침입 외래종 등검은말벌 (Vespa velutina nigrithorax)은 2003년 한국에 침입한 이후 남한 전체로 확산되면서 공중 보건적, 경제적, 생태적 피해를 야기 시키고 있다. 그러나 확산과 분포에 대한 추적 연구를 제외하고 생물학적 기초 연구가 미비하다보니 실제로 현장에서는 비효율적인 방제 및 관리 방법이 많이 시행되고 있다. 따라서 본 연구에서는 각 피해별로 행동학적 특성을 분석하여 등검은말벌의 피해를 저감하기 위한 기초 생태적 자료를 확보하는데 있다. 먼저 등검은말벌의 확산에 단초가 되는 생태적 지위를 파악하기 위해 5종의 토착 말벌들과의 공격행동과 크기 차이를 비교 하였다. 그 결과 등검은말벌은 털보말벌보다는 공격성이 강하지만, 나머지 말벌보다는 약한 것으로 나타났다. 또한 몸 크기에서도 비슷한 결과를 나타내었다. 따라서 등검은말벌의 생태적 지위는 털보말벌보다는 높지만 나머지 종에 비해서는 낮은 것으로 나타났다. 이는 등검은말벌이 확산 하는데 있어 강력한 토종말벌들을 피해 도시 및 산림 가장자리에 서식하고, 도로망이나 해안가를 따라 확산이 이뤄진 이유로 보인다. 두 번째로 양봉장에서 등검은말벌의 사냥 능력을 파악하기 위해 사냥 활동을 분석하였다. 등검은말벌의 사냥시간은 총평균 42.04초로 나타났고 여름 (50초대) 보다는 가을(10초대)에 사냥시간이 훨씬 짧았다. 공격 시도에서도 여름보다는 가을에 훨씬 적은 시도로 사냥을 성공하였고 사냥 성공율은 평균 84.2%이었으며, 9월에는 약 97% 이상의 성공율을 나타내었다. 이는 8월 중-9월에는 경험많은 나이든 일벌들의 수가 풍부하여 사냥 능력이 최고조에 달한 것으로 보인다. 또한 토종인 털보말벌과의 비교에서도 사냥 시간은 3배 정도 빨랐으며 사냥 성공률도 약 35%가 높아 외래종 등검은말벌의 사냥 능력이 월등히 앞선 것으로 나타났다. 세 번째로 최근 외래종 등검은말벌의 침입에 따른 말벌의 쏘임 사고가 증가하는 가운데 말벌 공격에 대한 잘못된 대처방안이 유포되면서 피해를 가중시키고 있다. 따라서 색깔, 털, 소리, 냄새에 대한 등검은말벌의 방어행동 분석을 실시하였다. 총 8개 색(검정, 갈색, 노랑, 녹색, 주황, 회색, 빨강, 흰색)에 대한 방어행동은 대체적으로 검고 짙은색에 높게 나타났고 털이 있을 경우 약 3배 정도 더 높은 방어행동이 나타났다. 그리고 털보다는 검은 색깔에 더 민감하게 반응하였다. 소음에 대한 반응은 전혀 없었으며 냄새에서도 향수, 음식, 음료 등에 대한 반응은 없었으나 사람의 호흡에는 방어행동이 매우 극심히 나타났다. 이는 이산화탄소 농도와 더불어 대기온도보다 높은 호흡 온도에 의해 자극이 된 것으로 보인다. 이러한 자극들은 대부분 새나 대형동물과 같은 잠재적 포식자의 생리적 특징으로 진화적으로 벌들이 이를 인지하는 감각의 발달로 나타난 방어행동으로 보여진다. 마지막으로 등검은말벌의 집단 공격 시 나타날 수 있는 여러 상황에 대해 행동학적으로 피해를 최소화 할 수 있는 대응행동 실험을 실시하였다. 벌집 앞 3m 이내로 접근시 일벌들의 방어 행동이 나타나는데 큰 제스쳐가 있을 경우 공격율이 더 높았다. 벌집을 건드린 후 도망갈 때 천천히 걸으면 20m까지도 집중적 공격을 받으나 뛰어 도망갈 때는 10m 정도 벗어나면 1마리 이하의 공격을 받는다. 비록 1-2마리는 300m까지 추격하여 공격하기도 하였으나 집단 공격의 피해를 줄이기 위해서는 최소 10m 이상 빨리 벗어나는 것이 최선이다. 또한 벌이 집단으로 공격할 때 그 자리에서 엎드려도 말벌의 공격은 거의 줄어들지 않았다. 벌들은 또한 공격할 때 검은 머리털에 민감하게 반응할 뿐만 아니라 가장 근접한 대상을 공격하기 때문에 벌집이 메달려 있을 경우 말벌들은 머리를 가장 집중적으로 공격하였다. 따라서 벌집을 건드려 벌들이 기습적으로 공격 할때는 벌집 또는 벌이 접근해 오는 반대방향으로 급히 얼굴을 돌려 얼굴 부위를 먼저 보호하고 손, 팔로 방어선을 치면서 앞으로 숙여서 전력으로 도망가야 생존 확률이 높아진다. 또한 챙이 넓은 모자를 쓰면 약 82%의 벌을 1차적으로 막아줘 매우 유용하다.
