scholarly journals Long-Range But Not Short-Range Attraction of Male Aedes aegypti (Diptera: Culicidae) Mosquitoes to Humans

2021 ◽  
Author(s):  
Brogan A Amos ◽  
Ary A Hoffmann ◽  
Kyran M Staunton ◽  
Meng-Jia Lau ◽  
Thomas R Burkot ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Short Range ◽  
Human Subjects ◽  
Behavioral Differences ◽  
Baited Traps ◽  
Assay Design ◽  
And Control ◽  
Male Mosquito ◽  
Blood Meals ◽  
Host Cues

Abstract Female Aedes aegypti (Linnaeus) mosquitoes integrate multiple sensory cues to locate human hosts for blood meals. Although male Ae. aegypti swarm around and land on humans in nature to mate, direct evidence of attraction to humans is limited. Male mosquito attraction to human host cues is often undetectable in confined laboratory assays, leading to a misconception that male mosquitoes are not attracted to humans. We used semifield experiments to demonstrate robust attraction of male Ae. aegypti to humans. Human-baited traps captured up to 25% of released males within 15 min, whereas control traps without humans as bait failed to capture males. Rapid attraction to humans was further demonstrated through videography. Males swarmed around and landed on human subjects, with no activity recorded in paired unbaited controls. Finally, we confirm the lack of discernible male attraction to humans in small laboratory cages. Our experiments demonstrate that both male and female Ae. aegypti show attraction to humans, but with clear sex-specific behavioral differences at short-range. Male mosquito attraction to humans is likely to be important for mating success in wild populations and its basis should be further explored. Our results highlight the importance of arena size and assay design for mosquito behavioral research. A better understanding of host cues that attract males could help us to improve mosquito surveillance and control.

scholarly journals Lure, retain, and catch malaria mosquitoes. How heat and humidity improve odour-baited trap performance

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Antoine Cribellier ◽  
Jeroen Spitzen ◽  
Henry Fairbairn ◽  
Cedric van de Geer ◽  
Johan L. van Leeuwen ◽  
...  
Keyword(s):  
Short Range ◽  
Visual Cues ◽  
Three Dimensional ◽  
Field Testing ◽  
Counter Flow ◽  
Flight Behaviour ◽  
Baited Traps ◽  
Close Range ◽  
Malaria Mosquitoes ◽  
Host Cues

Abstract Background When seeking a human for a blood meal, mosquitoes use several cues to detect and find their hosts. From this knowledge, counter-flow odour-baited traps have been developed that use a combination of CO2, human-mimicking odour, visual cues and circulating airflow to attract and capture mosquitoes. Initially developed for monitoring, these traps are now also being considered as promising vector control tools. The traps are attractive to host-seeking mosquitoes, but their capture efficiency is low. It has been hypothesized that the lack of short-range host cues, such as heat and increased local humidity, often prevent mosquitoes from getting close enough to get caught; this lack might even trigger avoidance manoeuvres near the capture region. Methods This study investigated how close-range host cues affect the flight behaviour of Anopheles female malaria mosquitoes around odour-baited traps, and how this affects trap capture performance. For this, a novel counter-flow odour-baited trap was developed, the M-Tego. In addition to the usual CO2 and odour-blend, this trap can provide the short-range host cues, heat and humidity. Systematically adding or removing these two cues tested how this affected the trap capture percentages and flight behaviour. First, capture percentages of the M-Tego with and without short-range host cues to the BG-Suna trap were compared, in both laboratory and semi-field testing. Then, machine-vision techniques were used to track the three-dimensional flight movements of mosquitoes around the M-Tego. Results With heat and humidity present, the M-Tego captured significantly more mosquitoes as capture percentages almost doubled. Comparing the flight behaviour around the M-Tego with variable close-range host cues showed that when these cues were present, flying mosquitoes were more attracted to the trap and spent more time there. In addition, the M-Tego was found to have a better capture mechanism than the BG-Suna, most likely because it does not elicit previously observed upward avoiding manoeuvres. Conclusions Results suggest that adding heat and humidity to an odour-baited trap lures more mosquitoes close to the trap and retains them there longer, resulting in higher capture performance. These findings support the development of control tools for fighting mosquito-borne diseases such as malaria.

scholarly journals Strong attraction of male mosquitoes (Aedes aegypti) to humans

2021 ◽  
Author(s):  
Brogan A Amos ◽  
Ary A Hoffmann ◽  
Kyran M Staunton ◽  
Meng-Jia Lau ◽  
Thomas R Burkot ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Field Experiments ◽  
Human Subjects ◽  
Strong Attraction ◽  
Host Seeking ◽  
Specific Trait ◽  
Female Specific ◽  
Swarming Behavior ◽  
Male Mosquito ◽  
Male Mosquitoes

