Overview of the Superfamily Pentatomoidea 9
need to include harm in our definition of invasive species, which, as Davis (2009) pointed out, is consis-
tent with usage adopted by the Global Invasive Species Program, International Convention on Biological
Diversity, and the United States National Invasive Species Council. Thus, contributors throughout this
book will use the following definition for their chapters: invasive pentatomoids are nonnative spe-
cies whose populations become established and spread, sometimes exhibiting uncontrolled popula-
tion growth and displacing native populations, and cause adverse socioeconomic, environmental, or
human-health effects.
Species not considered invasive can be termed adventive, immigrant, introduced, and native (Wheeler
and Hoebeke 2009). Adventive is an inclusive term that refers to any species that is not native. Adventives
can be immigrants, that is, species not deliberately or intentionally introduced; or they can be purposeful
introductions, such as natural enemies used in biological control. All remaining species, then, represent
the native fauna. Native species also can become invasive (Buczkowski 2010, Davis et al. 2011), but for
the purposes of this book, all invasive species are adventive, but not all adventive species are invasive.
1.8.2 What Factors Allow Species to Become Invasive?
Researchers long have attempted to identify attributes that enable plants and animals to be successful
invaders and, independently, to determine environmental conditions that favor invasion. The invasion
process, however, is best understood by appreciating the interconnectedness of environmental conditions
and organisms’ traits as well as the significance of propagule pressure (Lockwood et al. 2005, Pyšek and
Richardson 2006, Davis 2009, Su 2013, Jeschke 2014). Several characteristics, however, tend to facilitate
invasiveness, although not all insect species possessing these traits become invasive (Su 2013). Traits
that can favor invasiveness include: (1) ability to move readily in commerce; (2) tolerance of multiple
habitat conditions, such as tolerance of temperature and humidity; (3) ability to reproduce rapidly with
a concomitant increase in population size; (4) ability to compete successfully for resources; (5) lack of
natural enemies; and (6) ability to fly.
1.8.3 Harmful Effects of a Successful Invasion by Insects
Wheeler and Hoebeke (2009) listed several harmful effects including (1) transmission of animal (and
plant) diseases, (2) extreme crop damage, (3), severe damage to forests, homes, and gardens, (4) elimina-
tion of competing native species, and (5) effects on evolution. To these can be added effects on recre-
ational areas and ecosystem processes and the insects becoming nuisance urban pests.
1.9 Invasive Pentatomoids
Invasive insect species worldwide consist primarily of Hymenoptera (Formicidae, Vespidae) but also
many include other groups such as Coleoptera, Isoptera, Lepidoptera, and Hemiptera (e.g., Anonymous
2014). Within the Hemiptera, one such group is the Pentatomoidea. In Europe and Asia, only two
pentatomoid species are listed as invasive, Halyomorpha halys and Nezara viridula (Rabitsch 2008).
However, six invasive species are found in North America, including H. halys and N. viridula. The addi-
tional four species include Bagrada hilaris, Murgantia histrionica, Piezodorus guildinii ( Westwood),
and Megacopta cribraria.
Certain biological characteristics and environmental factors enhance the ability of pentatomoids to
become invasive species, Panizzi (2015) discusses both topics under the following categories: (1) polyph-
agy (feeding on a wide range of host plants), (2) ability to survive unfavorable conditions, and (3) climate
change. In addition, specifically concerning the Neotropics (but also the impact of pentatomoids on a
worldwide basis), other factors include changes in cultivation practices, growth of agribusiness, and
increased trade.
In the United States, injury caused by stink bugs in the native fauna has increased for one major rea-
son, at least for cotton – “a reduction in the frequency of foliar, broad-spectrum insecticide applications”
(Greene et al. 2006). This reduction in pesticide use may have played a role in the dramatic increase in