The eggs and nymphs of predatory stink bugs (Hemiptera: Pentatomidae: Asopinae): what do we know?

Abstract

The Asopinae are known for their predatory behavior, differing from the phytophagous habits of most pentatomoids, feeding mostly on soft body insects such as larvae of Lepidoptera and Coleoptera. For this reason, asopines have been studied as biological controllers in integrated pest management programs. Notwithstanding their clear relevance, the general knowledge about Asopinae has important gaps, especially regarding immature. Thus, the importance of studying eggs and nymphs of true bugs (Heteroptera) is evident, contributing to understand their classification, biology, and evolution. In this perspective, we conducted a research about immature of predatory stink bugs, highlighting critical features for identification. We present: (1) a literature overview about eggs and nymphs of predatory stink bugs guided by selected categories; (2) images of females laying eggs of ten species and nymphs of thirty-four species, obtained on websites with a citizen science approach; (3) a comparative morphology of immature of six species reared under laboratory conditions, which we examined using light and scanning electron microscopy. We found a remarkable morphological diversity of both eggs and nymphs of Asopinae, revealing key features to establish diagnoses for identification and potential characters to phylogenetics, such as the aero-micropylar processes and chorion scultpturing of the eggs; and the coloration, labium and abdominal plates morphology of nymphs. The results show that little is known about Asopinae immature considering the diversity of the group; however, information obtained by citizen science initiatives, for instance, can improve this knowledge.