Benefícios do mel e pólen de forrageiras nos parâmetros biológicos de Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

Abstract

Investigations were carried out of the benefits of honey and pollen of two forage species on biological aspects of the adult phase of Chrysoperla externa (Hagen, 1861). Mating pairs of the predator were placed in cylindrical PVC cages (10 cm x 10 cm) and maintained in climate-controlled chambers at 25 ± 1º C, 70% RH and 12-hour photophase. They were fed diets of yeast + honey (1:1) and castor pollen without the addition of honey (controls), and the following treatments: elephant grass pollen; signal grass pollen; elephant grass pollen + honey; signal grass pollen + honey. When they were only given castor pollen, the green lacewings had shorter life spans and did not lay eggs. The prelaying and laying periods were not influenced by the different food sources with the presence of honey, regardless of the protein source. The number of eggs/female was greater for the diet with yeast + honey (1:1), followed by elephant grass pollen + honey, castor pollen + honey, and signal grass + honey. It was found that the pollen of the tested plants had positive effects on the biology of C. externa, when honey was added as a carbohydrate source. Therefore, to aid the performance and permanence of this natural pest predator in these forage crops, it is recommended that the lacewings’ food be supplemented with flowers or other sources of carbohydrates.