Comportamento, resposta funcional e exposição de crisopídeos ao frio visando ao controle biológico do bicho-mineiro do cafeeiro

Abstract

The present work aimed to study the behavior, functional response and exposure of green lacewings to cold aiming at the biological control of the coffee leaf miner, Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae), one of the main challenges for the Brazilian coffee growing. There are already records about the ability of Chrysoperla externa (Hagen, 1861) and Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae) to prey on the immature stage of L. coffeella, and this fact implies the need for further treatment regarding its biology, interaction with the insect pest, behavior and dispersion in the field. Having in mind that the behavior of a natural enemy can limit its selection as a biological control agent, the first line of research investigates the behavior of C. externa and C. cubana against the coffee leaf miner pupae. A pupae of L. coffeella was available to the first, second and third instar larvae of both predators and the behavior of the larvae was monitored for 25 minutes. It was evaluated the predation rate and the times of foraging, pause and prey manipulation. In addition, the functional response of the second instar larvae of C. cubana to the densities of 1, 2, 4, 8, 16 and 32 leaf miner pupae was evaluated. It was concluded that both green lacewings species have different behavioral characteristics, and both are capable of feeding on L. coffeella pupae. Furthermore, the second-instar larvae of C. cubana present a Type II functional response. The second line addressed is related to anesthesia of adults of C. externa for marking and application of the release-recapture technique, for studies about distribution. Marking a small-sized insect such as green lacewings can be challenging. For this, anesthesia is an alternative to proceed with the marking in order to guarantee the quality of the mark, as well as the morphophysiological integrity and the sensitivity of the specimens treated in the process. Thus, anesthesia through exposure to cold is a viable means of paralyzing specimens for manipulation. Therefore, a methodology was developed that can be easily replicated. Our results indicated the viability of exposure for four minutes at -19ºC, a condition that provides 103 to 208 seconds for manipulation and marking, without the loss of insects.