Research Center for Endangered Species in National Institute of Ecology was recently established in Yeongyang, Gyeongsangbuk-do on October 2018. As a new research center, we are actively developing research projects even though we have lots of hurdles. Among 26 endangered insect species, five species have been focused as restoring insect. Recently, the focus of restoration strategy was changed from species to habitat. To protect the insects from extinction, we will conserve the original habitat and cooperate with the local community. As a starting research center, we are open to all of your opinion to restore endangered insects in Korea.

Modern technique development provides a new opportunity to expand entomological researches. Aerial insect sampling has been conducted with fixed-wing unmanned aerial vehicles (UAVs). With improved maneuverability, rotary-wing UAVs can serve as more convenient and feasible tools with lower cost. A rotary-wing UAV with remotely controlled insect nets was developed to collect insects at designated altitudes above the rice field (ca. 80 × 240 meter (width × length)) in Boryeong, South Korea. From 21 flights in June, July, and August 2017, 235, 7, 6, and 3 insects were caught at 5, 10, 50, and 100 meters above the rice field, respectively. The collected insects were identified to family level. Diptera (Phoridae and Chironomidae), Hemiptera (Aphididae and Delphacidae), and Thysanoptera were found from the sample, some of which may contain possible insect pests on rice. Therefore, UAVs have potential as an alternative aerial insect sampling method.

Haemaphysalis longicornis (Acari: Ixodidae) is a medically important arthropod vector of tick-borne diseases, especially the severe fever with thrombocytopenia syndrome (SFTS). To establish a management strategy against tick-borne diseases, it is fundamental to understand the basic biology of vector species. Therefore under laboratory conditions, we evaluated the horizontal movement of adult and nymph stages of H. longicornis to better understand their dispersal behaviors. In the experiments, field populations were subjected to video recording of the horizontal movement of the ticks in a petri-dish arena for 3 hours. Our results indicate that nymphs showed a significantly higher mobility than adults, whereas there was no significant difference in angular velocity. Nymphs moved 3.74 ± 0.26 m at an angular velocity (AV) of 1.60 ± 0.07 deg/s. and adults moved 2.91 ± 0.26 m at an AV of 1.61 ± 0.14 deg/s.

Seasonal distribution of disease vector species including mosquitoes and ticks plays a key role in establishing risk managementof vector-borne disease. However, environmental factors affecting abundance and distribution of vector species are notcurrently well understood. Therefore, we conducted a two-year field sampling to address the population dynamics of mosquitoesand ticks in Gyeonggi-do in 2015 and 2016. In 2015, the population density was highest in May for ticks (e.g. Haemaphysalislongicornis) and June for mosquitoes (e.g. Aedes vexans), whereas both pest groups peaked in August in 2016. Culexpipens (82.3% Species Ratio), Ae. vexans (77.3% SR), and Anopheles sinesis sp. (45.3% SR) were the most dominantspecies in urban area, cow shed and wild bird refuge, respectively. For ticks, H. longicornis (47.7% SR) was the mostdominant throughout four potential habitats.

Different types of insect-borne plant viruses can modify their hosts and vectors in distinct manners. Therefore, interactionsbetween two types of viruses co-existing in a field are known to be complex to predict. Obtaining empirical data byconducting field experiments, however, requires numerous biotic and abiotic factors to be controlled, and is therefore hardto execute. Thus, we designed an individual based model to simulate the transmission pattern of two viruses, using potatoes(Solanum tuberosum) for host plant, aphids (Myzus persicae) for virus vector, potato leafroll virus and potato virus Yfor different types of plant viruses. More specifically, we aimed to investigate the effect of the following on the spreadof the plant viruses: dispersal by winged-form aphids, initial number of virus-infected seed potatoes, and indirect interactionsbetween two viruses by affecting life traits of the vectors.

