Surviving winter: diapause syndrome in the southern green stink bug Nezara viridula in the laboratory, in the field, and under climate change conditions

Abstract

The southern green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) has long attracted attention not only as a serious pest of numerous agricultural crops, but also as a species expanding its range in many parts of the world. Nezara viridula has also been widely used as a model in different experimental studies. The present review focuses on reproductive (i.e. adult) winter diapause, which is the pivotal element of the species' seasonal cycle. Results from numerous field experiments and observations, as well as laboratory ecophysiological investigations conducted during the few last decades, are analyzed and interpreted. Experimental findings are used to describe in detail the dynamics of physiological changes during overwintering. Reproductive diapause in N. viridula is controlled in both sexes by photoperiodic conditions. The induction of diapause is associated with a reversible change of body colour from green or yellow to russet (or brown). The proper timing of adult emergence and the induction of diapause, as well as the size of adults, is vitally important for successful overwintering. Nezara viridula has been shown to respond strongly to the current trend in climate change by shifting the limit of its northern range, particularly in central Japan. Analysis of historic climate data suggests that the environmental conditions during the last few decades have become more favourable for the overwintering survival of N. viridula in many locations in central Japan. This has likely promoted the northward spread of the species. The relationships between reproductive diapause, reversible body colour change, overwintering success and the recent range expansion are analyzed. Perspectives of the range dynamics of the species are discussed in light of further predicted climate change.