Exposure of Eocanthecona furcellata (Hemiptera: Pentatomidae) nymphs and adults to high temperatures induces an aestivo-hibernal egg diapause: a strategy for surviving hot summers

The predatory stink bug Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae), which is widely distributed in the subtropics and tropics, is a potential biological control agent for lepidopteran, coleopteran, and hemipteran pests. We investigated development of eggs oviposited by E. furcellata females subjected to various photoperiods (i.e., 8L:16D, 12L:12D, and 16L:8D) and temperature regimes (i.e., 26:26, 30:28, 32:30, 34:32, 35:33, and 36:34 °C; temperatures at light and dark phases, respectively) at different developmental stages. Exposure of E. furcellata nymphs and adults to different photoperiods and temperature regimes affected the development of eggs they subsequently oviposited. Temperatures greater than 30 °C induced diapause in a portion of the eggs, as evidenced by the delayed appearance of the black circle and the red spot, characteristics of early and late stage of embryonic development, respectively. The proportion of diapausing eggs generally increased with increasing temperature exposure, whereas it decreased with advancing developmental stage/age at which E. furcellata was subjected to the temperature regime. Although viability of diapausing eggs was lower than that of non-diapausing eggs, diapausing eggs survived longer under high temperatures. The trade-off between survivability and viability may be a strategy to survive unpredictability of summer temperatures.