Semiochemistry of Pentatomoidea 685
volatile pheromones to locate conspecifics once they are on the same plant (Millar 2005). Thus, volatile
pheromones may effectively attract bugs to the vicinity of a pheromone lure but may not induce bugs to
enter traps.
15.2.7.2 Euschistus heros: Effects of Food on Pheromone
Emission, and Pheromone-Based Monitoring
Moraes et al. (2008c) held 9-day-old E. heros males under 4 regimes: supplied with green beans, sup-
plied with water only, held in humidified air, or held in dry air. During the following week, bean-fed
bugs released all three pheromone components in the ratio reported by Zhang et al. (2003) for all seven
days. In contrast, insects without food stopped releasing methyl 2,6,10-trimethyltridecanoate and methyl
2,6,10-trimethyldodecanoate after one day, only continuing emission of methyl (2E,4Z)-2,4-decadienoate,
demonstrating the importance of diet as a strong influence on pheromone production and blend.
Borges et al. (2011) found that a transparent trap fitted with lures containing 1 mg of the Euschistus
heros sex pheromone component methyl 2,6,10-trimethyltridecanoate (as a stereoisomeric mixture) was
more effective and less time-consuming than the beat-cloth technique in monitoring soybean infestation
by E . heros in central Brazil. Borges et al. (2011) also caught Edessa meditabunda and Piezodorus guildinii
in the same traps, at >10% of total captures, but statistical comparisons to unbaited traps were not reported.
15.2.7.3 Euschistus servus: Use of Pheromone in Trap Crop
Tillman and Cottrell (2012) tested the effectiveness of a trap crop of grain sorghum, with and without
pyramidal traps baited with methyl (2E,4Z)-2,4-decadienoate, for preventing movement of E. servus
from corn and peanut fields into cotton crops in Georgia, United States. Although the trap crops reduced
movement into cotton, the presence of the pheromone traps had no effect on the efficacy of the trap crop.
15.2.8 Eysarcoris lewisi (Distant) [Pentatomidae: Pentatominae: Eysarcorini]
Eysarcoris lewisi is one of the major pests of rice in northern Japan (Kiritani 2007). The possibility of
using pheromone-baited traps for monitoring E. lewisi was examined by Takita (2007), who found that
males reared under a long-day photoperiod attracted adults of both sexes and nymphs to water-pan traps
in the field, in contrast to short-day males, which did not attract conspecifics. Mori (2007) demonstrated
the pheromone to be either (2Z,6R,1′S,5′S)- or (2Z,6R,1′R,5′R)-2-methyl-6-(4’-methylenebicyclo[3.1.0]
hexyl)hept-2-en-1-ol by synthesis and bioassay of four diastereomeric mixtures of isomers. Takita et al.
(2008) isolated the pheromone and confirmed its attractiveness to both sexes and nymphs of E. lewisi in
field trials. These workers also determined that the pheromone had the (2Z)-configuration from NMR
spectra. Mori et al. (2008) and Tashiro and Mori (2008) then determined its absolute configuration to
be (2Z,6R,1’S,5’S)-2-methyl-6-(4’-methylenebicyclo[3.1.0]hexyl)hept-2-en-1-ol ( 10 ) by syntheses of indi-
vidual stereoisomers, using an enzyme-based kinetic resolution of an intermediate in a key step in the
syntheses, shown in Figure 15.3.
Thus, (R)-citronellal was converted in several routine steps into diazo compound 14. Reaction of 14
with copper and copper salts produced a carbene that intramolecularly inserted into the terminal alkene,
producing bicyclic ketone 15. Reduction of ketone 15 produced alcohols 16 and 17 , which were subjected
to Lipase PS-D catalyzed acetylation, whereupon only 16 was acetylated to yield acetate 18. The acetate
18 and unreacted alcohol 17 were then readily separated and converted to 19 and 20 resp e ct ively, t he
absolute configurations of which were determined by circular dichroism spectroscopy (Mori et al. 2008,
Tashiro and Mori 2008). The conversion of ketone 20 to the final product 10 involved several steps, includ-
ing Ando’s Z-selective olefination (Ando 1998), producing stereoisomer 10 in 3.3% overall yield from
(R)-citronellal. This isomer matched the compound produced by E. lewisi (Tashiro and Mori 2008). These
authors reported that the LiB(sec-Bu) 3 H (L-Selectride®) reduction of the diastereomeric mixture of ketones
15 strongly favored (>95%) delivery of the hydride from the face opposite the cyclopropane ring to avoid
steric hindrance (Tashiro and Mori 2008). However, when Khrimian et al. (2011) used the same conditions