Invasive Stink Bugs and Related Species (Pentatomoidea)

6 Invasive Stink Bugs and Related Species (Pentatomoidea)

Eggs of the Pentatomoidea, though superficially similar as a group, are variable in their morphology
depending upon the family, features of which are helpful in their identification (see Southwood 1956,
Hinton 1981, Javahery 1994). A ring of micropylar processes of various shapes and sizes is present
at the cephalic end of the pentatomoid egg. Members of the Pentatomidae, Plataspidae, Scutelleridae,
and Tessaratomidae have a thick chorion (thinner in the Plataspidae) with a pseudoperculum, a caplike
structure through which the hatching nymph emerges (Hinton 1981, McPherson 1982) (Figure 1.1C, D).
However, members of the Acanthosomatidae, Cydnidae, and Thyreocoridae have a thin chorion, which
splits irregularly when the nymph hatches (McPherson 1982). An egg burster, which aids in emergence
from the egg, is present in embryos of at least some species in all these families (Hinton 1981, McPherson
1982).
In most Pentatomoidea, eggs are laid on the host plants in round or subhexagonal clusters on the leaves
or in longitudinal rows generally on the leaves and stems; the eggs adhere to the plant and to each other
by a sticky secretion (Figure 1.1B). Members of the Plataspidae deposit their eggs in two rows along
with fecal pellets containing bacterial symbionts that enhance survival of the nymphs (Hosokawa et al.
2007, Ruberson et al. 2013; see Chapter 5). In rare instances, the eggs are laid singly in the soil although
the sticky secretion is still evident (e.g., Bagrada hilaris, Taylor et al. 2014b; see Chapter 3). In the
Thyreocoridae, eggs are laid singly on the host plant; and in the Cydnidae, eggs are laid in loose clusters
in the soil (McPherson 1982). In the closely-related Parastrachiidae, Parastrachia japonensis Scott lays
its eggs in clusters of up to 100 in shallow nests in the leaf litter (Filippi et al. 2001). Recently, Cervantes
et al. (2013) reported that the cydnid Melanaethus crenatus (Signoret), lays its eggs singly in the soil,
usually close together.
The eggs usually are abandoned immediately after oviposition but members of most pentatomoid
families contain species in which females exhibit parental care (e.g., Acanthosomatidae, Pentatomidae,
Scutelleridae, Cydnidae, and Parastrachiidae), guarding the eggs and young nymphs (e.g., Eberhard 1975,
McPherson 1982, Sites and McPherson 1982, Tallamy and Schaefer 1997, Peredo 2002, Costa 2006).
Pentatomoids have five nymphal instars (Figure 1.2). The first instars generally are gregarious, inac-
tive, and remain atop or near the egg shells during the stadium. If they are disturbed, the cluster begins to
break up and the individuals seem unable to reaggregate. Although first instars of pentatomids generally
are thought not to feed (McPherson 1982), they may acquire symbionts by sucking the secretions covering
the shells of the unhatched eggs (McPherson 1982, McPherson and McPherson 2000). In some species

A B

D E

C

FIGURE 1.2 Nymphal instars of a typical stink bug, Chlorochroa ligata. A-E, First through fifth instars, respectively.
(Modified from Morrill 1910).