Sebum Production as a Possible Indicator of Key Odorant Concentrations and Host Odor Preference in Aedes Aegypti Mosquitoes

Abstract

On the list of significant threats to humans, mosquitoes certainly top the list. The Aedes aegypti mosquito has caused immense human suffering throughout history by spreading yellow fever, dengue, chikungunya, and Zika. As an individual’s health does not exist in a vacuum but is continuously impacted by other humans, non-human organisms, and the environment, studying multiple disciplines are necessary to maximize positive health outcomes. Mosquitoes must have a way of finding their hosts, but understanding these mechanisms is currently one of the leading questions in the field. The volatile organic compounds (VOCs) that make up human odor are a major cue in host seeking and distinguishing, and thus identifying the key compounds are of utmost importance. Recent findings show that the olfactory receptor neurons (ORNs) are particularly sensitive to certain odorants in sebum (but not limited to): sulcatone, geranylacetone, decanal, nonanal, hexanal, and octanal. Here, the question of how sebum output relates to the concentrations of these key compounds was explored. A total of 54 participants had their sebum output measured using Sebutape and those with low or high sebum outputs were identified. Nine participants then had their odor extracted and analyzed through gas chromatography–mass spectrometry (GC-MS). Their GC-MS chromatogram was then used to quantify the six key compounds. Of these key compounds, sebum levels were most associated with geranylacetone concentrations (p=0.049), with sulcatone and decanal following behind but non-significantly (p=0.165, p=0.160). The overall concentration of these key compounds was found to increase with increasing sebum output. This finding suggests that sebum production can be a proxy for concentration of key odorants and thus possibly an efficient way to assess individual attractiveness. Future investigations using behavioral assays should be conducted to further determine if sebum output can become a key indicator for attractiveness.