Overview of the Superfamily Pentatomoidea 7
[e.g., Halyomorpha halys (Stål)], the female defecates on the egg, and the first instars acquire symbionts
by feeding on her feces (Taylor et al. 2014a). Also, the first instars of Nezara viridula apparently do
feed (Esquivel and Medrano 2014), although the probing may be for water rather than nutrient uptake.
Among the other families of pentatomoids, the first instars of at least some species of Thyreocoridae and
Cydnidae are active and feed on the host plants (McPherson 1982, Sites and McPherson 1982, Bundy and
McPherson 2009, Cervantes et al. 2013).
For those species that aggregate during the first stadium, the later instars begin to gradually and pro-
gressively disperse. This tendency to remain clustered in earlier instars may provide some protection
from predation (Lockwood and Story 1986).
As the nymphs pass through the various stadia, subtle morphological changes are evident, particularly
in the fourth and fifth instars. These two older instars can be distinguished from younger instars by the
lengths of the wing pads, which are longest in the fifth instars. The eggs and nymphal instars have been
described for many pentatomoid species, including the six invasive species discussed in this book (e.g.,
Moizuddin and Ahmad 1975, McPherson 1982, McPherson and McPherson 2000, Hoebeke and Carter
2003, Zhang et al. 2012, Leslie et al. 2014, Taylor et al. 2015).
Species of pentatomoids in northern and central North America generally are uni- or bivoltine with the
number increasing to five in the extreme south (McPherson 1982, McPherson and McPherson 2000). The
diversity of seasonal cycles known in the Pentatomoidea, mostly from the Temperate Zone, including
those that are uni-, bi-, multi-, and semivoltine, is reviewed in Chapter 12. Further discussion focuses on
the ecological importance of photoperiodic and thermal responses in natural or artificial expansions of
pentatomids outside their original ranges.
1.5 Predators and Parasitoids
Pentatomoids are attacked by numerous invertebrate and vertebrate species, both parasitoids and preda-
tors. The parasitoids consist primarily of hymenopteran egg parasitoids (e.g., Scelionidae) and tachi-
nid flies (Tachinidae). Numerous predators have been recorded, including predaceous stink bugs (e.g.,
Podisus). Among vertebrates, birds often have been reported as predators of pentatomoids (McPherson
1982). Native fungal pathogens, nematodes, and other parasitic organisms also have been recorded from
invasive stink bugs (e.g., Sosa-Gómez and Moscardi 1998).
As with most other invasive insect pests, alien pentatomoids have arrived in new geographic areas
without their most important coevolved natural enemies, and, thus, some have been targets for classical
biological control. One of the best-known projects against an invasive pest insect was the introduction of
the egg parasitoid Trissolcus basalis (Wollaston) (Platygastridae) for management of the southern green
stink bug, Nezara viridula, across five continents (Walker A. Jones, personal communication).
Tachinid flies attacking pentatomids include certain parasitic species that have been subjects of classi-
cal projects. The recent invasions of the brown marmorated stink bug, Halyomorpha halys; the painted
bug, Bagrada hilaris (Pentatomidae); and the bean plataspid or kudzu bug, Megacopta cribraria ( F.)
(Plataspidae) into North America have triggered projects that are in various stages of progress (Walker
A. Jones, personal communication).
1.6 Chemical Defenses of Pentatomoids
Pentatomoids, like many other heteropterans, have a rich array of semiochemical compounds that
function as pheromones, allomones, synomones, and kairomones. Although probably best known for
their allomonal scent-gland secretions, pentatomoids have many semiochemical intra- and interspe-
cific interactions that are just being uncovered. Among the increasingly evident complex chemistry and
relationships are defenses against parasitoids and predators, eavesdropping by these natural enemies,
cross-species attraction, and intraspecific variation in production of and response to semiochemicals
based on life stage and physiology. The exciting discoveries in this area and the potential and actual uses
of these chemicals in pest detection, monitoring, and management are addressed in Chapter 15.