Semiochemistry of Pentatomoidea 707
15.4.3 Pentatomid Compounds as Kairomones for Arthropod Predators
Millar et al. (2001) reported that Astata occidentalis (Cresson), a predatory sphecid wasp that provisions
its nest with stink bugs, was attracted to the sex pheromone of Thyanta pallidovirens. In field experi-
ments, only female wasps were caught in traps baited with methyl (2E,4Z,6Z)-2,4,6-decatrienoate, the
main pheromone component of T. pallidovirens, and blends of this compound with the sesquiterpenoid
minor components of the pheromone (zingiberene, sesquiphellandrene, and α-curcumene) (Millar et al.
2001). Recently, Cottrell et al. (2014) caught substantial numbers of A. occidentalis in traps baited with
the Plautia stali pheromone, methyl (2E,4E,6Z)-2,4,6-decatrienoate, deployed to monitor Halyomorpha
halys and other pentatomids in Georgia and Washington state, United States. The authors noted that this
could have been due to isomerization of methyl (2E,4E,6Z)-2,4,6-decatrienoate to the Thyanta pher-
omone, methyl (2E,4Z,6Z)-2,4,6-decatrienoate (Khrimian et al. 2008), or it may be that the wasp is
attracted to several of the isomers of this compound.
Aldrich et al. (1986a) found that yellowjacket wasps (Vespula maculifrons (Buysson) (Hymenoptera:
Vespidae)) were attracted to synthetic pheromone mixtures for Podisus spp., as were honey bees (Apis
mellifera L.), which may have been incidentally attracted because the Podisus pheromone contains com-
ponents also found in floral volatiles. Aldrich and Barros (1995) demonstrated attraction of male crab
spiders Xysticus ferox (Hentz) (Araneae: Thomisidae) to (E)-2-octenal and (E)-2-decenal, but suggested
that this probably represented semiochemical overlap with a putative spider sex pheromone rather than
any indication of kairomonal prey detection.
15.4.4 Predatory Stink Bugs Exploiting Semiochemicals of Their Prey
Several predatory stink bug species (Asopinae) have been studied in relation to semiochemically medi-
ated interactions with their prey and the prey’s host plants. For example, Yasuda (1997) showed that
Eocanthecona furcellata was attracted to volatiles, including several saturated hydrocarbons, from cat-
erpillars of its noctuid prey Spodoptera litura (F.). Conversely, in a recent study, larvae of the Colorado
potato beetle, Leptinotarsa decemlineata Say, were shown to reduce their feeding when predatory
Podisus maculiventris were present. The evidence suggested that this effect was mediated by olfaction
and, to a lesser extent, visual cues (Hermann and Thaler 2014). The effect was stronger for male bugs,
leading the authors to suggest that application of the male-produced P. maculiventris aggregation phero-
mone might be useful in indirectly reducing pest feeding damage, in addition to recruiting predatory
bugs (Hermann and Thaler 2014).
15.4.5 Tritrophic Interactions Involving Pentatomoid Bugs
Tritrophic interactions with Pentatomoidea may involve several different scenarios, with stink bugs
being either the top level (predator), or the middle level (prey). Plants produce a great diversity of volatile
and nonvolatile compounds, some of which are induced by herbivores. Both constitutive and induced
phytochemicals influence herbivores directly in terms of host preference and feeding choices, and indi-
rectly through attraction of their natural enemies (Poelman et al. 2008). Such “herbivore-induced plant
volatiles” (HIPVs) have been suggested to be exploited by predators and parasitoids to locate prey or
hosts, respectively, because these induced volatiles are reliable indicators of host presence, and because
these compounds may be emitted in much higher amounts than volatiles from the herbivore itself (Vet
and Dicke 1992).
The predatory bug Perillus bioculatus (F.), which specializes on chrysomelid beetles, is attracted to
plant volatiles induced by Colorado potato beetle, Leptinotarsa decemlineata, feeding on potato, and
less strongly to volatiles induced by mechanical damage to the plant (van Loon et al. 2000; Weissbecker
et al. 1999, 2000). Two generalist predatory pentatomids, Podisus maculiventris and P. nigrispinus
(Dallas), also are attracted to herbivore-induced plant volatiles (Sant’Ana and Dickens 1998, Greenstone
and Dickens 2005). In a recent field study of potential tritrophic interactions, Kelly et al. (2014) tested
responses of Podisus maculiventris to lures releasing either methyl salicylate (an herbivore-induced plant
volatile) or P. maculiventris aggregation pheromone. The pheromone enhanced retention of bugs, but