Vectors ◽  
Mosquito Larvae ◽  
Search Behaviour ◽  
Chemical Gradients ◽  
Larval Behaviour ◽  
Host Seeking ◽  
And Control

Mosquitoes are prolific disease vectors that affect public health around the world. Although many studies have investigated search strategies used by host-seeking adult mosquitoes, little is known about larval search behaviour. Larval behaviour affects adult body size and fecundity, and thus the capacity of individual mosquitoes to find hosts and transmit disease. Understanding vector survival at all life stages is crucial for improving disease control. In this study, we use experimental and computational methods to investigate the chemical ecology and search behaviour of Aedes aegypti mosquito larvae. We first show that larvae do not respond to several olfactory cues used by adult Ae. aegypti to assess larval habitat quality, but perceive microbial RNA as a potent foraging attractant. Second, we demonstrate that Ae. aegypti larvae use chemokinesis, an unusual search strategy, to navigate chemical gradients. Finally, we use computational modelling to demonstrate that larvae respond to starvation pressure by optimizing exploration behaviour—possibly critical for exploiting limited larval habitat types. Our results identify key characteristics of foraging behaviour in an important disease vector mosquito. In addition to implications for better understanding and control of disease vectors, this work establishes mosquito larvae as a tractable model for chemosensory behaviour and navigation.

scholarly journals The Use of Granular Cyclopentanone as Alternative to Artificial Source of Carbon Dioxide in Improved Passive Outdoor Host Seeking Device (POHD)

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Stella T. Kessy ◽  
Bruno A. Nyundo ◽  
Ladslaus L. Mnyone ◽  
Issa N. Lyimo
Keyword(s):  
Electrical Power ◽  
Scale Up ◽  
Residual Activity ◽  
Yeast Fermentation ◽  
Power Sources ◽  
Host Seeking ◽  
Relative Attractiveness ◽  
Residual Malaria Transmission ◽  
Control Devices ◽  
And Control

Reliable sources of CO2 that are relatively cheap, obtainable, and easy to sustain are immediately required for scaling up of odor-baited mosquito surveillance and control devices. Several odor-baited devices are in the pipeline; however, their scale-up against residual malaria transmission, particularly in resource poor areas, is limited by the unavailability of reliable sources of CO2 and reliance on electrical power sources among other factors. We evaluated the use of granular cyclopentanone as an alternative to artificial or yeast fermentation-produced CO2 in passive outdoor host seeking device (POHD). Experiments were conducted against semifield reared An. arabiensis within the semifield system (SFS) at Ifakara Health Institute. Mosquitoes were tested against odor-baited POHDs augmented with yeast fermentation-produced CO2, granular cyclopentanone, attractive blends (Mbita or Ifakara), or their combinations. An insecticide, bendiocarb, was a killing agent used as a proxy for marking the mosquitoes visit the POHDs. Relative attractiveness of different treatment combinations was compared based on the proportion of dead mosquitoes that visited the POHD. The POHD augmented with granules of cyclopentanone alone was attractive to An. arabiensis as much as, or more than, POHDs augmented with yeast fermentation-produced CO2. The POHD baited with CO2 attracted more mosquitoes than those POHDs baited with synthetic blends alone; when these blends are combined with CO2, they attracted more mosquitoes than individual blends. More importantly, such POHDs baited with cyclopentanone attracted far greater proportion of mosquitoes than the POHD baited with either Mbita or Ifakara blend alone. The granular cyclopentanone strongly enhanced/potentiated the attractiveness of POHD baited with Mbita blends against mosquitoes compared to that of POHD baited with Ifakara blend. Moreover, the granular cyclopentanone retained its residual activity against An. arabiensis for up to 2 months after application particularly when used in combination with Mbita blend. In conclusion, this study demonstrates that cyclopentanone granules have the potential to substitute sources of CO2 in outdoor-based surveillance and control devices, thus warranting evaluation of such alternative under realistic field conditions.

scholarly journals Effect of Dinotefuran, Permethrin, and Pyriproxyfen (Vectra® 3D) on the Foraging and Blood-Feeding Behaviors of Aedes albopictus Using Laboratory Rodent Model

