708 Invasive Stink Bugs and Related Species (Pentatomoidea)
only in dry weather, and both lures caused localized aggregations of the bugs around the lures, drawing
them away from areas in which larval sphingid prey were concentrated, consistent with Kaplan’s (2012)
suggestion that HIPVs might produce undesirable results under some circumstances of field deploy-
ment. Dickens (1999) showed that P. maculiventris and Perillus bioculatus were not attracted to com-
mon green leaf volatiles such as (Z)-3-hexen-1-ol and (E)-2-hexenal, proposing that unlike several other
HIPVs tested, these are not reliable cues of prey presence for these predators.
In contrast to predatory species, herbivorous pentatomids apparently are not attracted to HIPVs, and
indeed, they may avoid plants damaged by feeding to limit competition with conspecifics or to avoid
attack by natural enemies that may be attracted to HIPVs. For example, in Y-olfactometer bioassays,
Euschistus heros was not attracted to HIPVs emitted from soybean plants damaged by conspecifics but
was attracted to constitutive volatiles from soybean. Similarly, Tibraca limbativentris females (but not
males) preferred volatiles emitted by undamaged rice plants compared to volatiles emitted by rice plants
fed upon by conspecifics (Melo Machado et al. 2014).
Several studies have shown that egg parasitoids exploit HIPVs indirectly to locate eggs of their hosts.
For example, the egg parasitoid Telenomus podisi exploited HIPVs indirectly to locate Euschistus heros
eggs (Moraes et al. 2005b, 2008a; Michereff et al. 2011) or eggs of another host, Tibraca limbativentris
(Melo Machado et al. 2014). In contrast, another egg parasitoid, Trissolcus basalis, showed no prefer-
ence for constitutive versus induced volatiles produced by rice plants fed on by T. limbativentris (Melo
Machado et al. 2014). Recently, Michereff et al. (2014) reported that T. podisi was attracted to a soybean
cultivar that released higher amounts of constitutive and herbivore-induced volatiles compared to other
cultivars, and, in this cultivar, Euschistus heros eggs were more heavily parasitized than in other cul-
tivars. In addition, parasitism occurred during the R5-R7 stage of soybean cultivation when E. heros
populations are high, so the effect of the parasitoids was maximized (Borges et al. 2011, Michereff et al.
2014). Colazza et al. (2004) reported that Nezara viridula feeding on beans also elicited HIPVs that
attracted the egg parasitoid Tr. basalis.
Oviposition by herbivores also may induce production of plant volatiles that attract parasitoids, and/or
nonvolatiles that arrest them. Conti et al. (2010) demonstrated that with Murgantia histrionica hosts, a
complex of host- and plant-produced compounds aided host egg location by the egg parasitoid Trissolcus
brochymenae. Plant volatiles were apparently adsorbed into the plant epicuticular wax layer (Frati et al.
2013). Oviposition-induced plant volatiles now have been demonstrated for multiple herbivore-parasitoid
pairs (Hilker and Fatouros 2015), but, to date, this is the only known system involving Pentatomoidea.
15.5 Overview: Semiochemicals in Life History of Pentatomoids,
and Practical Applications15.5.1 Patterns of Production and Response to Pheromones
All of the pheromones described from pentatomoid adults to date are produced by male bugs (Table 15.1).
This pattern of pheromone emission by males, shared with diverse Coleoptera such as Curculionidae,
Chrysomelidae, and some Cerambycidae, may be correlated to males of these species being the risk-
taking sex that disperses to new habitats and locates new resources, especially in environments where
necessary resources are ephemeral in space and time (Aldrich et al. 1984, Millar 2005).
The response pattern to the male-produced pheromones is divided roughly equally between those that
appear to attract only females, and those that attract both sexes (and nymphs, when tested). Aggregation
pheromones are less obvious in function than sex pheromones, but ecologists have postulated several
fitness advantages associated with aggregation to produce densities higher than would occur without a
semiochemical signal (Wyatt 2014). First, mates may be easier to find at higher densities, which overlaps
with a strictly sexual function but also includes the phenomenon of attraction of males to signals of other
males, which also are attractive to females. This exploitation of the signals of others allows a cheating
male a chance to procure a mate without incurring the costs of producing and emitting pheromone (e.g.,
biosynthetic cost, becoming more apparent to natural enemies) (Wertheim et al. 2005, Cardé 2014). A
second possible driving force for formation and persistence of aggregations is the more efficient use of