Female Aedes aegypti mosquitoes integrate multiple sensory cues to locate human hosts for blood meals. While male mosquitoes do not blood feed, male Ae. aegypti swarm around and land on humans in nature. Basrur et al. (2020) generated male Aedes aegypti lacking the fruitless gene and discovered that they gained strong attraction to humans, similar to female mosquitoes. The authors assume that host-seeking is a female-specific trait, which they confirmed through experiments. However, all experiments were performed under confined laboratory conditions which appear to inhibit swarming behavior. We used semi-field experiments to demonstrate robust attraction of male Ae. aegypti to humans. Human-baited traps captured up to 25% of released males within 15 min, whereas control traps without humans as bait failed to capture males. Rapid attraction to humans was further demonstrated through videography. Males swarmed around and landed on human subjects, with no activity recorded in paired unbaited controls. The absence of female Ae. aegypti in these experiments rules out a hypothesis by Basrur et al. (2020) that males are attracted not to the human, but to host-seeking females near humans. Finally, we confirm the lack of male attraction to humans in small laboratory cages, even when using recently field-collected males. Our direct observations of male mosquito attraction to humans refute a key assumption of Basrur et al. (2020) and raise questions around conditions under which fruitless prevents male host-seeking. Male mosquito attraction to humans is likely to be important for mating success in wild populations and its basis should be further explored.

scholarly journals Temporal and Spatial Blood Feeding Patterns of Urban Mosquitoes in the San Juan Metropolitan Area, Puerto Rico

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Matthew W. Hopken ◽  
Limarie J. Reyes-Torres ◽  
Nicole Scavo ◽  
Antoinette J. Piaggio ◽  
Zaid Abdo ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Aedes Aegypti ◽  
Metropolitan Area ◽  
Culex Quinquefasciatus ◽  
Urban Ecosystems ◽  
Life Cycles ◽  
Pathogen Transmission ◽  
San Juan ◽  
Vertebrate Species ◽  
Blood Meals

Urban ecosystems are a patchwork of habitats that host a broad diversity of animal species. Insects comprise a large portion of urban biodiversity which includes many pest species, including those that transmit pathogens. Mosquitoes (Diptera: Culicidae) inhabit urban environments and rely on sympatric vertebrate species to complete their life cycles, and in this process transmit pathogens to animals and humans. Given that mosquitoes feed upon vertebrates, they can also act as efficient samplers that facilitate detection of vertebrate species that utilize urban ecosystems. In this study, we analyzed DNA extracted from mosquito blood meals collected temporally in multiple neighborhoods of the San Juan Metropolitan Area, Puerto Rico to evaluate the presence of vertebrate fauna. DNA was collected from 604 individual mosquitoes that represented two common urban species, Culex quinquefasciatus (n = 586) and Aedes aegypti (n = 18). Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Domestic chickens dominated these blood meals both temporally and spatially, and no statistically significant shift from birds to mammals was detected. Aedes aegypti blood meals were from a less diverse group, with two avian taxa (11.1%) and three mammalian taxa (88.9%) identified. The blood meals we identified provided a snapshot of the vertebrate community in the San Juan Metropolitan Area and have potential implications for vector-borne pathogen transmission.

Behavioral Effects of Prenatal and Adult Exposure To Toxic Chemicals Found in Lake Ontario Fish: Two Methodological Approaches

1996 ◽  
Vol 12 (3-4) ◽  
pp. 419-426 ◽  
Author(s):  
Helen Daly ◽  
Thomas Darvill ◽  
Edward Lonky ◽  
Jacqueline Reihman ◽  
David Sargent
Keyword(s):  
Human Subjects ◽  
Lake Ontario ◽  
Behavioral Changes ◽  
Laboratory Rats ◽  
Confounding Variables ◽  
Correlational Method ◽  
And Behavior ◽  
And Control ◽  
Adult Exposure ◽  
To Receive

Two research approaches are described that were used to determine behavioral changes following a diet of Lake Ontario fish. Approach 1 involved the correlational method, in which human subjects voluntarily ate contaminated Lake Ontario fish. Demographic information, data on the amount of Lake Ontario fish consumed, and control variables were obtained during an interview. Respondents' behavior, as well as the behavior of their children, then was measured. Because subjects were not assigned randomly to eat or not eat Lake Ontario fish, other variables that might have influenced both consumption of fish and behavior had to be considered. Therefore, confounding variables were measured and their influence controlled for using statistical techniques. Approach 2 involved the experimental method using laboratory rats, where subjects were assigned randomly to receive a diet of environmentally contaminated Lake Ontario salmon, relatively uncontaminated Pacific Ocean salmon, or no salmon. Since the rats fed Lake Ontario salmon behaved differently than the other two groups on nine tasks, it was concluded that the contaminants in Lake Ontario salmon caused behavioral changes. Random assignment of subjects to groups eliminated competing explanations. If similar behavioral (e.g., emotional or cognitive) results were obtained using the two approaches, then the results utilizing rats probably could be generalized to humans, and the correlational results found in humans probably were due to a cause and effect relationship.