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 507
Author(s):  
Younes Laidoudi ◽  
Djamel Tahir ◽  
Hacène Medkour ◽  
Marie Varloud ◽  
Oleg Mediannikov ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Selection Index ◽  
Exposure Period ◽  
Blood Feeding ◽  
Feeding Behaviors ◽  
Host Seeking ◽  
Seeking Behavior ◽  
Feeding Effect ◽  
Rats And Mice ◽  
And Control

Dinotefuran-Permethrin-Pyriproxyfen (DPP) is used to kill and repel mosquitoes from dogs. However, the influence of the product on the host-seeking behavior of mosquitoes remains unknown. The interference of DPP with the host selection of unfed female Aedes albopictus was investigated. A total of 18 animals (9 mice and 9 rats) were divided into three groups of six animals each. DU: DPP treated rats (n = 3) with untreated mice (n = 3), UD: DPP treated mice (n = 3) with untreated rats (n = 3) and control UU: untreated mice (n = 3) and untreated rats (n = 3). In each group, the rats and mice were placed 30 cm apart. After sedation, the animals in each group were exposed twice (Day 1 and Day 7 post-treatment) for one hour to 71 ± 3 female mosquitoes. Mosquitoes were categorized after the 2-h post-exposure period as dead or alive. Blood-meal origin was determined from mosquitoes using a newly customized duplex qPCR. The highest values of forage ratio (1.36 ≥ wi ≤ 1.88) and selection index (0.63 ≥ Bi ≤ 0.94) for rat hosts indicates a preference of mosquitoes for this species as compared to mice when co-housed during the exposure. The mosquitoes only seldom fed on mice, even in the untreated group. The anti-feeding effect of DPP was therefore only assessed on rat’s hosts. The results showed that DPP, when directly applied on rats, provided a direct protection of 82% and 61% on Day 1 and Day 7, respectively, while when applied on mice hosts (UD), the DPP provided an indirect protection of 21% and 10% on Day 1 and Day 7, respectively. The results showed also that DPP, when applied on rats, provided a direct protection against Ae. albopictus bites. This effect did not result in increased exposure of the untreated host placed in the same cage at a distance of 30 cm.

Species composition and abundance of mosquito larvae in relation with their habitat characteristics in Mazandaran Province, northern Iran

2017 ◽  
Vol 107 (5) ◽  
pp. 598-610 ◽  
Author(s):  
S.H. Nikookar ◽  
M. Fazeli-Dinan ◽  
S. Azari-Hamidian ◽  
S.N. Mousavinasab ◽  
M. Arabi ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Larval Density ◽  
Larval Habitat ◽  
Habitat Characteristics ◽  
Mosquito Larvae ◽  
Mazandaran Province ◽  
Natural Habitats ◽  
Northern Iran ◽  
Monthly Basis ◽  
Larval Habitats

AbstractMosquitoes transmit a variety of diseases to humans. Their abundance and distribution are related to the characteristics of larval habitats. Mosquito larvae were collected from 120 natural and artificial habitats in 30 villages of 16 counties using standard 350 ml dippers and pipette, on a monthly basis from May–December 2014 in Mazandaran Province, northern Iran. Larval habitat characteristics were recorded separately, based on the conditions of the habitats (permanent or temporary, stagnant or running), type of habitats (natural or artificial), vegetation, exposure to sun, type of bed, water condition (clear or turbid), expanse (m), depth (cm, m) and temperature (°C) of habitats. The relationship between larval density and environmental variables was assessed by Chi-square tests. Totally, 19,840 larvae from three genera and 16 species were collected and identified.Anopheles maculipennis s.l.andCulex pipienswere the dominant species and collected with the highest density in plain areas. The highest number of larvae were collected from natural habitats (60.34%), including; river edge, marsh, pit and wetlands; with temporary and stagnant water, expanse of 0–5 m, depth of 1–25 cm, without plant, shadow-sun, muddy floor, turbid water, temperature 20–25°C and in sunny conditions. River edge and rice fields forAn. maculipennis s.land, wetlands and discarded tires forCx. pipienswere the main larval habitats in the province. Statistical analysis revealed significant relation between occurrence ofAn. maculipennis s.l., Cx. pipiens, Culex torrentium, Culex mimeticusandCs. annulatawith each of the environmental variables (P< 0.001). These findings are essential in expanding our knowledge of the vectors ecology specially the type of habitat preference and will be beneficial in larval control programs.

