404 Invasive Stink Bugs and Related Species (Pentatomoidea)
Elevated temperatures, in combination with short-day autumnal conditions, might be beneficial for
diapause induction. The milder winters will increase the likelihood of adult survival until spring.
Consequently, these adults will have a greater chance to pass their genes to the next generation. In a
cumulatively and complex way, these factors will affect the population dynamics of N. viridula, its rela-
tionship with other members of the biotic community and, likely, its pest status. In general, it is known
that insect species have the potential to respond to climate change through phenotypic flexibility or rapid
evolutionary (genetic) responses to strong selection (Bale et al. 2002). As noted by Thomas et al. (2001),
“Improving environmental conditions at existing margins ... are likely to initiate range extensions
purely on the basis of ecological, physiological and population-dynamic processes–requiring no evolu-
tionary change” (p. 579). This is likely what is being observed in the case of N. viridula – the improved
overwintering conditions in central Japan have stimulated northward range expansion of the species
(Musolin 2007; Yukawa et al. 2007, 2009; Tougou et al. 2009). However, Bradshaw and Holzapfel (2008)
contend that all known responses to climate warming involve genetic changes related to seasonality and
diapause syndrome and none of the responses involves an increase in thermal optimum or in heat toler-
ance. Careful monitoring of the performance of N. viridula in its recently colonized areas, as well as a
detailed examination of the species’ plant-insect-symbionts-competitors-natural enemies complex dur-
ing all seasons will be essential for understanding its adaptation to continued climate change.
Nezara viridula will further spread within Europe. As a stowaway and contaminant, it will make use
of the increasing movements of vegetables, crops, and goods with any vehicle. It also will profit from
climate change, responding with increasing population growth that may lead to subsequent spread from
points-of-entry to natural habitats. It is to be expected, although with considerable uncertainty, that
economic damage will increase in Europe in the future. Negative impacts on native biodiversity are less
likely but might be worth investigating in situations of mass occurrences of these bugs.
7.9 Acknowledgments
We thank the following individuals for their assistance and support during this endeavor: Tana B. Luna,
Christopher T. Parker, Lauren A. Ward, and Kendall Wolff. We also thank Norman F. Johnson (Department
of Entomology, Ohio State University, Columbus) for his help with the synonymy of the Telenomus para-
sitoids. Research of Dmitry L. Musolin on diapause in Nezara viridula in Japan was aided by the fruitful
collaboration with Professor Hideharu Numata (Graduate School of Science, Kyoto University, Japan) and
Professor Keiji Fujisaki (Kyoto University, Japan), and supported by the Ministry of Education, Culture,
Science, Sports and Technology of Japan (Grants-in-Aid for JSPS Fellows No. 98116 and L-4562 and STA
Fellow No. 200141 and via The 21st Century COE Program at Kyoto University). The following indi-
viduals contributed via personal communications: Berend Aukema, Naturalis Biodiversity Center, Leiden,
Netherlands; Richard Grantham, Oklahoma State University, Stillwater; Keizi Kiritani, Shizuoka, Japan;
Chris Looney, Washington State Department of Agriculture, Olympia; Abdul Aziz Mohamed, Arabian
Gulf University, Manama, Kingdom of Bahrain; Antônio R. Panizzi, EMBRAPA Trigo, Passo Fundo,
Brasil; Scott Stewart, University of Tennessee, Jackson; Donald B. Thomas, U. S. Dept. Agriculture,
Agricultural Research Service, Edinburg, TX; and Daisuke Tougou, Kyoto University, Japan.
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