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- Feeding preference and intraguild interactions between the parasitoid Trichogramma achaeae and the predator Macrolophus pygmaeus, two biological agents of Tuta absolutaPublication . Borges, Isabel; Oliveira, Luisa; Durão, Ana; Arruda, Patricia; Soares, António O.ABSTARCT: Tuta absoluta is an exotic species and a major pest of tomato crops in Europe. Macrolophus pygmaeus and Trichogramma achaeae are two biocontrol agents widely used in integrated pest management programs of the South American tomato pinworm Tuta absoluta. In this study, we evaluated under laboratory conditions the (i) voracity of M. pygmaeus females fed on single diets of Tuta absoluta eggs parasitized or unparasitized by Trichogramma achaeae, (ii) voracity and feeding preference of M. pygmaeus females provided with mixed diets of Tuta absoluta eggs unparasitized and parasitized by Trichogramma achaeae and (iii) effect of competitive and intraguild interactions between M. pygmaeus and Trichogramma achaeae on the number of Tuta absoluta eggs consumed and/or parasitized. Lastly, we assessed under field conditions the effect of interspecific and intraspecific interactions between natural enemies on the number of Tuta absoluta eggs consumed and/or parasitized.
- Ephestia kuehniella Zeller eggs as a surrogate host to test feeding preference and intraguild interactions between Macrolophus pygmaeus (Rambur) and Trichogramma achaeae Nagaraja and NagarkattiPublication . Costa Miranda Soares, António Onofre; Durão, Ana; Oliveira, Luisa; Arruda, Patricia; Borges, IsabelABSTRACT: 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) in conspecific experiments with increasing density of M. pygmaeus females, the results show an overall decrease on feeding 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) in heterospecific experiments with increasing density of both natural enemies, when using E. kuehniella eggs we found an overall decrease on feeding consumption of 30% and an increase of parasitism rate of 65%.