Harlequin ladybird (Harmonia axyridis (Pallas, 1773)) is an invasive species originating from Asia, posing a potential threat to the ecosystem and the wine industry in New Zealand due to wine taint, although it can also be a useful biocontrol agent. In this study, the response profiles of antennal olfactory receptor neurons (ORNs) to 32 plant volatiles were examined in male and female H. axyridis, using the single sensillum recording technique. Various types of ORNs were identified from four types of olfactory sensilla in both male and female H. axyridis, with no sexual dimorphism. The most abundant type of sensilla contained two ORNs exhibiting highly specialized responses to methyl benzoate and β-caryophyllene, respectively. Another type of sensilla also contained two specialized ORNs, one responsive to geranyl acetate and the other to some aromatic compounds such as 2-phenylethanol, benzyl acetate, methyl benzoate, and methyl phenylacetate. In contrast, two other types of sensilla contained broadly tuned ORNs, one containing ORN(s) responsive to six-carbon alcohols such as (Z)-3-hexen-1-ol, 1-hexanol, and isomers of 2-hexen-1-ol as well as some other non-alcohol green leaf volatiles, and the other containing ORN(s) exhibiting responses to β-myrcene, geraniol, linalool, nerol, benzyl acetate, and methyl phenylacetate. This study suggests that H. axyridis possesses a set of ORNs specialized for specific plant volatiles, providing insights into the olfactory communication system of this species and potential volatiles to be used for trapping this insect.

Spodoptera 속의 담배거세미나방, 열대거세미나방 및 파밤나방은 여러 나라에 분포하는 광식성 해충으로, 본 연구에서는 이들의 페로몬 및 식물냄새물질과 관련한 화학통신시스템에 대해 이해하기 위해 냄새감각기의 종류와 분포, 냄새활성물질 동정 및 야외행동 반응에 대한 연구를 진행하였다. 주사전자현미경 관찰을 통해, 세 종 나방의 암, 수컷 촉각에 여러 종류의 냄새감각기가 존재하며, 형태적으로 구분되는 종특이적 또는 성특이적 냄새감각기들이 존재한다는 것을 확인하였다. GC-EAD 실험을 통해 세 종 나방에 냄새활성을 나타내는 식물 냄새물질과 페로몬 관련 물질들을 동정하고, 이들을 개별 또는 조합하여 야외 트랩실험을 통해 행동활성을 검정 한 결과, 이 중 여러 물질이 담배거세미나방과 파밤나방의 성페로몬에 대한 유인행동 반응을 저해하는 것을 알 수 있었다. 열대거세미나방은 발생이 저조하여 야외에서의 행동반응을 확인할 수 없었다.

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.

담배거세미나방(Spodoptera litura), 열대거세미나방(Spodoptera frugiperda) 및 파밤나방(Spodoptera exigua) 은 광식성 해충이지만, 종특이적인 기주범위를 갖는다. 이들이 기주식물을 찾아가는 과정에 냄새감각이 어떤 역할을 하는지 알아보기 위해, 기주 및 비기주 식물에서 발산되는 46가지 휘발성 물질을 선정하여, 이들에 대한 나방 3종의 냄새반응을 GC-EAD(gas chromatography-electroantennogram detection)를 통해 확인하였다. 그 결과, 46가지의 식물유래화합물 중 9가지 물질이 3종의 나방 모두에서 냄새활성을 나타냈으며, 2가지 물질은 담배거세 미나방과 열대거세미나방에만 냄새활성을 나타냈고, 다른 몇 가지 물질은 담배거세미나방에만 냄새활성을 나 타냈다. 이 결과는 세 종 나방이 식물냄새물질 탐지를 위해 유사한 냄새감각세포를 가지며, 일부 종에서는 종특이 적인 냄새감각세포가 존재한다는 것을 보여준다. 이 결과를 바탕으로 냄새활성을 나타낸 물질들의 나방 3종에 대한 행동활성을 야외트랩실험을 통해 확인할 예정이다.

