684 Invasive Stink Bugs and Related Species (Pentatomoidea)
- and E. obscurus (Borges and Aldrich 1994), respectively. A non-stereoselective synthesis of
E. meditabunda pheromone 5 (Figure 15.2) started from cyclopropyl methyl ketone ( 6 ) and used the
Julia cyclopropane cleavage in three iterative steps to place all three methyl groups (Figure 15.2), in
a manner similar to syntheses of other methyl-branched bug pheromones (reviewed in Millar 2005).
Interestingly, the mixture of all eight possible stereoisomers represented by synthetic 5 was attractive to
female E. meditabunda in a Y-tube bioassay, demonstrating that the unnatural stereoisomers were not
inhibitory (Zarbin et al. 2012).
15.2.6 Eocanthecona furcellata (Wolff) [Pentatomidae: Asopinae]
Ho et al. (2003, 2005) investigated volatile compounds from metathoracic glands, dorsal abdominal
glands, and abdominal setae of the Asian generalist predatory stink bug Eocanthecona furcellata.
Metathoracic glands of both male and female bugs contained (E)-2-decenal as the major component with
lesser amounts of (2E, 4 E)-2,4-decadienal, (2E, 4 Z)-2,4-decadienal and (E)-2,9-decadienal. The amount
of (E)-2,9-decadienal in gland extracts from female E. furcellata was about five times higher than in
extracts from males, and, conversely, the amount of (2E,4Z)-2,4-decadienal was higher in males than
in females. (E)-2,9-Decadienal has been reported as an attractant for males of the anthocorid bug Orius
insidiosus (Say) (Aldrich and Puapoomchareon 1996). In E. furcellata, there was no sexual dimorphism
in the morphology of the dorsal abdominal glands of adults, even though their contents were different
between the sexes. Geraniol was found only in males, and limonene and α-terpineol were found only
in females, whereas linalool oxide isomers linalool, neral, and geranial were found in both sexes. The
dorsal abdominal gland contents of nymphs also were analyzed, with 4-oxo-(E)-2-hexenal, 4-oxo-(E)-
2-octenal, tridecane, and tetradecanal being major components. Male bugs but not females possessed
abdominal setae, and 6,10,13-trimethyltetradecyl isovalerate (stereochemistry not characterized) was
identified in extracts of the setae of males. Ho et al. (2005) investigated production of this male- specific
compound under various rearing conditions with the intriguing result that production was strongly
dependent on rearing density, decreasing over 100-fold as rearing density increased. This effect was par-
tially reversible and did not depend on the sex of the accompanying bugs. The density cues (e.g., tactile,
olfactory, or visual) that regulate production of the compound are not known (Ho et al. 2005).
15.2.7 Euschistus conspersus Uhler, Euschistus heros (F.), and Euschistus
servus (Say) [Pentatomidae: Pentatominae: Carpocorini]
The genus Euschistus consists of >80 species, and several are pests of tree fruit, tomato, soybean, cotton,
and other crops in the New World (McPherson and McPherson 2000). Species for which pheromones are
known fall into two distinct groups, one group based on methyl decadienoates, the other on trimethyltri-
decanoates (Millar 2005). Based on this knowledge, several practical advances have been made in these
bugs’ monitoring and management.
15.2.7.1 Euschistus conspersus: Pheromone-Based Monitoring
Aldrich et al. (1991) identified methyl (2E,4Z)-2,4-decadienoate as the major component of the aggre-
gation pheromone of the consperse stink bug, Euschistus conspersus. In tomato fields in California,
Cullen and Zalom (2005) discovered that responses of males and females differed by crop stage, and
that the onset of female-biased pheromone trap catches could be used as a biofix, which could then be
used to calculate degree-days to predict subsequent nymphal development in the field to optimally time
insecticide treatments targeting this susceptible stage (Cullen and Zalom 2006). Such models give grow-
ers of processing tomatoes more flexibility to use insecticides with lower risks of remaining residues at
harvest (Cullen and Zalom 2007). Krupke et al. (2001, 2006) attracted E. conspersus to pheromone-
baited mullein plants on the borders of apple orchards in Washington state, but efforts to trap the bugs
were not successful. These results, and similar results from other species, highlight the fact that over
shorter ranges, phytophagous stink bugs probably use substrate-borne vibrational signals rather than