Interactions of six spotted ladybird beetle, Cheilomenes sexmaculata (F.) with its host Phenacoccus solenopsis Tinsley and Intraguild members

Cotton is the preferred host of the mealybug, Phenacoccus solenopsis Tinsley. The foraging behavior and intraguild interaction studies are important for understanding the predator-prey dynamics and for predator’s full utilization in augmentative biological control. Functional response of Cheilomenes sexmaculata (F.) to different densities of P. solenopsis was studied under laboratory conditions. The results indicated that the predator male and female exhibits type-II functional response. The maximum average prey killed by females (30.1) and males (20.5) was achieved at prey density of 80 and 60 per predator, which decreased to 26.8 and 15.6 at prey density of 120 insect per predator. Longest handling time was recorded for males (1.2 hrs) in comparison with females (0.72 hrs) . Maximum theoretical predation rate was 19.8 mealybugs for males and 33 mealybugs for females during 24h exposure time. Possible Intraguild Predation (IGP) between C. sexmaculata and some other coccinellids, Coccinella septempunctata L., Brumoides suturalis Mulsant, Cryptolaemus montrouzieri Mulsant and Scymnus coccivora Ayyar was evaluated in the second step of the study. Among these predators, C. septempunctata was the most competitor as its adult was able to attack even the fourth instar larvae of C. sexmaculata . It has been found that C. montrouzieri underwent lesser predation by other species and showed maximum preference to mealybugs rather than involving in IGP with other species. Females of C. sexmaculata were found to be more efficient than males. Mealybug destroyer, C. montrouzieri underwent lesser predation by other coccinellids in IGP and showed maximum preference to cotton mealybugs. Hence, it could be combined with C. sexmaculata up to some extent for augmentative control of mealybugs.