Grapefruit-derived nootkatone potentiates GABAergic signaling and acts as a dual-action mosquito repellent and insecticide.

Humanity has long battled mosquitoes and the diseases they transmit-a struggle intensified by climate change and globalization, which have expanded mosquito ranges and the spread of associated diseases. Additionally, widespread insecticide resistance has reduced the efficacy of current control methods, necessitating new solutions. Nootkatone, a natural compound found in grapefruit, shows promise as both a mosquito repellent and an insecticide.

Genetically Encoded Calcium Indicators for Functional Imaging of Mosquito Olfactory Neurons.

Mosquitoes transmit a multitude of diseases to humans and animals through biting and blood feeding. To locate their hosts, mosquitoes primarily use their sense of smell. Therefore, an understanding of mosquito olfaction will help develop strategies to control the diseases they transmit.

Calcium Imaging of Mosquito Antennae Expressing the Calcium Indicator GCaMP6f.

Calcium imaging is a technique used to measure functional neuronal activities in response to stimuli. It has been used for years to study odorant-induced responses in insects (i.e.

Chemoreceptor co-expression in olfactory neurons.

olfactory neurons have long been thought to express only one chemosensory receptor gene family. There are two main olfactory receptor gene families in , the odorant receptors (ORs) and the ionotropic receptors (IRs). The dozens of odorant-binding receptors in each family require at least one co-receptor gene in order to function: for ORs, and , , and for IRs.

Odorant-receptor-mediated regulation of chemosensory gene expression in the malaria mosquito Anopheles gambiae.

Mosquitoes locate and approach humans based on the activity of odorant receptors (ORs) expressed on olfactory receptor neurons (ORNs). Olfactogenetic experiments in Anopheles gambiae mosquitoes revealed that the ectopic expression of an AgOR (AgOR2) in ORNs dampened the activity of the expressing neuron. This contrasts with studies in Drosophila melanogaster in which the ectopic expression of non-native ORs in ORNs confers ectopic neuronal responses without interfering with native olfactory physiology.

Olfaction in Anopheles mosquitoes.

As vectors of disease, mosquitoes are a global threat to human health. The Anopheles mosquito is the deadliest mosquito species as the insect vector of the malaria-causing parasite, which kills hundreds of thousands every year. These mosquitoes are reliant on their sense of smell (olfaction) to guide most of their behaviors, and a better understanding of Anopheles olfaction identifies opportunities for reducing the spread of malaria.

The irritant receptor TRPA1 mediates the mosquito repellent effect of catnip.

Catnip (Nepeta cataria) is a common garden herb well known for its euphoric and hallucinogenic effects on domestic cats, for its medicinal properties, as well as for its powerful repellent action on insects. Catnip extracts have been proposed as a natural alternative to synthetic insect repellents, such as N,N-diethyl-3-methylbenzamide (DEET), but how catnip triggers aversion in insects is not known. Here, we show that, both in Drosophila melanogaster flies and Aedes aegypti mosquitoes, the major mediator of catnip repellency is the widely conserved chemical irritant receptor TRPA1.

Insect repellents mediate species-specific olfactory behaviours in mosquitoes.

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.

Commonly Used Insect Repellents Hide Human Odors from Anopheles Mosquitoes.

The mode of action for most mosquito repellents is unknown. This is primarily due to the difficulty in monitoring how the mosquito olfactory system responds to repellent odors. Here, we used the Q-system of binary expression to enable activity-dependent Ca imaging in olfactory neurons of the African malaria mosquito Anopheles coluzzii.

A GAL80 Collection To Inhibit GAL4 Transgenes in Olfactory Sensory Neurons.

Fruit flies recognize hundreds of ecologically relevant odors and respond appropriately to them. The complexity, redundancy and interconnectedness of the olfactory machinery complicate efforts to pinpoint the functional contributions of any component neuron or receptor to behavior. Some contributions can only be elucidated in flies that carry multiple mutations and transgenes, but the production of such flies is currently labor-intensive and time-consuming.

Chemosensory Cues for Mosquito Oviposition Site Selection.

Gravid mosquitoes use chemosensory (olfactory, gustatory, or both) cues to select oviposition sites suitable for their offspring. In nature, these cues originate from plant infusions, microbes, mosquito immature stages, and predators. While attractants and stimulants are cues that could show the availability of food (plant infusions and microbes) and suitable conditions (the presence of conspecifics), repellents and deterrents show the risk of predation, infection with pathogens, or strong competition.

Different repellents for Aedes aegypti against blood-feeding and oviposition.

Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay.

Gravid females of the mosquito Aedes aegypti avoid oviposition on m-cresol in the presence of the deterrent isomer p-cresol.

Background: p-cresol (4-methylphenol) and its isomer m-cresol (3-methylphenol) have been shown to activate the same sensilla in Aedes aegypti (Linnaeus) mosquitoes. Whereas p-cresol has been suggested to play a role in oviposition site choice, the behavioral significance of m-cresol is unknown.

Methods: Here, we assayed the oviposition behavior of Aedes aegypti towards p-cresol and m-cresol using cage assay.

Strain specific differences in intraspecific competition in Aedes albopictus (Diptera: Culicidae).

Malathion is an organophosphate insecticide that is used for the control of adult mosquitoes and agricultural pests. Recent studies have shown that malathion affects competition among mosquitoes in the larval stage. Individuals from laboratory colonies are often used in experiments but it is not known whether there is a difference between laboratory and field strains in their response to competition and malathion.

Malathion influences competition between Aedes albopictus and Aedes japonicus.

Competitive interactions may facilitate or repel invaders into new communities, and these interactions may depend on other environmental conditions such as the presence of pesticides. Malathion is widely used in controlling agricultural pests and mosquitoes worldwide. Small amounts of malathion, previously considered inconsequential, may in fact increase in lethality when combined with biotic stressors in aquatic systems.

Growth and survival of invasive Aedes albopictus larvae on Diospyros virginiana leaves.

Studies on the interactions of exotic species with their invaded environment are imperative in understanding their invasion biology. Larvae of container mosquitoes such as the invasive Aedes albopictus (Skuse) feed on microorganisms that subsist on allochthonous inputs like leaves. Ae.