Harmonic Analysis of Non-Sinusoidal Harmonic Signals in Electric Power System

2014 ◽  
Vol 1070-1072 ◽  
pp. 779-784
Author(s):  
Dan Luo ◽  
Yi Xiao ◽  
Jie Na Zhou
Keyword(s):  
Power System ◽  
Harmonic Analysis ◽  
Short Range ◽  
Time Windows ◽  
Electric Power System ◽  
Normal Operation ◽  
Calculation Error ◽  
Interpolation Algorithm ◽  
Harmonic Signals ◽  
And Control

Harmonic Analysis and control is very important for the power system because harmonics have serious harm to its normal operation. Harmonic Analysis uses fast Fourier transform (FFT) to solve this problem though it causes the spectrum leakage which Increases the calculation error. To solve this problem, the interpolation algorithm combine with tapered time windows are used. The tapered time windows solve the long-range leakage and the interpolation algorithm solves the problem of short-range leakage.

scholarly journals Field- and clinically derived estimates of Wolbachia-mediated blocking of dengue virus transmission potential in Aedes aegypti mosquitoes

2017 ◽  
Vol 115 (2) ◽  
pp. 361-366 ◽  
Author(s):  
Lauren B. Carrington ◽  
Bich Chau Nguyen Tran ◽  
Nhat Thanh Hoang Le ◽  
Tai Thi Hue Luong ◽  
Truong Thanh Nguyen ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Virus Transmission ◽  
Field Testing ◽  
Denv Infection ◽  
Ho Chi Minh City ◽  
Wild Type ◽  
Transmission Potential ◽  
Blood Meals ◽  
Increased Susceptibility

The wMel strain of Wolbachia can reduce the permissiveness of Aedes aegypti mosquitoes to disseminated arboviral infections. Here, we report that wMel-infected Ae. aegypti (Ho Chi Minh City background), when directly blood-fed on 141 viremic dengue patients, have lower dengue virus (DENV) transmission potential and have a longer extrinsic incubation period than their wild-type counterparts. The wMel-infected mosquitoes that are field-reared have even greater relative resistance to DENV infection when fed on patient-derived viremic blood meals. This is explained by an increased susceptibility of field-reared wild-type mosquitoes to infection than laboratory-reared counterparts. Collectively, these field- and clinically relevant findings support the continued careful field-testing of wMel introgression for the biocontrol of Ae. aegypti-born arboviruses.

Susceptibility Profile of Aedes aegypti L. (Diptera: Culicidae) from Montclair, California, to Commonly Used Pesticides, With Note on Resistance to Pyriproxyfen

2019 ◽  
Vol 56 (4) ◽  
pp. 1047-1054 ◽  
Author(s):  
Tianyun Su ◽  
Jennifer Thieme ◽  
Taylor Lura ◽  
Min-Lee Cheng ◽  
Michelle Q Brown
Keyword(s):  
Aedes Aegypti ◽  
The United States ◽  
Urban Environments ◽  
Sub Saharan Africa ◽  
Modes Of Action ◽  
Breeding Populations ◽  
Laboratory Colony ◽  
Sub Saharan ◽  
The Tropics ◽  
And Control

Abstract The peridomestic anthropophilic Aedes aegypti L. (Diptera: Culicidae) is originated from the wild zoophilic subspecies Aedes aegypti formosus in sub-Saharan Africa, and currently has a broad distribution in human-modified environments of the tropics and subtropics worldwide. In California, breeding populations were initially detected in 2013 in the cities of Fresno, Madera, and San Mateo, and now can be found in 188 cities of 12 counties in the state. Recent genetic studies suggest that this species invaded California on multiple occasions from several regions of the United States and northern Mexico prior to initial detection. As an invasive species and vector for numerous arboviruses, Ae. aegypti is a primary target of surveillance and control in California. In southern California city of Montclair, a population was identified in September 2015, from which a short-term colony was established in an insectary. The susceptibility of this field population to commonly used pesticides with various modes of action, including 15 formulations against larvae and four against adults, was determined, in reference to a susceptible laboratory colony of the same species. No resistance was shown to most pesticides tested. However, tolerance or reduced susceptibility to spinosad, spinetoram, diflubezuron, and fipronil was detected, and modest levels of resistance to pyriproxyfen (resistance ratio = 38.7-fold at IE50 and 81.5-fold at IE90) was observed. Results are discussed based on the field usage and modes of action of the pesticides tested. Strategic selection and application of pesticides against this population of Ae. aegypti in the urban environments should be taken into consideration.

