A survey of chemoreceptive responses on different mosquito appendages

Authors: YANG, LIU - University Of Florida; AGRAMONTE, NATASHA - University Of Florida; Linthicum, Kenneth - Ken; BLOOMQUIST, JEFFREY - University Of Florida

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2020
Publication Date: 8/2/2020
Citation: Yang, L., Agramonte, N., Linthicum, K., Bloomquist, J.R. 2020. A survey of chemoreceptive responses on different mosquito appendages. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjaa154.
DOI: https://doi.org/10.1093/jme/tjaa154

Interpretive Summary: Research on the ability of mosquitoes to sense chemicals have primarily focused on antennae for smell and mouthparts for taste. However, organs that sense chemicals are also present on tips of the legs and the front edge of the wing. In this study, we used instruments to detect electrical stimulations in Aedes aegypti mosquitoes when their antennae, mouthparts, legs, and wings were exposed to a variety of insect repellent and attractant compounds. The results provide evidence that the leg and wings can sense chemicals in a gaseous form, and that the odors produce differing responses on different appendages. Antennae and mouthparts showed nearly identical responses pattern to all tested compounds, and their rank orders of effectiveness were similar to those of front and middle leg tips. The Hindleg only responded to the strongest chemical, indicating that the hind legs are not as sensitive to the chemicals tested. Insights gleaned into the function of these appendages in insect detection of chemicals are discussed.

Technical Abstract: Research on the functions of insect chemoreceptors have primarily focused on antennae (olfactory receptors) and mouthparts (gustatory receptors). However, chemoreceptive sensilla are also present on other appendages, such as the leg tarsi and the anterior wing margin, and their specific roles in chemoreception and mosquito behavior remain largely unknown. In this study, electrophysiological analyses in an electroantennogram recording format were performed on Aedes aegypti (L., Diptera: Culicidae) antennae, mouthparts, tarsi, and wings during exposure to a variety of insect repellent and attractant compounds. The results provide evidence that the tarsi and wings can sense chemicals in a gaseous form, and that the odors produce differing responses on different appendages. The most consistent and strongest response occurred when exposed to triethylamine (TEA). Antennae and mouthparts showed nearly identical responses pattern to all tested compounds, and their rank orders of effectiveness were similar to those of fore- and mid-leg tarsi. Hindleg tarsi only responded to TEA, indicating that the hind legs are not as chemoreceptive. Wings responded to a range of odorants, but with a different rank order and voltage amplitude. Insights gleaned into the function of these appendages in insect chemoreception are discussed.