Attractants for Rice Leaf Bug, Trigonotylus caelestialium (Kirkaldy), are Emitted from Flowering Rice Panicles

Abstract

Volatiles were extracted from rice plants of various growth stages with solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) to identify attractants that cause invasion of the rice leaf bug Trigonotylus caelestialium (Kirkaldy) into paddy fields. The composition of volatile blends produced by rice plants changed with rice development. In addition, volatile blend compositions differed between the panicles and the stems and leaves. The relative geranyl acetone content was high in all plant structures analyzed. In volatiles from whole plants in the fourth-leaf stage and panicles in the full-ripe stage, the relative content of green leaf volatiles (GLVs) was higher than that found in other rice plant structures. In contrast, relative terpene levels emitted from whole plants in the panicle-formation stage and by panicles and stems and leaves in the flowering stage were higher than those of other rice plant structures. However, the type of terpenes found differed between the panicles and the stems and leaves. Relative levels of β-caryophyllene in whole plants in the panicle-formation stage and panicles in the flowering stage were much higher than that in stems and leaves in the flowering stage. Our previous studies demonstrated that the odor from whole plants in the panicle-formation stage and panicles in the flowering stage is attractive to rice leaf bugs. Here, the attractiveness of β-caryophyllene to adult bugs was investigated in olfactometer assays. Adult females were attracted to β-caryophyllene at a concentration of 0.001%, which is approximately equivalent to the concentration produced by flowering rice panicles. However, β-caryophyllene also was present in the odor of whole plants in the fourth-leaf stage and in stems and leaves in the flowering stage. Furthermore, the amounts of this compound emitted from these structures were similar. Therefore, we suggest that the relative abundance of this compound in a volatile blend is important for attractance of the bugs.

(E)-β-caryophyllene functions as a host location signal for the rice white-backed planthopper Sogatella furcifera

“…This result was similar to that reported in Cheng et al [30]. Fujii et al revealed that during the flowering stage, rice panicles released (E)-b-caryophyllene [31]. We detected GUS activity in glumes but not stamens, implying that glumes might be the main organ for producing (E)-bcaryophyllene.…”

“…Using transformed rice plants overexpressing an (E)-b-caryophyllene synthase gene, OsCAS (namely OsTPS3), Cheng et al showed that (E)-b-caryophyllene attracts Anagrus nilaparvatae [30], an egg parasitoid of rice planthoppers. Moreover, Fujii et al found that (E)-b-caryophyllene emitted from flowering rice panicles attracts the rice leaf bug Trigonotylus caelestialium [31]. Recently, our study revealed that the constitutively produced (E)-b-caryophyllene in rice is attractive to BPH as well as to its parasitoids and predators [25].…”

“…This is probably due to stronger induced defense responses or poorer nutrient quality at the late stage in WT plants than in ir-cas lines because of higher density of WBPH on the former. In rice, (E)-b-caryophyllene has been reported to be attractive to BPH, T. caelestialium and their natural enemies [25,30,31]. In addition, (E)-b-caryophyllene in maize has also recently been proved to be an attractant for two maize pests, the root-feeder D. v. virgifera and the defoliator Spodoptera frugiperda [39], except for functioning as a crucial signal involved in indirect defense of maize plants [4,20].…”

Attraction of Lygus rugulipennis and Adelphocoris lineolatus to synthetic floral odour compounds in field experiments in Hungary

“…Behavioural response to plant volatiles have also been reported in mirid species (e.g. Fujii et al 2010), including the North American Lygus species as well (Blackmer et al 2004;Whitbey 1999). Also, for the European tarnished plant bug, it was shown in olfactometer and wind tunnel experiments, that host plant volatiles provided an important stimulus for the species (Frati et al 2008).…”

Food Preference of Pecky Rice Bugs Is Influenced by Experience

“…Both rice bug species are attracted by odors released from host plants [10]- [12] [19]. Attraction behavior is altered by olfactory learning in several phytophagous insects [20]- [24].…”