The Larval Development of Beet Armyworm,Spodoptera exigua (Hubner),(Lepidoptera:Noctuidae) by the Widths of the Head Capsule

파밤나방 유충의 영기별 생장율 비교

The width of head capsule of the beet armyworm, Spodoptera exigua (Hubner), was measured on the 5th generation larvae reared with artificial diet. The mean widths of head capsule of each instar were: 1st, 0.246 mm; 2nd, 0.35 mm; 3rd, 0.546 mm; 4th, 0.809 mm; 5th, 1.242 mm; and 6th, 2.185 mm. The coefficient of variation (%) of each instar were: 1st, 8.6; 2nd, 9.5; 3rd, 15.1; 4th, 11.2; 5th, 12.0; and 6th, 12.9. The growth ratio of each instar were: 2nd, 1.43; 3rd, 1.55; 4th, 1.48; 5th, 1.54; and 6th, 1.76. The fitness(%) to Dyar's law of the measurement of head capsule width were: 1st, 94.7; 2nd, 98.3; 3rd, 98.7; 4th, 94.8; 5th, 94.6; and 6th, 92.2. When the logarithm of the width is plotted against the number of instars, the calculated regression line is highly significient (Log Y = -0.819 + 0.1872X, $r^2$ = $0.9977*{**}$) and Dyar's constant was 1.54.

파밤나방 유충을 실내에서 5세대 동안 인공사육하여 탈피할 때마다 두폭의 최대치를 측정하여 영기별 생장율을 구한 결과 2령 유충의 생장율은 1.43 이었고, 3령은 1.55, 4령은 1.48, 5령은 1.54, 6령은 1.76이었다. 한편 두폭 평？치의 대수를 Ycnr, 령의 수를 X축으로 하여 회귀직선식을 구한 결과 LogY=-0.819+0.1872X($r^{2}$=)었고 Dyar의 법칙과 동일한 기하급수적 생장을 하였다. 각영기별 두폭의 평균치와 Dyar의 법칙과 적합도는 1령 유충이 94.7%, 2령은 98.3, 3령은 98.7, 5령은 94.6 6령은 92.2%었다. Dyar의 항수 (K)는 1.54였다.