Vertical transmission of symbiont is known as the most effective way to deliver their offspring. However, it has beenreported that the bean bug, Riptortus pedestris, acquires its gut symbiont, Burkholderia sp., from its environment (e.g.soil) during the 2nd instar nymphal stage. Nevertheless, it is not unknown how they locate their symbiont. For this reason,dual-choice experiments were conducted in both solitary (a nymph) and group conditions (100 nymphs) to investigatewhether or not R. pedestris has preference on Burkholderia sp. treated or untreated solution in laboratory conditions. Inthese experiments, there was no significant difference in the preference between the two treatments. We are testing inthe Y-tube olfactometer system to evaluate the response of R. pedestris on possible chemical cues from Burkholderia sp..

The bean bug, Riptortus pedestris, is a pest of leguminous crops. Recent studies have revealed an interesting relationship between R. pedestris and a gut symbiont Burkholderia sp.. R. pedestris mainly acquires Burkholderia sp. during 2nd instar period, which leads to enhancement of growth and reproductive rate of the host. Nevertheless, how R. pedestris acquires its symbiont is not yet clearly described. Therefore, we investigated whether 2nd instar nymphs have preference on Burkholderia sp. compared to untreated control in laboratory settings. In the choice test, no significant difference was found in the preference by R. pedestris between the two treatments. To further investigate single individual’s behaviors (its first choice, approaching frequency to each treatment, and residence time on the treatment). We video-recorded single individuals in the choice setting for 12 hours. Again, there was no significant difference in any of the behavioral traits recorded. Further choice tests will be conducted in the Y-tube olfactometer systems and semi-field conditions.

The bean bug, Riptortus pedestris (Hemiptera: Alydidae), is one of the major pests on leguminous crops especially in Korea and Japan. Because of its economic importance as crop pest, A large proportion of research on this species have focused on applied questions related to pest management tactics. In addition to the applied research, recent studies have also revealed an interesting relationship between R. pedestris and a gut symbiont Burkholderia sp. as an ideal model system for insect-microbe symbiotic interaction. Under this circumstance, our research group initiated a series of research projects to better understand behavioral ecology of R. pedestris and address its implications for both basic and applied questions. This presentation will cover various behavioral studies with R. pedestris including sublethal effects of insecticides, harmonic radar tracking, overwintering ecology, and symbiont acquisition mechanisms

Plant virus can enhance its transmission by altering the settling preference of its vector. Nevertheless, most of the studies have focused on the spread of one virus in a field whereas often times there are more than single virus infecting same crop. Furthermore, mixed-infection of multiple viruses tends to cause more severe virus symptoms and changes vector’s biology and behavior different than singular infection. Thus, we are currently investigating the spatial transmission pattern of persistently transmitted potato leafroll virus and non-persistently transmitted potato virus y. However, due to impracticability of obtaining empirical data, we are programming an individual-based modelling software while taking biology of potato, biology and behavior of aphid and different characteristics of two viruses into consideration.

An insect is a ectothermal animal that is vulnerable to the temperature change. As climate change accelerated, the distribution of insects have been rapidly changed. Rice is the most important crop in Korea as it is a staple for Korean people. In the rice paddy, migratory pests from south-east Asia have seriously damaged on the crop. As climate changed, the spatial distribution of pest and their effects on rice paddy may be changed. Therefore, monitoring the pest populations is a basis for establishing further research for pest management strategy against these migratory insect pests. As the first year for this monitoring project, we set 20 rice paddies in Gyeonggi-do and Chungcheongnam-do as continuous monitoring sites for five major migratory pests and summarized the first year’s data. Based on it, we will develop better monitoring plan as well as analysis methods.

It is not uncommon in the nature for insects to have symbiotic relationships with microorganisms. The bean bug, Riptortus pedestris, which harbors symbiont Burkholderia sp., is a serious agricultural pest in South Korea and Japan. It is reported that the symbiont has positive effects on the fitness of R. pedestris. However, virtually no information is available for how this insect finds the symbiont in the nature and how the behavior of R. pedestris is affected by the symbiont. To investigate the symbiont acquisition mechanism, the frequencies of R. pedestris approaching to symbiont or untreated control treatment were compared in a plastic cage (465×290×260mm) (n=20). In the experiment, there was no detectable difference between the two treatments. Further study using video tracking systems will help us to better understand detailed behaviors for symbiont acquisition.

