Olfactory and behavioral responses of red imported fire ants, solenopsis invicta to ylang ylang oil and its components

Authors: Du, Yuzhe - Cathy; ZHOU, AIMING - Huazhong Agricultural University; Chen, Jian

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2020
Publication Date: 1/27/2021
Citation: Du, Y., Zhou, A., Chen, J. 2021. Olfactory and behavioral responses of red imported fire ants, solenopsis invicta to ylang ylang oil and its components. Journal of Pest Science. https://doi.org/10.1007/s10340-020-01312-9.
DOI: https://doi.org/10.1007/s10340-020-01312-9

Interpretive Summary: The red imported fire ant is a significant invasive pest, which is inadvertently introduced into the United States from South America in the 1930s. In the United State alone, they are responsible for almost $7 billion annual loss for damage repair, medical care, and control costs. Synthetic insecticides are commonly used in controlling fire ants. Due to the concern on the negative impact of synthetic insecticides on human health and environment, more environmentally benign control products are highly desirable. Natural repellants and attractants can be useful in developing more environmentally friendly methods and products for managing fire ants. For example, repellants can be useful in excluding fire ants from some sensitive areas without using insecticides, such as hospital, school and electrical equipment; and attractants can be used to improve bait efficacy. In this study, the effect of a plant essential oil, ylang ylang oil, on fire ants were investigated. We found that ylang ylang oil elicited clear electrophysiological and behavioral responses of fine ants. Ylang ylang oil is a fire ant repellant at high concentration, but a attractant at low concentration. We identified that benzyl acetate and prenyl acetate were the key compounds responsible for those responses. These two acetate esters were attractants to fire ants at low concentrations. Discovery of these behavioral modifying compounds may open up new possibilities for developing better fire ant control products by manipulating chemosensory communication of ants.

Technical Abstract: The red imported fire ant, Solenopsis invicta Buren, is one of the most successful invasive pest ants in the world. We evaluated ylang ylang oil, an essential oil of fragrant yellow flowers of the tree, Cananga odorata, in our efforts to search attractants and repellants for S. invicta management. The results showed that ylang ylang oil elicited clear dose-dependent EAG (electroantennography) responses to ants of all castes. We performed EAG and gas chromatography-mass spectrometry (GC-MS) analysis on 70 chromatographic fractions from ylang ylang oil, revealing that S. invicta exhibited strong olfactory responses to fractions dominated by terpenes or esters. To facilitate the identification of active compounds, the fractions which covered strong EAG activity shift were subjected to GC-MS analysis. EAG analysis showed that benzyl acetate (BA) and prenyl acetate (PA) were the key compounds responsible for high EAG amplitude in male alates. In addition, ylang ylang oil, PA and BA were attractive to male and female alates in two-choice attraction bioassay and they also act as attractants at low concentrations to workers in two-choice digging bioassay. Discovery of these behavioral modifying compounds may open up new possibilities for developing better fire ant control products by manipulating chemosensory communication of ants.