696 Invasive Stink Bugs and Related Species (Pentatomoidea)
produced the pheromone (mean 40 ng/day) from morning through evening, females only responded dur-
ing the evening (1700-2000 h). The compound was identified as (6S,7R)-(+)-β-sesquiphellandrene ( 63 ),
the general structure of which was confirmed by comparison with an authentic standard by GC-MS.
The absolute configuration was determined by: (1) conversion to α-curcumene 64 and comparison of
its GC retention time on a chiral Cyclodex-B column with those of standards prepared by dehydroge-
nation of (-)- and (+)-β-sesquiphellandrene; and (2) hydrogenation to a bisabolane 65 and analysis on a
Cyclodex-B column along with authentic standards (McBrien et al. 2002) (Figure 15.12). It is notewor-
thy that β-sesquiphellandrene produced by P. guildinii has the opposite configuration to the (6R,7S)-β-
sesquiphellandrene present in ginger oil and also is produced as a pheromone component by two other
stink bug species, Thyanta pallidovirens and Thyanta custator accerra (McBrien et al. 2002).
15.2.14.2 Aggregation Pheromone of Piezodorus hybneri: Functions and Variation
Piezodorus hybneri is a major soybean pest in southern Japan. Leal et al. (1998) identified the pher-
omone blend and showed that both males and females were attracted to the 3-component blend of
β-sesquiphellandrene, (R)-15-hexadecanolide, and methyl (Z)-8-hexadecenoate (ratio: 10:4:1). Males “also
displayed a clear precopulatory behavior,” even eliciting male-male sexual behavior. Leal and coworkers
argued that this pheromone therefore functioned primarily as a sex pheromone rather than an aggregation
pheromone. In field trials, the pheromone blend attracted predominantly females, and the individual com-
ponents were not attractive (Endo et al. 2010). The pheromone attracted similar numbers of both sexes late
in the fall, even though males would not be expected to produce it at this time (Endo et al. 2010). Endo et
al. (2007, 2012) also studied the effects of age and diapause on pheromone emission by male P. hybneri.
Only non-diapausing males produced pheromone; production started 3-6 days after adult emergence, was
quantitatively and qualitatively different from individual to individual, and also changed within individu-
als over time. This led Endo et al. (2012) to question whether it was realistic to consider that the phero-
mone consisted of a set ratio of components. Whereas other studies have shown variation in pheromone
component ratios in stink bugs (e.g., Miklas et al. 2000, for Nezara viridula), this is the only study to date
that demonstrates changes in pheromone emission over the lifetime of individual bugs.
- 2 .14. 3 Attraction of Piezodorus hybneri to the Pheromone of Riptortus
clavatus Thunberg (Heteroptera: Coreoidea: Alydidae)
It was discovered serendipitously in field trials that Piezodorus hybneri was attracted to one component,
(E)-2-hexenyl (E)-2-hexenoate, of the 3-component pheromone of Riptortus clavatus, even though
P. hybneri does not produce this compound (Endo et al. 2006, Huh et al. 2006). The R. clavatus component
appeared to be most attractive to unfed adults of both sexes, suggesting a kairomonal role in plant host
finding (Endo et al. 2010). It was also attractive to nymphs (Endo et al. 2010). The pheromone of P. hybneri
and (E)-2-hexenyl (E)-2-hexenoate were not tested together.
15.2.15 Plautia stali Scott [Pentatomidae: Pentatominae: Antestiini]
The brown-winged green stink bug, Plautia stali, is a serious pest of tree fruits in Asia and also was
discovered in Hawaii in 1967 (Mau and Mitchell 1978). The male-produced aggregation pheromone,
HH64 63 65FIGURE 15.12 Sex pheromone of Piezodorus guildinii, (6S,7R)-(+)-β-sesquiphellandrene ( 63 ) correlated to curcumene
64 and bisabolane 65.