Distillers dried grain (DDG) and makgeolli spent grain (MSG) are agricultural by-product to produce alcoholic beverage. However, they are known to contain enough nutrients. Mealworm is a promising insect resource for an animal feed ingredient as well as alternative human food. With low cost, DDG and MSG were investigated as a feed ingredient for rearing high quality mealworms. DDG and MSG were mixed with wheat bran and compared to control feed (only wheat bran) for its effects on larval survivorship, larval weight, duration for larval development, pupation rate, and pupal weight. Adding DDG on wheat bran showed positive results for larval weight, duration for larval developmental period, and pupation rate. However, adding MSG made longer duration for larval development, but it also improved larval weight, pupal weight with more than 90% pupation rate. We confirmed that adding 30～50% of DDG or MSG to conventional wheat bran have a strong potential to replace the conventional wheat bran insect feed for quality insect production.

The bean bug, Riptortus pedestris (Hemiptera: Alydidae), is a major pest of soybean and tree fruit in Korea. To protect crops, chemical insecticides have been widely used. However, the effects of insecticides is not only reduce the pest population but also change of pest behavior. In this study, we tested the effects of two insecticides, etofenprox (pyrethroid) and acetamiprid (neonicotinoid), on the behavior of R. pedestris. Two insecticides were diluted with water based on the conventional spray dose. After exposed to insecticide residue, adult R. pedestris was put individually into a clean petri dish with soybean. The behavior of R. pedestris was video-recorded for 16 hours. The frequencies of approaching to food and feeding were compared to the untreated control group. R. pedestris exposed to etofenprox made more frequent approaching to the food, but those exposed to acetamiprid made less frequent approaching compared to the control group. When compared to the control group, the feeding frequency of acetamiprid-exposed group was significantly reduced but etofenprox-exposed group showed more frequent feeding activity. In both treatments, the feeding probability, calculated by feeding frequency divided by approaching frequency, was reduced compared to the control. We conclude that acetamiprid may protect crops by reducing the frequency of R. pedestris to approach and feed on crops.

Various techniques have been developed to monitor insect behavior in the field. Harmonic radar tagging is a promising method of tracking target insects because it can allow efficient detection of the insects with negligible effects on their behavior or physiology. However, availability of the light limits the effectiveness of the method as it is almost impossible to spot an insect in the dark. On the other hand, fluorescent-marking, when combined with strong light source, makes the organisms distinct at night in a non-destructive manner. Therefore, we conducted a field experiment to determine the effectiveness of the combination of the two methods. Riptortus pedestris (Fabricius) adults were marked with both harmonic radars and fluorescent paint. The marked insects were haphazardly arranged and pinned onto trees or the ground in the forest at night. Then, a group of paired researchers, one equipped with a harmonic radar and the other with a hand-held laser, attempted to find R. pedestris within 20 minutes. The detection rate showed a high variance ranging from 40% to 100%. Thus, with a proper training, harmonic radar system combined with fluorescent-marking can be a powerful technique to detect insects in the field. With these equipments, tracking insect behavior in the field will be more efficient in the dark.

Temperature as a major environmental factor affects on organisms on various levels including molecular, physiological, behavioral and ecological levels. Transient receptor potential channels (TRPs) are a cation channel family. Among them, thermo-TRPs are known as a thermosensor. The potential role of thermo-TRPs have been identified in the fruit fly, Drosophila melanogaster, in thermotaxis and in thermal acclimation. With RNA interference (RNAi) technique, the role of thermo-TRPs in the red flour beetle, Tribolium castaneum, was identified by measuring thermal avoidance behavior in a behavioral assay. RNAi of trpA1 reduced high temperature avoidance, 39 and 42 °C. Moreover, the effects of RNAi of thermo-TRPs on the heat-induced knockout and the death after short exposure to high temperature was measured after one minute exposure at 52 °C, either with or without a 42 °C 10-minute thermal acclimation period. Even though it was relatively short time exposure to high temperature, it was enough to induce high temperature thermal acclimation. RNAi of trpA1 made faster knockout at 52 °C. With RNAi of painless, the recovery rates from heat-induced knockout after thermal acclimation. RNAi of pyrexia reduced long-term total survivorship without thermal acclimation.