scholarly journals Measuring concentration fields in microfluidic channels in situ with a Fabry–Perot interferometer

Lab on a Chip ◽  
2015 ◽  
Vol 15 (7) ◽  
pp. 1689-1696 ◽  
Author(s):  
Douglas R. Vogus ◽  
Vincent Mansard ◽  
Michael V. Rapp ◽  
Todd M. Squires
Keyword(s):  
Fluorescent Labeling ◽  
Microfluidic Channels ◽  
Concentration Profiles ◽  
Complex Chemical ◽  
Chemical Gradients ◽  
Microfluidic Technology ◽  
Fabry Perot ◽  
Spatio Temporal ◽  
And Control

Recent advancements in microfluidic technology have allowed for the generation and control of complex chemical gradients; however, few general techniques can measure these spatio-temporal concentration profiles without fluorescent labeling.

scholarly journals Mosquito Larvae (Culex spp.) Startle Responses to Vibration Stimuli

2021 ◽  
Author(s):  
Ellie R. Harrison ◽  
William J. Budenberg
Keyword(s):  
Startle Response ◽  
Environmental Effect ◽  
Video Tracking ◽  
Learning Ability ◽  
Mosquito Larvae ◽  
Environmental Chamber ◽  
Live Video ◽  
And Control ◽  
Behavioural Toxicology ◽  
Insight Into

AbstractWe explored startle responses of Culex spp. larvae to varying frequencies and durations of vibrations, before investigating habituation (a behavioural learning phenomenon). The startle response consists of a rapid movement to permit escape from a potentially dangerous stimulus. We used the automated Zantiks MWP_vb unit to analyse larval startle responses through the built-in live video tracking. Set within the unit’s controlled environmental chamber, we recorded distance travelled by the larvae. These results were used to optimise the vibration startle response for use in habituation studies. Repeated vibrations appeared to reduce larvae startle responses, although further analysis is required to confirm habituation. This study not only provides an insight into the learning ability of mosquito larvae, but demonstrates the ease, replicability and control conferred by the automated unit. Furthermore, this method is applicable to many other organisms and shows potential for more sophisticated environmental effect testing, such as behavioural toxicology.

scholarly journals Australian mosquito assemblages vary between ground and sub-canopy habitats

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Boni F. Sebayang ◽  
Tanya L. Russell ◽  
Kyran M. Staunton ◽  
Michael Townsend ◽  
Christopher Paton ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mosquito Species ◽  
Species Abundance ◽  
Latin Square ◽  
Ground Level ◽  
Larval Habitat ◽  
Resting Behaviour ◽  
Trap Height ◽  
Host Blood ◽  
And Control

Abstract Background The surveillance and control of mosquito-borne diseases is dependent upon understanding the bionomics and distribution of the vectors. Most studies of mosquito assemblages describe species abundance, richness and composition close to the ground defined often by only one sampling method. In this study, we assessed Australian mosquito species near the ground and in the sub-canopy using two traps baited with a variety of lures. Methods Mosquitoes were sampled using a 4 × 4 Latin square design at the Cattana Wetlands, Australia from February to April 2020, using passive box traps with octenol and carbon dioxide and three variations of a sticky net trap (unbaited, and baited with octenol or octenol and carbon dioxide). The traps were deployed at two different heights: ground level (≤ 1 m above the ground) and sub-canopy level (6 m above the ground). Results In total, 27 mosquito species were identified across the ground and sub-canopy levels from the different traps. The abundance of mosquitoes at the ground level was twofold greater than at the sub-canopy level. While the species richness at ground and sub-canopy levels was not significantly different, species abundance varied by the collection height. Conclusions The composition of mosquito population assemblages was correlated with the trap types and heights at which they were deployed. Coquillettidia species, which prefer feeding on birds, were mainly found in the sub-canopy whereas Anopheles farauti, Aedes vigilax and Mansonia uniformis, which have a preference for feeding on large mammals, were predominantly found near the ground. In addition to trap height, environmental factors and mosquito bionomic characteristics (e.g. larval habitat, resting behaviour and host blood preferences) may explain the vertical distribution of mosquitoes. This information is useful to better understand how vectors may acquire and transmit pathogens to hosts living at different heights. Graphical abstract

scholarly journals Odonata: Who They Are and What They Have Done for Us Lately: Classification and Ecosystem Services of Dragonflies

