Development and reproductive performance of Chrysoperla externa (Neuroptera: Chrysopidae) using preys from wheat crop

Abstract

Biological parameters of Chrysoperla externa were assessed in laboratory. The effect of the preys on biological parameters and reproductive performance were assessed when the following food treatments were provided: Sitobion avenae in all larval instars; Rhopasosiphum padi in all larval instars; Anagasta kuehniella eggs in the first and second instars and Dichelops melacanthus eggs in the third; R. padi in the first and second instars and D. melacanthus in the third instar. All foods provided satisfactory development and reproductive performance. Changing larvae food from A. kuehniella to D. melacanthus did not affect its survival. However, changing larvae food from R. padi to D. melacanthus reduced survival. When larvae were fed with R. padi (1st and 2nd instars) and D. melacanthus (3rd instar), C. externa laid more eggs than when larvae were fed only with aphids. Other parameters either were not affected, or were little affected by the diet change. Results showed that aphis are important food sources for C. externa, and this predator may also predate and develop on D. melacanthus eggs.