Sensory electrophysiological recording techniques such as EAG (electroantennogram), GCEAD (coupled gas chromatograph-electroantennogram detection) and SSR (single sensillum recording) have been useful in the chemical ecology studies of insects and plants. Numerous pheromones and other semiochemicals have been identified through GCEAD analysis, and the response profiles of antennae and individual olfactory receptor neurons have been characterized by using EAG and SSR techniques. In this talk, the practical aspects of these techniques are presented in detail. Standard setup and procedure of each electrophysiological recording technique, and important parameters and proper data analysis methods will be introduced as well as its applications. Common mistakes and limitations of these techniques will also be discussed.

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.

20 Hz 이하의 저주파 음은 해충 및 생물에게 스트레스를 발생시킬 수 있는 유해한 음으로 알려져 있다. 본 연구에서는 아메리카잎굴파리에 대한 저주파 음의 스트레스 효과를 조사하기 위하여 앰프 및 스피커(13 인치, 200 W)를 이용하여 사인파 20~1,000 Hz 구간의 순음을 절제된 아메리카잎굴파리 머리에 노출시켜 EAG 반응을 조사한 결과, 20 Hz 이하의 저주파 음에서만 EAG 반응이 나타났다. 또한 20 Hz 사인파 순음을 6시간 동안 조사하여 아메리카잎굴파리의 행동변화를 조사하였다. 행동 자료를 정보 엔트로피를 통해 분석한 결과, 엔트로피 지수는 처리 전의 경우 1.86이었으나 저주파 음을 처리한 후에는 1.42로 감소하였다. 본 연구를 통해 높은 음압의 저주파 음은 아메리카잎굴파리 방제에 활용할 수 있을 것으로 예상된다.

파리목 곤충의 청각기관은 더듬이의 존스턴 기관으로 알려져 있어, 소리에 대한 아메리카잎굴파리 더듬이의 반응을 EAG를 이용하여 조사하였다. 순음(사인파)과 아메리카잎굴파리 및 다른 3종의 구애노래를 절제된 아메리카잎굴파리 머리에 노 출시키고 EAG를 통하여 반응을 관찰하였다. 순음의 경우 20 Hz의 저주파에서만 EAG 반응이 관찰되었다. 구애노래의 경우 검정발노랑굴파리(Cryptonevra inquilina) 와 일본의 Lipara japonica 구애노래에 대한 반응이 나타났으나 아메리카잎굴파 리 수컷의 구애노래에 대한 암컷의 EAG 반응은 나타나지 않았다. 조사된 음파에 대한 반응행동을 관찰하기 위해 2차원 궤적 추적을 추가적으로 실행하였다. 기록 된 궤적은 x축 궤적의 평균값을 비교하여 소리에 대한 유인효과를 조사하였고, 궤 적의 정보 엔트로피를 이용하여 활동성 차이를 분석하였다. x축 평균값은 소리에 대한 차이가 없어, 소리에 대한 아메리카잎굴파리의 유인효과는 관찰하지 못 하였 다. 처녀 수컷과 암컷, 교미한 수컷에서는 소리를 노출시켰을 때 정보 엔트로피 값 이 감소하여 활동성이 차이가 남을 알 수 있었으나 교미한 암컷에서는 활동성의 차이가 없었다.

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.

The EAG (Electroantennogram) has been used to find out chemical substance effective to insect. We tried to use EAG recording for catching of responsible acoustic signals to Lirimyza trifolii (Diptera: Agromizidae). In fly auditory organ known as Johnston's organ located on antenna. Pure tone sounds (sine wave) and courtship songs of several kinds of species were broadcasted to excised head of the fly. Significant EAG signals were detected when released the 20 Hz pure tone sound and long pulse train patterns, which were courtship songs of Cryptonevra inquilina and Lipara japonica (Chloropidae). For conformation of it's effectiveness, we further analyzed movement behavior with the signal got from the EAG recording. Information entropy could represent the specimens activities of movement tracks. The entropy with sound was relatively lower than without sound. The combination of EAG responding and behavioral observation would be useful to analyze the response of insect pest against acoustic signals and develop acoustic pest managing tool in agriculture.