The invasive alien species Vespa velutina nigrithorax was introduced in Korea in 2003 and spread throughout the country, affecting public health, economy, and the environment. The lack of basic biological research on this species?studies were mostly focused on the spread and distribution of this species?resulted in the development of many ineffective control and management methods. Therefore, in this study, I analyzed the behavioral characteristics of V. v. nigrithorax to understand their effect on public health, economy, and ecology and develop appropriate measures for eradication of V. v. nigrithorax. To understand the ecological niche that is the basis for the spread of V. v. nigrithorax, the attack behavior and size difference of this species was compared with those of five native hornets. V. v. nigrithorax was more aggressive and with larger body than Vespa simillima, but weaker and smaller than the other four rest hornet species. Thus, V. v. nigrithorax was superior only to V. simillima. V. v. nigrithorax nests along the forest edge and in urban areas to avoid the stronger native hornets, and spreads along the roads or the coastline. Foraging activity of V. v. nigrithorax was analyzed to understand its foraging ability in the apiary. The average foraging duration of V. v. nigrithorax was 42.04 s; it was much shorter in the fall (10 s) than in the summer (50 s). Foraging was successful with much fewer attack attempts in the fall than in summer; the average foraging success rate was 84.2%. In September, the foraging success rate exceeded 97%, which is attributed to abundant number of experienced old workers in August-September. The foraging duration and foraging success rate of V. v. nigrithorax was three times longer and about 35% greater, respectively, compared with those of the native hornet V. simillima, indicating the superior foraging ability of V. v. nigrithorax. As the incidence of wasp stinging events due to the invasion of V. v. nigrithorax increased in recent years, misinformation about hornet attacks was spreading and the frequency of accidents multiplied. Therefore, V. v. nigrithorax defensive behavior was analyzed in relation to color, hair, sound, and olfactory stimuli. The defensive behavior, which was tested against eight colors (black, brown, yellow, green, orange, gray, red, and white), was generally high for black and brown, and about three times higher when associated with hair. The hornet was more sensitive to black color than to hair. There was no reaction to noise, perfumes, foods, and beverages, but defensive behavior was very intense in response to human breathing, which was contributed to temperature increase and grater CO2 concentration in human breath. Most of these stimuli are characteristics of potential predators, such as birds and large animals, and are seen as defensive behaviors that evolved along with the development of sensory organs. Lastly, I conducted a response action experiment to minimize the behavioral damage in various situations that may occur during a multiple attack by V. v. nigrithorax. When approaching within 3 m of the nest, the workers appear defensive behavior, and any a large gesture will increase the risk for attack. A person that slowly walks away from the nest after disturbing it will be exposed to intense attack by hornets up to 20 m distance, whereas the one who runs 10 m away from the nest will receive less than one attack. Although occasionally one or two hornets will chase and attack the person up to 300 m away from the nest, the best approach to avoid multiple attacks by hornets is to rapidly escape at least 10 m away from the nest. The workers that attacked in a group hardly diminished their attack even when the person crouched. The hornets were excited by dark hair, and because they typically attack targets that are closest to their hanging nests, they attacked the head most intensively. Therefore, to escape an attack by hornets after unexpected contact with the nest, the person should turn rapidly away from the nest, protect the face with hands and arms, lean forward, and run away as fast as possible. In addition, wearing a wide brim hat is very useful as it lowered the incidence of wasp attacks by about 82%.
