Dechorionation and Permeabilization of Podisus nigrispinus (Heteroptera: Pentatomidae) Eggs: Limiting Factors for Cryopreservation

Abstract

Cryopreservation protocols have been developed for eggs of Diptera, Lepidoptera, and Hymenoptera; however, for Heteroptera, such as Podisus nigrispinus Dallas, 1851 (Pentatomidae), no procedures have been described yet. The objective of this study was to evaluate the processes of dechorionation and permeabilization on the viability of eggs of P. nigrispinus with different embryonic ages. In the laboratory, embryos of 24, 48, 72, and 96 h of age were submitted to sodium hydroxide, sodium hypochlorite, isopropyl, and hexane solutions for dechorionation and permeabilization. The experiment was carried out in a 4 × 8 factorial scheme. Sodium hydroxide affects embryo viability; however, 96-h-old embryos showed higher viability when compared with 24, 48, and 72-h-old embryos. Microscope observations showed that, after the treatments, the chorion of P. nigrispinus eggs was reduced to 5.11 ± 0.30 µm. These solutions for dechorionation and permeabilization of P. nigrispinus eggs together with embryonic age affect the viability of embryos to be cryopreserved.

Keywords: embryo; stinkbug-predator; vitrification.