An Evaluation of Spodoptera littoralis and Spodoptera exigua as Natural Prey for the Generalist Predator Chrysoperla carnea.

Abstract

Chrysoperla carnea (Stephens) is a common generalist predator in agroecosystems, frequently used for the control of soft-bodied pests in augmentative releases. Better knowledge of its interactions with secondary natural prey is necessary to optimize field biocontrol performance. This work evaluates the eggs and early larvae of Spodoptera exigua (Hübner) and Spodoptera littoralis (Boisduval) as natural prey for the third larval instar of C. carnea, and the predator preferences for different prey stages under varying conditions, assessing the impact on its life cycle and reproduction, in comparison with commercial diets based on Ephestia kuehniella Zeller eggs. Prey choice results were uniform for each dual prey combination irrespective of previous predator conditions (larvae number or fasting). Chrysoperla carnea did not show preference for Ephestia or Spodoptera eggs, but preferred eggs prior to larvae of the natural prey. Diets based on the frozen eggs of natural and factitious prey species showed similar effects on the development and reproduction of predator, but when C. carnea fed on S. exigua larvae, several negative effects were assessed, such as longer preimaginal development, lower adult emergence, and a reduced fecundity. These results are helpful for improving the use of lacewings as biocontrol agents in pest control programs.