Insect antennae play important roles in finding mates and in locating food source and oviposition sites. Riptortus pedestris is an important pest of soybean and sweet persimmon in Korea. The male R. pedestris adult produce the aggregation pheromone attracting the conspecific nymphs and both sexes of adults. The pheromone was known as a cue for food finding, but the 1st instar nymph can develop to the 2nd instar without food. This phenomenon may suggest that the 1st instar nymph may have different sensilla system from other instars. Thus, we investigated the morphology and distribution of antennal sensilla and antennal response to the aggregation pheromone (AG) of each nymphal stage using Scanning Electron Microscope (SEM) and Electroantennography (EAG). As expected, first instar nymph did not have sensilla trichodea 3 (T3) and chaetica 3 (Ch3) which existed in other instar nymphs. The antennae of the 1st instar nymph did not responded to AG, with no difference from control. For further elucidation of the functions of sensilla T3 and CH3, single sensillum recording to AG will be done.

This study was performed to investigate attraction effect of spearmint oil and to confirm their EAG response against lantern fly, Lycorma delicatula nymphs and adult. In dose responses to spearmint oil, 2nd ∼ 4th nymphs and adult were significantly attracted at a dose of 5㎕. Attraction effect was showed highest (84.8%) at a 4th instar nymph, and mild effect (approximately 60%) was observed at 2nd∼3rd instar nymphs, but the others are not showed the significance. At a dose of 10㎕, 4th instar nymph and adult were significant and only 4th instar nymph was significantly attracted at a dose of 2.5㎕ but the others are not. Carvone, a constituent of spearmint oil, exhibited significantly attraction effect on nymphs and adult except 1st and 2nd instar nymphs. But limonene did not show any attraction effect. The attraction assay of L. delicatula to the mixtures of constituents appeared to be efficient additively. In EAG response to spearmint oil which exhibited attraction effect, antennae of 4th instar nymph and adult responded to only carvone. In conclusion, attraction effect of spearmint oil was more effective in 4th instar nymph and adult than 1st ∼ 3rd instar nymphs.