Abstract
To study the ecological characteristics of the mulberry longicorn beetle, Apriona germari Hope, Mulberry branches with egg-laid scar were regionally collected from ten mulberry fields during the hibernation. It showed that its distribution was highest in Kyunggi province with 3.05% and lowest in Kyungnam province with 0.28%. The number of the egg-laid scar per branch was single with 87.7% of high frequency and its average size was 2.38 L$\times$1.45 W$\times$0.34D cm. The average diameter of scarred branch was 1.7 cm, ranging from 1.3 to 1.9 cm. the shape of egg was long elliptical with width of $2.32\pm$0.33 mm and with length of $6.606.60\pm$0.55 mm. the weight of egg was $16.6\pm$2.94 mg and the color of the just-oviposited egg was milky white, changing into thick brown with time. The weight and length of the just-hatched larva was $16.6\pm$2.4 mg and $6.36\pm$0.66 mm. respectively. Most of the larvae moved downward inside the branch, showing that 94.2% of larvae for outdoor rearing and 87.9% of larvae for indoor rearing moved downward in the branch. As a result, it was found that it hibernated at egg stage with a higher rate than at larval stage by two or three folds in Kyunggi and Kyungbuk province and contrarily at larval stage with higher rate than at egg stage in Chunbuk, Chunnam and Kyungnam provinces. The survival rate for the egg after hibernation was significantly low with 6.6% and contrarily for the larva after hibernation remarkably high with 91.2%. Although the survival rate of the egg in this survey was relatively low, the result indicated that there were two types of hibernation of A. germari in Korea; egg and larval stage.
우리나라에서 뽕나무 및 과수의 주요 천공성해충으로 알려진 뽕나무하늘소의 지역별 분포, 알 과 부화유충의 크기 및 월동중 생존률, 그리고 월동태 등 생태적인 특성을 조사하였다. 7개도의 뽕밭에서 뽕나무하늘소의 분포를 조사한 결과 경기지역이 3.05%로 가장 높았고 경남지역은 0.28%로 가장 낮았다. 가지당 산란흔 수는 1가지에 1개가 87.7%로 가장 많았고, 산란흔의 크기는 평균 $2.38\times1.45\times0.34$ cm 였으며, 산란흔을 가지고 있는 가지의 지경은 평균 1.7cm 였다. 알의 크기는 단경 $2.32\pm0.33$ mm, 장경 $6.60\pm0.55$ mm로 긴 타원형이었으며, 무게는 $16.6\pm2.94$ mg 이었다. 부화유충은 체중이 $16.6\pm2.4$ mg, 체장은 $6.36\pm0.66$ mm로 유백색이었다. 유충의 가지내 이동방향은 아래쪽으로 이동하는 것이 야외사육의 경우 94.2%, 실내가지육에서는 87.9%로 대부분 아래쪽으로 이동하였다. 수집한 가지의 산란흔을 가지고 월동태를 조사한 결과 경기.경북지역에서 알의 비율이 유충비율보다 2~3배 많았으며 전북, 전남, 경남지역에서는 유충비율이 높았다. 월동후 유충의 생존율은 91.2%로 매우 높은 반면 알의 생존율은 6.6%로 상당히 낮게 나타났다. 이상의 결과로 볼 때, 비록 낮은 비율이지만 뽕나무하늘소의 경우 알로도 월동함을 알 수 있었다.
