Functional response of <i>Chrysoperla externa</i> (Neuroptera: Chrysopidae) to two-spotted spider mite, <i>Tetranychus urticae</i> (Acari: Tetranychidae): Implications for biological control

The predator <i>Chrysoperla externa</i> (Neuroptera: Chrysopidae) has great potential for its use in biological pest control programs. In order to assist future biological control programs that use Chrysopidae as a control agent, this research aims to study the behaviour of the green lacewing, <i>C. externa</i>, consuming two-spotted spider mites, <i>Tetranychus urticae</i> (Acari: Tetranychidae). In the laboratory, experiments were carried out to determine the predation behaviour of <i>C. externa</i> on different densities of adults of the two-spotted spider mite, <i>T. urticae</i> (1, 2, 4, 8, 16, 32, and 64 prey). For comparison purposes, the behaviour of <i>C. externa</i> was also studied using eggs from the alternative prey <i>Ephestia kuehniella</i> (Lepidoptera: Pyralidae). The functional response was determined by logistic regression of the number of mites consumed as a function of the initial number of prey using polynomial logistic regression. The random equation was used to describe the parameters of the functional response. The predator <i>C. externa</i> showed a type II functional response consuming both <i>E. kuehniella</i> eggs and <i>T. urticae</i> adults. The results obtained will allow to define the best strategy for the use of green lacewings in the biological control of the two-spotted spider mite, <i>T. urticae</i>.