Introduction 11. Invasion of major alien species in Korea 12. Factors that determine ecological niches and spread according to the prey competition of invasive wasps 23. The economic value and diseases of honeybees and the defensive mechanisms against hornets 34. Wasp threats to people 55. Dissemination of inaccurate information about wasps and lack of scientific research 86. Purpose of this study 9Chapter 1. General characteristics of Vespa velutina nigrithorax 121.1. Taxonomy 141.2. Nest and its population 151.3. Life cycle 171.4. Diet 181.5. Invasion and spread 181.6. Impact 221.6.1. Economic impact 221.6.2. Public health impact 231.6.3. Ecological impact 251.7. Density 251.8. Designation of V. v. nigrithorax as invasive alien species and ecological disturbance organism 261.9. Research trends of V. v. nigrithorax in Korea 26Chapter 2. Interspecific hierarchies of aggressiveness and body size among Vespa velutina nigrithorax and five native hornets in Korea 282.1. Materials and Methods 292.1.1. Study species and experiment sites 292.1.2. Behavioral observation experiment 302.1.3. Behavioral description, intensity scores, winning percentages, and aggressive behavior trends 312.1.4. Morphological measurements 322.1.5. Statistical analysis 322.2 Results 342.2.1. Description of aggressive behavior 342.2.2. Aggressive intensity, winning percentages, and aggressive behavior trends 422.2.3. Body size 472.3. Discussion 492.3.1. Spread effect of V. v. nigrithorax on interspecific competition in Korea 492.3.2. Interspecific hierarchies of Korean Vespa species 53Chapter 3. Foraging behavior of Vespa velutina nigrithorax at Apis mellifera hives in Korea: foraging duration, attack attempts, and success rate 563.1. Materials and Methods 573.1.1. Study area and dates 573.1.2. Measurement of foraging activities 583.1.3. Effect of weather on foraging activities 593.1.4. Comparison of V. v. nigrithorax with native hornet species 593.1.5. Statistical analysis 593.2. Results 613.2.1. Foraging duration, attack attempts, and success rate 613.2.2. Effect of weather on foraging duration and attack attempts 673.2.3. Comparison with native hornet species 693.3. Discussion 71Chapter 4. Defensive behavior of Vespa velutina nigrithorax against potential aggressors 754.1. Materials and Methods 764.1.1. Experimental Species, Date, and Location 764.1.2. Color 794.1.3. Hair 794.1.4. Noise 804.1.5. Olfactory 814.1.6. Statistical analysis 824.2. Results 834.2.1. Color 834.2.2. Hair 854.2.3. Noise 874.2.4. Olfactory 874.3. Discussion 894.3.1. Color 894.3.2. Hair 914.3.3. Noise 924.3.4. Olfactory 924.3.5. Proposed countermeasures against social wasp attacks 94Chapter 5. What should you do when hornets attack 965.1. Materials and Methods 975.1.1. Tested species, date and locations 975.1.2. Defensive behavior following approaching the nest 985.1.3. Avoidance and chase distance 995.1.4. Standing & crouching 995.1.5. Target locations of attack on the dummy 1005.1.6. The effects of wearing hats 1015.1.7. Statistical analysis 1015.2. Results 1035.2.1. Defensive behavior following approaching the nest 1035.2.2. Avoidance and chase distance 1035.2.3. Standing & crouching 1055.2.4. Targeted locations of attack on the dummy 1055.2.5. The effects of wearing a hat 1085.3. Discussion 109Conclusion and further study 114References 118Appendices 139Korean Abstract 169