The taste of togetherness.

The larvae of fruit flies produce pheromones to control whether they are attracted to others of the same species or whether they avoid members of a different species

An Investigation Into Novel Mechanisms of Sensory Detection and Neural Processing of Repellent Odorant Information

Because of their diversity, abundance, and nigh ubiquity on land, insects represent the largest group of animal competitors to humanity. Insect vectors carry diseases such as malaria, yellow fever, and Zika that are responsible for hundreds of thousands of deaths each year, and agricultural loss to insect pests reaches billions of dollars annually. Because insects rely principally on olfactory cues to target hosts and food sources, their olfactory system is of great import for scientific study. The fruit fly Drosophila provides a genetically tractable and numerically simple nervous system well suited as a model for studying the detection and processing of odor cues. By developing in the fruit fly a technique for studying the detection of common insect repellants, we have discovered a novel mechanism of the detection of DEET involving widespread neuronal activation and inhibition, and find that this mechanism is conserved across mosquito species. We show that DEET induces either neuronal activation or inhibition in a manner dependent upon the identity of the odorant receptor expressed in the detecting neuron. A similar widespread effect is also found in response to noxious concentrations of basic amine compounds. Exposure to high concentrations of amines inhibits neurons across several sensillar classes and this inhibition renders them unresponsive to other odor ligands. We also find that certain amine compounds are able to reduce humidity sensing by the neurons in the coeloconic sensilla of Drosophila and that these compounds are able to reduce oviposition preference in mosquitoes. In summary, our research identifies several novel mechanisms of repellent detection and can potentially inform efforts in repellent development and pest management

An Investigation Into Novel Mechanisms of Sensory Detection and Neural Processing of Repellent Odorant Information

Because of their diversity, abundance, and nigh ubiquity on land, insects represent the largest group of animal competitors to humanity. Insect vectors carry diseases such as malaria, yellow fever, and Zika that are responsible for hundreds of thousands of deaths each year, and agricultural loss to insect pests reaches billions of dollars annually. Because insects rely principally on olfactory cues to target hosts and food sources, their olfactory system is of great import for scientific study. The fruit fly Drosophila provides a genetically tractable and numerically simple nervous system well suited as a model for studying the detection and processing of odor cues. By developing in the fruit fly a technique for studying the detection of common insect repellants, we have discovered a novel mechanism of the detection of DEET involving widespread neuronal activation and inhibition, and find that this mechanism is conserved across mosquito species. We show that DEET induces either neuronal activation or inhibition in a manner dependent upon the identity of the odorant receptor expressed in the detecting neuron. A similar widespread effect is also found in response to noxious concentrations of basic amine compounds. Exposure to high concentrations of amines inhibits neurons across several sensillar classes and this inhibition renders them unresponsive to other odor ligands. We also find that certain amine compounds are able to reduce humidity sensing by the neurons in the coeloconic sensilla of Drosophila and that these compounds are able to reduce oviposition preference in mosquitoes. In summary, our research identifies several novel mechanisms of repellent detection and can potentially inform efforts in repellent development and pest management

The taste of togetherness.

The larvae of fruit flies produce pheromones to control whether they are attracted to others of the same species or whether they avoid members of a different species

Pentylamine inhibits humidity detection in insect vectors of human and plant borne pathogens.

Insects house humidity-sensing neurons in the antenna, which is presumed to be important for a variety of behaviors and survival since water is a crucial component of the environment. Here we use the simple olfactory system of the Asian Citrus Psyllid (ACP), a citrus pest that transmits a deadly bacterium, to identify volatile amines that significantly inhibited humidity-induced activation of antennal neurons. The inhibition of action potentials is observed by single sensillum recordings and mixing these odorants with humid air abolished the humidity avoidance behavior of ACP. The inhibition is conserved in the humidity-sensing coeloconic neurons of dipteran Drosophila melanogaster that are known to detect humidity, but it is not seen in other coeloconic neurons that are not sensitive to humidity. Dipteran mosquitoes Aedes aegypti and Anopheles gambiae oviposit in water, and the addition of the humidity-inhibiting odorants in a two-choice oviposition assay significantly reduces oviposition. Our results demonstrate that a naturally occurring volatile compound can effectively "mask" detection of an important environmental cue and modify behavior of important vectors of plant and human disease pathogens. Odorants targeting the conserved humidity sensing system of insects, therefore, offer a novel strategy for modifying their behavior

Chemosensory detection of aversive concentrations of ammonia and basic volatile amines in insects

Basic volatiles like ammonia are found in insect environments, and at high concentrations cause an atypical action potential burst, followed by inhibition in multiple classes of olfactory receptor neurons (ORNs) in Drosophila melanogaster. During the period of inhibition, ORNs are unable to fire action potentials to their ligands but continue to display receptor potentials. An increase in calcium is also observed in antennal cells of Drosophila and Aedes aegypti. In the gustatory system, ammonia inhibits sugar and salt responses in a dose-dependent manner. Other amines show similar effects in both gustatory and olfactory neurons, correlated with basicity. The concentrations that inhibit neurons reduce proboscis extension to sucrose in Drosophila. In Aedes, a brief exposure to volatile ammonia abolishes attraction to human skin odor for several minutes. These findings reveal an effect that prevents detection of attractive ligands in the olfactory and gustatory systems and has potential in insect control

Chemosensory detection of aversive concentrations of ammonia and basic volatile amines in insects

Summary: Basic volatiles like ammonia are found in insect environments, and at high concentrations cause an atypical action potential burst, followed by inhibition in multiple classes of olfactory receptor neurons (ORNs) in Drosophila melanogaster. During the period of inhibition, ORNs are unable to fire action potentials to their ligands but continue to display receptor potentials. An increase in calcium is also observed in antennal cells of Drosophila and Aedes aegypti. In the gustatory system, ammonia inhibits sugar and salt responses in a dose-dependent manner. Other amines show similar effects in both gustatory and olfactory neurons, correlated with basicity. The concentrations that inhibit neurons reduce proboscis extension to sucrose in Drosophila. In Aedes, a brief exposure to volatile ammonia abolishes attraction to human skin odor for several minutes. These findings reveal an effect that prevents detection of attractive ligands in the olfactory and gustatory systems and has potential in insect control