BIOLOGY, PREDATORY POTENTIAL AND FUNCTIONAL RESPONSE OF RHYNOCORIS FUSCIPES (FABRICIUS) (HEMIPTERA: REDUVHDAE) ON RICE BROWN PLANTHOPPER, NILAPARVATA LUGENS (STAL) (HOMOPTERA : DELPHACIDAE)

摘要

The biology of Rhynocorisfuscipes a commonly found assassin bug in rice fields was studied on the rice brown planthopper, Nilaparvata lugens. R. fuscipes laid deep brown coloured eggs in small clusters of 6 to 12 and female laid 46.1±14,9 eggs. The stadial durations of 1,11, HI, IV and V instar nymphs were 12.67±0.23,13.07db0.93,15.23±0.38,27.38 ± 0.55 and 44.88±0.76 days respectively when fed on BPH, The total stadial period of A fuscipes from egg to adult was 113.23±0.57 days. The nymphal mortality was 46.7% from first to fifth instar. The adult male longevity was shorter than females. Adult male lived for 66.00±13.00 and female 75.17±7.6 days and their sex ratio was 1:3 (male to female). The predatory rate of /J. fuscipes was 98.5*13.63.The predation rate of I, II, III, TV and V instar nymphs were 0.84±0.06,1.14±0.09,1 J3±0.07,1.13±0.08, and 1.41±0.06 per day. R. fuscipes exhibited Holling's type II functional response as indicated by the positive correlation obtained between the prey density and the number of prey killed by the predator. The attack ratio decreased as the prey density was increased. A negative correlation was obtained between the searching time and the prey density.