호박꽃과실파리(Bactrocera scutellata)는 박과 식물의 해충으로 기주식물을 찾아가는데 냄새 감각이 중요한 역할을 한다. 이들의 기주 식물인 단호박, 애호박, 노란호박 및 하늘타리의 냄새물질을 포집하여 이들 추출물에 대한 호박꽃과 실파리의 촉각과 작은턱수염의 냄새반응을 GC-EAD(Gas chromatography-electroantennographic detection) 및 GC-EPD (Gas chromatography-electropalpographic detection)를 이용하여 조사한 결과, 촉각과 작은턱수염에 존재하는 냄새감각세 포들에 강한 냄새활성을 나타내는 여러 물질들이 탐지되어, 촉각과 작은턱수염 모두 기주식물의 감지에 중요한 역할을 한다는 것을 보여주었다. 하지만, 촉각과 작은턱수염에 냄새활성을 나타내는 물질들의 종류는 서로 확연한 차이를 보여서 촉각과 작은턱수염이 기주식물의 냄새물질 탐지에 서로 다른 역할을 할 것이라는 사실을 나타내었다. 우리는 이들 냄새활성물질의 화학구조 동정을 진행하고 있으며, 이들의 구조가 밝혀지면 이들 물질의 호박꽃과실파리 에 대한 행동활성을 조사할 예정이다.

호박꽃과실파리, Bactrocera scutellata (Hendel) (Diptera: Tephritidae),는 호박 등 박과식물의 해충으로 야외 트랩실험을 통해 호박꽃과실파리 수컷이 cue lure와 raspberry ketone에 유인되는 것이 확인되었으며, 전자현미경 관찰을 통해 호박꽃과실파리의 촉각(antennae)과 작은턱수염(maxillary palps)에 각각 다른 형태의 냄새감각기들이 존재한다는 것을 확인하였다. 이 결과를 바탕으로 Bactrocera 속 과실파리들의 parapheromone 성분들인 cue lure, raspberry ketone, methyl eugenol, 및 zingerone 등의 물질들이 촉각과 작은턱수염 중 어떤 감각기관에 의해 감지되는지 알아보기 위해 이 물질들과 식물 냄새성분인 3-octanone에 대한 호박꽃과실파리의 eleltroantennogram (EAG) 및 electropalpogram (EPG) 반응을 측정하였다. 그 결과 cue lure 및 raspberry ketone은 작은턱수염에서 큰 EPG 반응을 보였으나 촉각에서는 EAG 반응을 나타내지 않았다. 이와는 대조적으로 호박꽃과실파리의 기주식물인 호박에서 방출되는 냄새 성분 중 하나인 3-octanone은 촉각에서 큰 EAG 반응을 나타내었으나 작은턱수염에서는 아주 작은 EPG 반응만을 나타내었다. 이러한 결과는 호박꽃과 실파리 수컷에 강한 유인력을 나타내는 cue lure와 raspberry ketone이 촉각이 아니라 작은턱수염에 존재하는 냄새감각세포들에 의해 감지된다는 것을 의미하며 이것은 호박과실파리 등 아직 강력한 유인제가 알려져 있지 않은 다른 과실파리류의 유인제 개발에 유용한 정보가 될 것이다.

Monitoring is an important component in the detection, surveillance and eradication of invasive insect pests. In particular, the availability of useful attractants and effective traps is critical in establishing a new surveillance program for quarantine pests. A powerful, species-specific attractant is desirable when precision early detection is needed. However, such an ideal attractant is not often available when the introduction of a new surveillance program is urgent. In reality, the combination of available monitoring means is adopted, which in turn requires the subsequent development of optimum monitoring strategy with these available means. Various species of fruit flies, belonging to the genus Bactrocera in particular, are serious threat to Korea, and developing systematic monitoring systems is needed against the invasion of the fruit flies. Effective male attractants, such as methyl eugenol and cue lure, and traps are currently available for some species such as B. dorsalis, B. tryoni, and B. carambolae. However, such attractants are yet to be developed for many other fruit fly species. The strong attraction of the striped fruit fly, B. scutellata, being present in large numbers in Korean fields to cue lure can be a potential obstacle in monitoring other species of fruit flies attracted to the same compound. Various attractants based on protein hydrolysates are also useful in monitoring fruit flies since they are attractive to both males and females of fruit flies. However, it is desirable to develop these protein-based baits into more species-specific attractants. Monitoring techniques for some important quarantine fruit flies are further discussed.

