56 Invasive Stink Bugs and Related Species (Pentatomoidea)
As Amyot and Serville (1843) and Schouteden (1907) perceived, there does appear to be a natural
dichotomy within the asopines. Although many of the genera are coarsely punctate and cryptically col-
ored in earth-tones (i.e., brown, tan, gray or black), about an equal number are glabrous and aposematic
(i.e., brightly colored or even metallic). There is circumstantial evidence that the bright colors are meant
to mimic the colors of the prey, typically chrysomelid beetles (van Doesburg 1970, Schaefer 1996);
this could be aggressive mimicry allowing the pentatomids to move closer to their prey without being
noticed, but it could also be a form of protective mimicry as both the pentatomids and the chrysomelids
probably taste bad to predators. But there is only weak support from the other character states that would
suggest that aposematic coloration is synapomorphic. Given the limited material at hand, it is likely that
Amyot and Serville’s concept of the “Asopides” was meant for the dull-colored forms and would be most
exemplified by Asopus argus (F.), [now Amyotea malabarica (F.)], which Bergroth (1911) argued should
be the type species for the asopines. This led to Leston’s (1953a) proposal to replace the subfamily name
with Amyotinae, which would have had as its nominate tribe Amyotini. But the oldest name for this tribe
is Armini, based on the genus Arma, as proposed by Bergroth (1904), leaving the nominate tribe Asopini
typified by the genus Discocera.
The most striking apomorphy in the group is the presence of a pair of pilose glands on the abdominal
sternum of males. It has been shown that this gland secretes an aggregative pheromone that is released
when the males find prey. This attracts other members of the species including potential mates (Aldrich
1988, Aldrich and Lusby 1986). Of the 62 genera for which males are known (Australojalla Thomas
is known from a single female), 23 have the abdominal glands. The glands are present in Afrius Stål
(except the subgenus Subafrius Schouteden), Andrallus Bergroth, Apateticus Dallas, Apoecilus Stål,
Blachia Wa l ker, Bulbostethus Ruckes, Canthecona, Cazira Amyot and Serville, Coryzorhaphis Spinola,
Discocera, Eocanthecona Bergroth, Heteroscelis Latreille, Hoploxys Dallas, Leptolobus Signoret,
Macroraphis Dallas (except the subgenus Megarhaphis W h ite), Mecosoma Dallas, Montrouzierellus
Kirkaldy, Oplomus Spinola, Perillus, Platynopiellus Thomas, Platynopus Amyot and Serville, Stilbotes
Stål, and Stiretrus. Because of its complexity, function, and, most importantly, the constant nature of its
morphology among genera, there is little likelihood that its presence is the result of convergence rather
than relationship. Its absence in two subgenera of genera that possess them would be explainable as a
secondary loss. Because the above 23 genera include Asopus, they would constitute the nominotypical
tribe Asopini.
Species with reduced or suppressed glands are known at least in the genera Afrius, Cazira (Figure
2.27B), and Macroraphis. This indicates that the glands could have been lost multiple times. The
non-glandular genera would constitute a sister clade, an arrangement consistent with the dichotomy
envisioned by early workers, Amyot and Serville (1843), Schouteden (1907) and Bergroth (1904, 1911).
But, inasmuch as it is defined by a plesiomorphy, the resulting clade, functionally the Armini, may
well be polyphyletic. Within this group, a second tribe has been proposed by Dupuis (1949). The
Jallini was erected to include Jalla Hahn and Zicrona Amyot and Serville, but there is no reason to
suspect that Jalla and Zicrona are related. Dupuis cited the extension of the seventh abdominal ter-
gite; however, the extension is found also in the genus Dorycoris Mayr, which shares no apomorphic
characters with either of the two genera included by Dupuis and thus there is minimal support for the
tribe as proposed. We suspect that Jalla more likely is related to the genera Amyotea, Anasida, and
Pseudanasida Schouteden (but not Jalloides Schouteden or Australojalla) based on a similarly broad
but flattened body form and the scent-gland ruga is gutter-like. Without a formal phylogenetic analy-
sis to define its relationships, we consider that Dupuis’ Jallina is no more than a subclade of Armini,
moreover with Zicrona excluded.
Similarly, within the clade of male-gland possessing genera, the monotypic tribe Stilbotini has been
proposed by Gapud (2015) based on Stilbotes, from the Philippines. Based on a suite of shared charac-
teristics, Stilbotes is related to the African genus Leptolobus. Both genera have pedunculated eyes distant
from the cervix (i.e., a membranous area between the head and thorax), a bilobed thorax, and spinous
humeri. Both genera also have the male abdominal glands and therefore fall within the Asopini; thus,
Stilbotini is probably a subclade of the latter tribe. Until a formal phylogenetic analysis can confirm its
validity, we propose that Gapud’s name should be treated as a synonym of the Asopinae, being a subclade
of Asopina, including Leptolobus.