실내사육을 통하여 본 땅강아지(Gryllotalpa orientalis Burmeister) 발생에 미치는 인공사료의 효율 비교

Abstract

본 연구는 땅강아지를 사육하기 위한 인공사료를 개발하고자 수행하였다. 이를 위해 사료 A는 밀배아와 어분으로, 사료 B는 쌀겨와 카제인, 사료 C는 감자와 카제인을 주요 영양원으로 조성하였으며 땅강아지의 생존과 발달에 미치는 효율을 비교하였다. 그리고 채집한 암컷이 산란한 산실의 크기, 평균 산란 수, 발육단계별 특징을 조사하였다. 암컷이 실험실에서 산란한 산실의 크기는 외부의 장폭과 단폭이 각각 39.75±1.58, 29.01±1.05 ㎜였으며, 내부 공간은 각 23.8±0.54, 13.62±0.21 ㎜였다. 야외에서 채집한 산실 당 평균 산란수는 55.22±2.38개였으며 실내에서 산란한 산실은 평균 55.44±2.54개로 차이가 거의 없었다. 알의 크기는 산란 직후 2.54×1.44 ㎜로 타원형이었고 시간이 지나면서 크기가 커져 부화 직전에는 3.21×1.98 ㎜였다. 땅강아지의 종령은 8령, 9령, 10령을 관찰하였다. 사료 A에서 각 령의 비율은 22.2, 73.0, 4.8%였으며 사료 B에서는 38.0, 54.0, 8.0%로 두 사료 모두 9령까지 발육하는 개체의 비율이 훨씬 높았다. 우화한 성충의 암수 비율은 사료 A에서 수컷이 53.1%, 암컷 46.9%였고, 사료 B에서는 수컷 53.3%, 암컷 46.7%로 수컷의 비율이 더 높았으며 우화한 모든 성충은 뒷날개가 배 끝을 넘어서지 않는 단시형이었다. 연구기간 중 총 생존 개체 수는 A사료가 39마리, B사료 35마리, C사료 0마리로 A와 B사료에 대한 t-test 결과 유의한 차이를 보이지 않았다(P=0.668>0.05). 그러나 성충으로 생존한 개체는 A와 B사료 간에 유의한 차이를 보였다(P=0.03<0.05). 약충 기간은 사료 A가 평균 206.95±12.12일, 사료 B는 265.14±14.78일이었으며 Mann-Whitney U test 결과 유의한 차이를 보였다(P=0.018<0.05). 본 연구에서는 사료 A로 사육한 개체들이 다른 사료에 비해 성충으로 우화한 개체가 가장 많고 약충 기간 또한 단축되었다. 따라서 사료 A가 땅강아지의 인공사육을 위해 가장 효율적이었다.

This study was conducted to develop an efficient artificial diet for rearing Gryllotalpa orientalis, commonly known as the mole cricket. To accomplish this, the effects of diets composed of wheat germ and fish meal (diet A), rice brain and casein (diet B) and potatoes and casein (diet C) on the survival and development of G. orintalis were evaluated. In addition, the size of the egg cells, numbers of eggs, growth characteristics were investigated. The length of egg cells oviposited in the laboratory was 39.75±1.58㎜. The width of the egg cells was 29.01±1.05㎜ from the outside, and 23.8±0.54, 13.62±0.21㎜ from the inside. The average number of eggs produced by G. orientalis collected in the field was 55.22±2.38, whereas the average number of eggs produced by G. orientalis reared in the laboratory was 55.44±2.54. The average size of the eggs immediately after oviposition was 2.54㎜×1.44㎜, and the shape of the eggs at this time was oval. The average size of the eggs immediately prior to hatching was 3.21㎜×1.98㎜. The final G. orientalis nymphs observed were the 8th, 9th and 10th instar. In addition, the percentage of each instar was 22.2%, 73.0% and 4.8% in G. orientalis provided with diet A. For G. orientalis reared on diet B, the percentage of each instar was 38.0%, 54.0% and 8.0%. The percentage of the 9th instar was the highest in G. orientalis reared on diet A and diet B. There were more males than females when G. orientalis were reared on diets A and B. Specifically, the sex percentage was 53.1% (male) to 46.9% (female) for G. orientalis reared on diet A and 53.3% (male) to 46.7% (female) for those reared on diet B. In addition, all adults observed in this study were short winged with hindwings that did not cover the abdomen. The number of G. orientalis that survived on diets A, B and C was 39, 35 and 0 respectively. The results of a t-test revealed that the survival of G. orientalis fed diet A and B did not differ significantly (P=0.668>0.05). However, the survival of adults reared on diets A and B was significantly different from that of adults reared on diet C(P=0.03<0.05). The length of time that G. orientalis reared on diet A remained in the nymph stage was 206.95±12.12, which was significantly lower than that of G. orientalis reared on diet B (265.14±14.78 days; Mann-Whitney U test, P=0.018<0.05). The numbers of adults was highest and the period of instar was shorter for G. orientalis reared on diet A than for those reared on the other diets evaluated in this study. Therefore, diet A was more efficient for artificial rearing of G. orientalis.