682 Invasive Stink Bugs and Related Species (Pentatomoidea)
B. hilaris feeds primarily on plants in the Brassicaceae (mustard family) and Capparaceae (caper family)
and is extremely damaging to cole crops, bok choi, and capers (Guarino et al. 2008, Reed et al. 2013,
Biovision Foundation 2014). Guarino et al. (2008) studied possible volatile and contact pheromones that
might mediate mating behaviors. In Y-tube bioassays, female B. hilaris were attracted to odors from
males and also to a hexane extract of volatile compounds collected from males, whereas odors of females
did not attract either gender. GC-MS analyses showed that both males and females produce nonanal,
decanal, and (E)-2-octenyl acetate, the latter produced in substantially higher quantities by males than
females. Thus, (E)-2-octenyl acetate was suggested to be a long-range mate-location pheromone, but to
date, results of field bioassays have not been published. Interestingly, in the alydid bug Leptocorisa chi-
nensis, a blend of (E)-2-octenyl acetate and octanol is also produced by both sexes but is attractive only
to males (Leal et al. 1996).
In studies of possible short-range or contact pheromones using open arena bioassays, males displayed
characteristic courtship behaviors in the presence of virgin females (Guarino et al. 2008). Courtship
behavior also was displayed in response to females killed by freezing, but not to freeze-killed females
washed with hexane, suggesting a nonpolar contact pheromone in the cuticular lipids. De Pasquale et al.
(2007) identified thirteen homologous cuticular n-alkanes (nC 17 - nC 29 ) from both sexes. The hydrocarbon
profiles of males and females were qualitatively similar, but marked sex-specific quantitative differences
were observed for some of the components, which were suggested to be involved in mate recognition
(De Pasquale et al. 2007). However, bioassays with pure compounds or blends of compounds have not
yet been reported.
15.2.3 Chinavia hilaris (Say), Chinavia ubica (Rolston), and Chinavia
impicticornis (Stål) [Pentatomidae: Pentatominae: Nezarini]
Blassioli-Moraes et al. (2012) found that males of two sympatric neotropical stink bug species, Chinavia
ubica and C. impicticornis, both produced epoxybisaboladienes, which attracted conspecific females
in laboratory assays. Diastereomeric (2S,3R,6S,7Z)-2,3-epoxy-7,10-bisaboladiene ( 1 ) and (2R,3S,6S,7Z)-
2,3-epoxy-7,10-bisaboladiene ( 2 ) had been identified previously as sex pheromone components for
C. hilaris (= Acrosternum hilare) and Nezara viridula (L.) with different ratios of 1 and 2 providing species
specificity (reviewed in Millar 2005). Microprobe NMR spectra of volatiles from male C. ubica showed
that they produced a 9:1 mixture of 1 and 2 , whereas C. impicticornis emitted almost exclusively epoxide
2 (Figure 15.1).
The absolute configurations of epoxides 1 and 2 were established by oxidative cleavage to 4-acetyl-
1,2-epoxy-1-methylcyclohexanes 3 and 4 followed by comparison of their retention times on a chiral
stationary phase β-DEX GC column with those of standards synthesized from commercially available
(-)- and (+)-limonenes (Blassioli-Moraes et al. 2012). Interestingly, bioassay data suggested that the abso-
lute configurations of the epoxides appeared to be less important for conspecific recognition than the
relative configurations.
Chinavia hilaris also represents an example of a species that is attracted to a compound that it does
not produce but which is a pheromone of another stink bug species. Thus, Aldrich et al. (2007, 2009)
demonstrated that C. hilaris was attracted to methyl (2E,4E,6Z)-2,4,6-decatrienoate, and that this attrac-
tion was even stronger than that to the 95:5 blend of epoxides 1 and 2 identified as the natural pheromone
blend of this species (McBrien et al. 2001). Tillman et al. (2010) confirmed this cross-attraction although
O1234O OOOOFIGURE 15.1 Chinavia ubica and Chinavia impicticornis sex pheromone components 1 and 2 , and products of cleavage
thereof, 3 and 4 , used to determine the absolute configurations of 1 and 2.