Riptortus pedestris is a major agricultural pest in Korea. To manage this pest, it is necessary to understand the complete life history of R. pedestris. However, most studies have focused on the summer period when the pest attacks crops. Therefore, we conducted laboratory and field experiment to identify overwintering behavior of adult R. pedestris. First, we conducted two laboratory experiments to examine overwintering habitat preferences and spatial distribution of R. pedestris in the habitat. Second, we conducted field survey to characterize overwintering sites of R. pedestris in diverse landscapes. In the laboratory conditions, R. pedestris almost exclusively showed overwintering behavior in the leaf litter arena (63%) among the structures tested (rocks: 3%; rotten wood: 0%). And spatial distribution of R. pedestris showed solitary behavior in leaf litters. In the field, we located 12 individuals of overwintering adults from the urban areas, whereas no individuals were found from the high-elevation mountains and agricultural landscapes. Our results suggest that R. pedestris mainly use leaf litter as an overwintering structure, with solitary behavior, and low-elevation forested areas near urban landscapes seem to be more preferred overwintering sites.

Insect is an important player in the ecosystem as a prey for animals. Moreover, they are a valuable candidate food source for rearing animal. Tenebrio molitor (Coeloptera: Tenebrionidae) larvae are known as a good food source with high protein, unsaturated fatty acid, minerals. Therefore, it has strong potential to substitute the conventional meat consumption. To utilize T. molitor as a feed, the standard mass-rearing protocol is required. To make standard mass-rearing protocol, we tested different temperature(17.5, 20, 22.5, 25, 27.5 and 30°C) conditions for egg, larvae, pupae and adult T. molitor to identify the optimal rearing condition. Hatching was occurred within 15~32.5°C range. However, 17.5~27.5°C was required to get more than 70 % hatching rete. When the eggs were treated in 22.5~27.5°C, all eggs were hatched within 10 days. As larval development, shorter developmental period, higher pupation and eclosion rates were observed within 25~27.5°C temperature range. In addition, we compared the number of egg, oviposition duration and time required to start egg-laying. The minimum egg-laying(258.40±10.86) was observed at 17.5°C, but the maximum(749.10±7.45) was at 27.5°C. The maximum oviposition duration (137.00±12.73 day (mean±S.D.)) was achieved at 27.5°C, but the minimum (87.50±3.54 day (mean±S.D.)) was at 30°C. The time required to start egg-laying was less than 10 days at 17.5, 27.5, and 30°C. To consider all the factors, we concluded that the optimal temperature is 27.5 °C.

The white-spotted chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae) was recently listed as a temporal food ingredient by the Korean Ministry of Food and Drug Safety. Traditionally, this beetle has been regarded as a medicine for suppressing live cancer and preventing liver-related disease. Based on these facts, this beetle has been focused as a economically important insects in Korea. Therefore, this beetle is commercially reared and distributed in Korea. As the economic importance is growing, we have investigated to enhance insect rearing conditions for better commercial value. In this study, we compared two food supplements, clay and charcoal, on the larval weight gain for second instar larvae of P. brevitarsis. Clay and charcoal are generally known as a good adsorbent for heavy metals and bio-waste. However, clay and charcoal is not a conventional feed supplements, so its effects were not investigated for insect rearing. The second instar P. brevitarsis larvae were fed fermented sawdust with seven different combinations of cla and/or charcoal, and measured body weight for 17 weeks until pupated. Addition of clay at 2.5 % w/w of the fermented sawdust diet had no negative effect on larval weight gain, and thus may improve the quality of P. brevitarsis as a commercial food.