The tachinid parasitoids of the adult stage of phytophagous stink bugs: a vacant niche in Piezodorus guildinii (Hemiptera: Pentatomidae)?

BARAKAT, MARÍA CANDELA; LILJESTHRÖM, GERARDO GUSTAVO; CINGOLANI, MARÍA FERNANDA

Simposio; 6th INTERNATIONAL SYMPOSIUM ON BIOLOGICAL CONTROL OF ARTHROPODS (ISBCA); 2022

The phytophagous hemiptera of the Pentatomidae family are pests of several crops. Among them, Piezodorus guildinii and Nezara viridula are two of the most harmful stink bugs. Two guilds of natural enemies attack them: the oophagous parasitoids and those of the adult stage. Adults of P. guildinii are not commonly parasitized, unlike N. viridula, which is frequently attacked by Trichopoda giacomellii (Diptera: Tachinidae), suggesting a vacant niche on that pest. Only a few references are known regarding the unusual occurrence of adult parasitism of P. guildinii by tachinid flies. Under particular circumstances a parasitoid may include a non-preferred species among its potential hosts. For example, as the life expectancy of a parasitoid decreases, its selectivity also decreases, lowering the quality threshold below which hosts are rejected. In this work, the potential of P. guildinii as a host for T. giacomellii females of different ages was evaluated: young and old parasitoids (1 and 5 days old, respectively). Parasitism in each treatment didn’t show statistically significant differences, although the proportion of replicates parasitized by old female parasitoids was higher than that obtained from young females. Even though progeny’s emergence rate was low in both cases, we obtained a viable F1 generation. These data, although preliminary, indicate that T. giacomellii attacks P. guildinii and is able to develop on this host, resulting of interest for the design of integrated management strategies for this pest, mainly in a scenario where N. viridula populations are decreasing in density and P. guildinii is becoming more abundant.