Volatile fragrances associated with flowers mediate the host plant alternation of a polyphagous mirid bug

Authors: HONGSHENG, PAN - Chinese Academy Of Agricultural Sciences; YANHUI, LU - Chinese Academy Of Agricultural Sciences; CHUNLI, XIU - Chinese Academy Of Agricultural Sciences; HUIHUI, GENG - Chinese Academy Of Agricultural Sciences; XIAOMING, CAI - Tea Research Institute; XIAOLING, SUN - Tea Research Institute; YONGJUN, ZHANG - Chinese Academy Of Agricultural Sciences; WILLIAMS, LIVY, III - European Biological Control Laboratory (EBCL); WYCKHUYS, KRIS - International Institute For Tropical Agriculture; KONGMING, WU - Chinese Academy Of Agricultural Sciences

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2015
Publication Date: 10/1/2015
Citation: Hongsheng, P., Yanhui, L., Chunli, X., Huihui, G., Xiaoming, C., Xiaoling, S., Yongjun, Z., Williams, L., Wyckhuys, K.A., Kongming, W. 2015. Volatile fragrances associated with flowers mediate the host plant alternation of a polyphagous mirid bug. Scientific Reports. 14805; doi: 10.1038/srep14805.

Interpretive Summary: Plant bugs are important pests of cotton, fruit trees and many other crops in China and throughout the world. These pests usually prefer to feed on plants at the flowering stage, and therefore they tend to track plants as flowers become available. However, we do not understand the factors that govern flower preference in plant bugs. Understanding this phenomenon is important because it will lead to improved pest management decisions. We examined whether flower preference of plant bugs is mediated by host plant odors, and which odor compositions play an important role in attracting bugs. Behavioral and physiological studies with 18 different plant species showed that bugs preferred flowering plants over non-flowering plants of each species, and identified seven physiologically-active odors produced by the flowers. Four of these fragrances led to attraction in additional behavioral studies conducted in the laboratory and field settings. Our results suggest that these four plant-derived fragrant odors, which are emitted in greater amounts once plants begin to flower, mediate the bug’s preference to flowering host plants. This study provides new insights into the mechanism by which polyphagous mirid bugs locate their hosts, and could contribute to population monitoring and management strategies for these pests.

Technical Abstract: Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is an important insect pest of cotton, fruit trees and other crops in China, and exhibits a particularly broad host range. Adult A. lucorum greatly prefers host plants at the flowering stage, and their populations track flowering plants both spatially and temporally. However, the factors driving flower preference by A. lucorum remain to be investigated. In this study, we examine whether flower preference of A. lucorum adults is mediated by host plant volatiles, and which volatile compositions play an important role in attracting them. In olfactometer tests with 18 key host plant species, A. lucorum adults preferred flowering plants over non-flowering plants of each species. Coupled gas chromatography-electroantennography (GC-EAD) revealed the presence of seven electrophysiologically active compounds from flowering plants, that include (Z)-3-hexen-1-ol, m-xylene, butyl acrylate, butyl propionate, butyl butyrate, (Z)-3-hexenyl acetate and 3-ethylbenzaldehyde. Although A. lucorum adults responded to all seven synthetic plant volatiles in electroantennogram (EAG) tests, only four plant volatiles (m-xylene, butyl acrylate, butyl propionate and butyl butyrate) elicited positive behavioral responses in Y-tube olfactometer bioassays. A. lucorum adults were strongly attracted to these four active volatiles in multi-year laboratory and field trials. Our results suggest that these four plant-derived fragrant volatiles, which are emitted in greater amounts once plants begin to flower, mediate A. lucorum’s preference to flowering host plants. This study provides new insights into the mechanism by which polyphagous mirid bugs locate their hosts, and could contribute to population monitoring and management strategies for these pests.