This experiment was carried out to investigate the effect of harvesting time of Italian ryegrass (Lolium multiflorum Lam; IRG) in spring on dry matter (DM) yield. IRG cultivars ‘Kowinearly’ and ‘Greenfarm’ were seeded at 50 kg/ha and grown on rice paddy fields. There was no difference in growth characteristics between both varieties before winter. However, cold tolerance of Kowinearly was higher than that of Greenfarm, as demonstrated by post-wintering growth characteristics. The heading date of both varieties was affected by the spring weather. The IRG was harvested three times at 5-day intervals beginning from 9 May. The DM yield of Greenfarm was 6,306; 7,335; and 8,109 kg/ha, and that of Kowinearly was 7,498; 9,196; and 10,449 kg/ha at the three consecutive harvests. The delay of the harvesting time for 5 and 10 days increased the DM yield of Greenfarm by 16% and 29% and that of Kowinearly by 23% and 39%, respectively, compared to the yield at first harvest (p < 0.05). Therefore, IRG harvest later than early to mid-May is expected to increase productivity. The feed values of Greenfarm were: 12.2% of crude protein (CP), 34.5% of acid detergent fiber (ADF), 57.7% of neutral detergent fiber (NDF), 61.6% of total digestible nutrients (TDN), and 72.3% of in vitro DM digestibility (IVDMD). For Kowinearly, these values were 16.4% of CP, 30.4% of ADF, 52.7% of NDF, 64.9% of TDN and 79.0% of IVDMD.

The present study investigated the effects of different seeding rates on growth characteristics and seed productivity of the “Kowinearly” cultivar of Italian ryegrass (Lolium multiflorum Lam.) in paddy fields. Sowing Kowinearly in paddy fields under growing rice at the rates of 20, 30, 40, and 50 kg/ha resulted in seed yields of 1.57, 1.92, 2.06, and 2.09 ton/ha, respectively. Seed yield of Kowinearly was the highest at a seeding rate of 50 kg/ha (p<0.05), at which the cultivar was able to survive in winter and the weed ratio was low. Under these conditions, most growth characteristics such as winter survival (85%), weed ratio (10%), stems per square meter (1,006) were superior than those sown at other seeding rates (p<0.05). In addition, it has been reported that the economic efficiency of the 50 kg/ha seeding rate was higher than that of the other seeding rates.

Electrophysiological responses of Queensland fruit fly, Bacterocera tryoni, were investigated to identify the olfactory receptor neurons (ORN) in the antennae and corresponding active volatile compounds, using the single sensillum recording technique and 52 test compounds including methyl methyl eugenol, cuelure and raspberry ketone. We found that different classes of olfactory sensilla and ORNs are present in the antennae of B. tryoni. Most of the ORNs appeared to have narrow response spectra, exhibiting specialized responses to one or a few volatile compounds among the 52 compounds tested. In this study, ORNs specialized for ammonia, nonanal, isopentanol, ethyl acetate, indole, phenol, 2,5-dimethylpyrazine and 2-coumaranone, respectively, have been identified. A class of ORNs exhibited highly specialized responses to methyl eugenol. A preliminary field trapping test conducted in New Caledonia to evaluate the behavioral activities of the olfactory active compounds indicated a blend of three synthetic compounds is attractive to female B. tryoni.

Four sympatric tortricid (Lepidoptera) species in New Zealand, Epiphyas postvittana (Walker), Planotortrix octo (Dugdale), Cydia pomonella (L.), and Cydia succedana (Denis and Schiffermüller), were studied for the morphology of antennal sensilla and the chemical communication systems using scanning electron microscopy (SEM), electro-antennogram (EAG), gas chromatography-electroantenno-detection (GC-EAD), single sensillum recording (SSR) and field tests. Antennal flagella of adult have four main types of olfactory sensilla (s.); s. trichodea, s. basiconica, s. auricillica, and s. coeloconica in the four species. The s. trichodea subtype I was longest and male-specific in all the species. The antennae of males of the four species showed characteristic higher EAG, GC-EAD and SSR responses to 12, 14-carbon acetates or alcohol. Some of the selected chemicals selected from the electrophysiological experiments caused significant antagonistic or agonistic activities to the sex pheromone of each species in the field. In this study, the four species showed distinct chemical communication systems according to sub-family, which possibly serve as a factor in species isolation.