Ephestia kuehniella eggs as a surrogate host to test feeding preference and intraguild interactions between and Macrolophus pygmaeus and Trichogramma achaeae

Abstract

Mass rearing of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) eggs is a laborious task requiring investment of time, equipment and man hour work. The use of a surrogate prey/host, as Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), easily obtained and maintain, could be an option to undertake experiments. The aim of this study was to test to what extent the eggs of E. kuehniella is a suitable surrogate host of T. absoluta eggs to test for feeding preference and intraguild interactions between Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) and Trichogramma achaeae Nagaraja and Nagarkatti (Hymenoptera: Trichogrammatidae). Our results shows that E. kuehniella eggs is a suitable surrogate host to test for feeding preference and intraguild interactions between natural enemies, taking in consideration that i) under single diet, feeding on T. absoluta eggs is expected to be twice that on E. kuehniella, ii) whether offering T. absoluta or E. kuehniella under different ratios of parasitized vs unparasitized eggs, feeding preference was always toward non-parasitized eggs iii) conspecific experiments with increasing density of M. pygmaeus females, the results revel an overall decrease on feeding consumption of 38,7% of E. kuehniella compared with T. absoluta eggs but experiments with T. achaeae show an overall increase in parasitism rate of 78,2% of eggs toward E. kuehniella eggs iv) Heterospecific experiments with increasing density of both natural enemies, when using E. kuehniellaeggs we found an overall decrease on feeding consumption of 30% and an increase of parasitism rate of 65%.