Drinking and Driving in 753 General Practice and Psychiatric Patients on Psychotropic Drugs

1969 ◽  
Vol 115 (518) ◽  
pp. 99-100 ◽  
Author(s):  
Gerald Milner
Keyword(s):  
Traffic Accidents ◽  
Human Subjects ◽  
Psychiatric Patients ◽  
Chemical Agent ◽  
Drinking And Driving ◽  
Driving Skills ◽  
Psychotropic Agents ◽  
The Individual ◽  
And Control ◽  
Control Complex

Psychotropic agents are widely prescribed. The effects of a drug represent a complex interaction between the chemical agent, the individual patient and the environment in which the administration of the drug takes place. Many patients use alcohol (a C.N.S. depressant) and control complex machinery. It is necessary to know how a drug interacts with alcohol and especially how it affects driving skills. Murray (1960), in a 90 day study of 68 drivers on chlordiazepoxide, found that traffic accidents were ten times more frequent than the predicted control rate. Zirkleet al. (1959) established that chlorpromazine had “a supplementary and possible potentiating effect” on the impairment of co-ordination and judgement produced by alcohol in 24 human subjects.

scholarly journals Experimental Assessment of Zika Virus Mechanical Transmission by Aedes aegypti

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 695 ◽  
Author(s):  
Antoine Boullis ◽  
Nadège Cordel ◽  
Cécile Herrmann-Storck ◽  
Anubis Vega-Rúa
Keyword(s):  
Experimental Design ◽  
Aedes Aegypti ◽  
Zika Virus ◽  
Infectious Virus ◽  
Viral Rna ◽  
Mechanical Transmission ◽  
Experimental Assessment ◽  
Infected Blood ◽  
Virus Titration ◽  
Blood Meals

The pandemic emergence of several mosquito-borne viruses highlights the need to understand the different ways in which they can be transmitted by vectors to human hosts. In this study, we evaluated the propensity of Aedes aegypti to transmit mechanically Zika virus (ZIKV) using an experimental design. Mosquitoes were allowed to feed on ZIKV-infected blood and were then rapidly transferred to feed on ZIKV-free blood until they finished their meal. The uninfected blood meals, the mosquito abdomens, as well as the mouthparts dissected from fully and partially engorged mosquitoes were analyzed using RT-qPCR and/or virus titration. All the fully engorged mosquito abdomens were ZIKV-infected, whereas their mouthparts were all ZIKV-negative. Nonetheless, one of the partially engorged mosquitoes carried infectious particles on mouthparts. No infectious virus was found in the receiver blood meals, while viral RNA was detected in 9% of the samples (2/22). Thus, mechanical transmission of ZIKV may sporadically occur via Ae. aegypti bite. However, as the number of virions detected on mouthparts (2 particles) is not sufficient to induce infection in a naïve host, our results indicate that mechanical transmission does not impact ZIKV epidemiology.

The composition and spatial distribution of scavenging hyperbenthos in the Cape d'Aguilar Marine Reserve, Hong Kong

2011 ◽  
Vol 92 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Brian Morton ◽  
Christine N.W. Lee
Keyword(s):  
Spatial Distribution ◽  
Hong Kong ◽  
Marine Reserve ◽  
Spatial Segregation ◽  
The Other ◽  
Flow Rates ◽  
Baited Traps ◽  
Almost All ◽  
And Control

Baited traps with a 5 mm diameter opening were deployed 9 cm off the seabed in the Cape d'Aguilar Marine Reserve, Hong Kong. In contrast to analogous studies from boreal waters, lysianassoids accounted for 0.5% of the total number of trapped hyperbenthos. Species of Tisbe (Copepoda: Tisbidae), Ceradocus (Gammaridea: Melitidae), Nebalia (Leptostraca: Nebaliacea), unidentified benthic ostracods, Neanthes cricognatha (Polychaeta: Nereidae) and a species of Lepidepecreum (Amphipoda: Lysianassoidea) were caught in a decreasing order of numerical importance. A spatial segregation of trapped fauna was identified between the reserve's shallow Lobster Bay (<–2 m Chart Datum (CD)) and deeper-waters (between –6 and–17 m CD) outside it. Ceradocus sp. monopolized the trapped fauna in the former area, while the other species were caught almost exclusively from the latter. Insignificant Ceradocus sp. catch differences between baited and control traps suggested that they functioned only as ‘habitat traps’ for this species. Almost all other organisms attracted to the bait were hyperbenthic scavengers. Their absence from the shallows might be due to the coarser and lower organic contents of the sediments, also related to faster flow rates here. Finally, we confirm that in subtropical Hong Kong, lysianassid amphipods are not as significant hyperbenthic scavengers as they are in boreal waters.

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