Feeding potential and foraging behaviour of Cheilomenes sexmaculata (F.) against cotton whitefly, Bemisia tabaci (Gennadius)

Abstract Feeding potential and foraging behavior are complimentary with each other to determine the efficiency of predator in managing prey host. Predatory potential of grub and adult stages of Cheilomenes sexmaculata (F.) was investigated against the different developmental stages (nymph, pupae and adult) of cotton whitefly, Bemisia tabaci Gennadius, under laboratory conditions. Whereas, foraging behavior was performed as a function of prey/host density. The fourth instar grub of C. sexmaculata exhibited the highest feeding potential (41.74±8.13 adults, 33.41±3.95 pupae and 31.33±3.95 whitefly nymphs) followed by third instar grub (23.85±5.40 adults, 21.44±3.36 pupae and 19.37±2.53 whitefly nymphs), second instar grub (13.19±3.18 adults, 11.89±1.84 pupae and 9.48±1.99 whitefly nymphs) and first instar grub (10.15±1.70 adults, 9.15±1.35 pupae and 7±1.45 whitefly nymphs). The female beetle consumed the highest prey’s (1445.29±312.77 adults, 1364.88±294.38 pupae and 1374.35±296.20 whitefly nymphs) followed by male beetle (1390.12±229.35 adults, 1308.18±270.51 pupae and 1325.35±275.81 whitefly nymphs) throughout their life span. Both the Roger’s and Holling’s model indicated type II functional response curve for all the grub and adult stages of C. sexmaculata . Adult female showed the highest coefficient of attack (4.65) and the maximum rate of predation (37.5), whereas the lowest handling time (0.02) was recorded for the male against B. tabaci nymphs. Against the B. tabaci pupae, fourth instar grub showed the highest coefficient of attack (1.30), whereas female beetle showed the maximum rate of predation (38.18) with the lowest handling time (0.04). However, against the B. tabaci adults, female beetle showed the highest coefficient of attack (6.87), whereas the fourth instar grub showed the maximum rate of predation (41.7) with the lowest handling time (0.01). Hence, it is advocated to release the fourth instar grubs and females of C. sexmaculata collectively for the augmentative biological control of B. tabaci in the IPM programme .