Functional Response of Chrysoperla carnea on Early-stage Nymphs of Bactericera cockerelli

The type of functional response that biological control agents present on their prey under laboratory conditions can be used to infer the basic mechanisms of predator-prey interactions in the field. This study compared the type and parameters of the functional response of the three larval instars of the predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) on N1-N2 nymphs of the pest Bactericera cockerelli (Sulc) (Hemiptera: Triozidae). The third larval instar of C. carnea consumed more nymphs compared to the first and second instar. The logistic regression analysis revealed a type-II functional response for the first and second larval instar of the predator, but the third larval instar presented a type-III response. The values of the attack coefficient (a) for the first and second instar were not different, however the values of the handling time (Th) were significantly different, suggesting that both instars have an equal capacity of discovery of the prey, but the second larval instar takes less time to manipulate it. The results of this investigation suggested the use of L1 of C. carnea larvae when a greater quantity of N1-N2 nymphs are present in the field, which could produce greater reduction of the pest populations.