Effect of Coleus size and variegation on attack rates, searching strategy,and selected life history characteristics of Cryptolaemus montrouzieri (Coleoptera : Coccinellidae)

Twenty-four-hour attack rates and the search strategy of third instar Crypt olaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) attacking 1 to 16 third instar Planococcus citri Risso (Homoptera: Pseudococcidae) were measu red on green and yellow-variegated Solenostemon scutellarioides (L.) Codd ( = Coleus blumei (Bentham)) (Labiatae) plants of different sizes. Selected l ife history characteristics of C. montrouzieri fed different amounts of P. citri as prey from third instar to adults were also examined. On average, p redators attacked 1 to 4 mealybugs, depending on the number of mealybugs an d plant size. There was no effect of plant color on attack rates. Attack ra tes were positively related to prey density, whereas the estimated area sea rched by predators was inversely related to prey density. Analyses suggest that leaf area was the plant characteristic that most affected attack rates . Predators fed few prey had a decrease in body weight and survival. The im plications for the use of C. montrouzieri in biological control are discuss ed. (C) 2000 Academic Press.