Insects ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 62 ◽  
Author(s):  
Michael May
Keyword(s):  
Ecosystem Services ◽  
Aquatic Ecosystems ◽  
Insect Flight ◽  
Economic Importance ◽  
Molecular Techniques ◽  
Disease Vectors ◽  
Agricultural Pests ◽  
Top Predators ◽  
New Information ◽  
And Control

Odonata (dragonflies and damselflies) are well-known but often poorly understood insects. Their phylogeny and classification have proved difficult to understand but, through use of modern morphological and molecular techniques, is becoming better understood and is discussed here. Although not considered to be of high economic importance, they do provide esthetic/spiritual benefits to humans, and may have some impact as predators of disease vectors and agricultural pests. In addition, their larvae are very important as intermediate or top predators in many aquatic ecosystems. More recently, they have been the objects of study that have yielded new information on the mechanics and control of insect flight.

scholarly journals A Qualitative Evidence of the Breeding Sites of Anopheles arabiensis Patton (Diptera: Culicidae) in and Around Kassala Town, Eastern Sudan

2016 ◽  
Vol 8 ◽  
pp. IJIS.S40071 ◽  
Author(s):  
Asma Mahmoud Hamza ◽  
El Amin El Rayah
Keyword(s):  
Anopheles Arabiensis ◽  
Habitat Type ◽  
Larval Habitat ◽  
Mosquito Larvae ◽  
Habitat Types ◽  
Breeding Sites ◽  
Water Pipes ◽  
Control Programs ◽  
Qualitative Evidence ◽  
Eastern Sudan

Anopheles arabiensis Patton (Diptera: Culicidae) is considered the most efficient malaria vector in eastern Sudan. This study aims to characterize the breeding sites of An. arabiensis throughout the year in and around Kassala town, eastern Sudan. Diverse larval habitat types were visited and characterized based on the habitat type and chemical composition. Mosquito larvae were found in many diverse habitats. During the rainy season, rain pools and water bodies created by the seasonal Gash River serve as the main breeding sites. In the dry season, irrigation canals, seepage from water pipes, neglected wells, artificial containers, and man-made ditches serve as the main breeding sites. Breeding water showed a pH of 7.9 and a low concentration of the total dissolved salts. The results of this study may be considered in planning and implementing larval control programs in the area.

How Do We See COVID-19? Visual Iconographies of Racial Contagion

2020 ◽  
Vol 92 (4) ◽  
pp. 707-722
Author(s):  
Kirsten Ostherr
Keyword(s):  
Health Workers ◽  
Disease Outbreaks ◽  
Health Science ◽  
Disease Vectors ◽  
The Public ◽  
Naked Eye ◽  
Core Set ◽  
Meaning Production ◽  
And Control ◽  
Global And Local

Abstract Contagion media have historically performed the dual functions of scientific and ideological persuasion, often deploying an iconography of racial contagion that combines these two functions. In efforts to halt the spread of the virus, health, science, and media organizations create visual imagery to teach the public to imagine we can see and therefore avoid contaminants that are invisible to the naked eye. Comparison of COVID-19 with other global disease outbreaks shows how a core set of contagion media visualizations are repeatedly deployed with subtle adaptations for unique diseases and display interfaces. The variations among different corpora of contagion media point to the interplay among persistent, transhistorical tropes, particular sites of meaning production, and novel technical affordances. This article will examine a subset of these representational techniques, including microscopic images of the virus, close-ups of disease vectors, global and local maps of contagion, health workers in biohazard suits, and visibly ill patients. The essay argues that techniques for visualizing the invisible produce a narrative logic of causality in COVID-19 that reinforces racist and xenophobic discourses of containment and control with direct and deadly consequences. Mitigation of this pandemic and future pandemics will require not only medical but also representational interventions.

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