This document summarizes a study on the phylogeny of predatory stink bugs in the subfamily Asopinae. The analysis recovered the monophyly of Asopinae, which was supported by 16 synapomorphies. Eighteen of the 19 genera included in the analysis with multiple species were monophyletic, while the genus Podisus was paraphyletic. The pseudoclaspers found in males may have contributed to the evolutionary success of Asopinae by enhancing copulatory performance compared to other pentatomids.

1. Phylogeny of the predatory stink bugs
(Hemiptera: Pentatomidae: Asopinae)
Talita Roell & Luiz Alexandre Campos
tali.roell@gmail.com
luiz.campos@ufrgs.br

2. Asopinae is a group of predatory stink bugs very
variable in color, size and shape occurring worldwide
and currently classified in 65 genera and 300 species.
Its species are characterized, mainly, by the apparently rectangular head, and by
the robust labium modified for predation, which makes them potential
controllers of diverse agricultural pests worldwide .
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The males in 27 genera have
pheromone-producing
abdominal glandular
patches
The males have a pair of pseudoclaspers in the
pygophore
And the phallotheca is divided in basal and apical
theca
Its monophyly was many times speculated but never tested with a phylogenetic method

3. Material and methods
The data matrix with 154 morphological characters and 103 taxa was constructed in the software
Mesquite v. 3.10. The ingroup is composed by 89 species.
Character polarization followed the outgroup method and the most parsimonious trees were
searched in TNT under implied weighting (IW).
The outgroup includes most subfamilies of Pentatomidae (Cyrtocorinae, Discocephalinae,
Edessinae, Pentatominae, Phyllocephalinae, and Podopinae).
The IW analyses were performed according to Mirande (2009), with default settings of his script, to 11 K-values calculated with
a fit range of 50% to 90% of a perfectly hierarchical character. Strict consensus trees were calculated for each K-value. A
similarity matrix of Subtree Pruning Regrafting (SPR) distances was constructed to compare the 11 strict consensus of the K-
values. The presented classifications under implied weighting are based on the trees with higher sums of similarity of SPR
distances, indicating more stable K-values.
Relative Bremer support values (subtrees up to ten extra steps; relative fit difference of 0.9) were calculate.
The frequency of each clade recovered in the 11 consensus trees was calculated with the respective K-values in TNT.
We present the first phylogenetic analysis for Asopinae.

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The cladistic analysis recovered the monophyly of
Asopinae in the most parsimonious trees for the fifth K-
value (K4= 11.737) (Fit =61.56217; L= 1865; Ci= 11; Ri=
50)
The Asopinae clade is supported by sixteen
synapomorphies, three out of them non-homoplastic:
valvifers IX trapezoidal elongated,
ring sclerites absent or reduced, and
presence of pseudoclaspers
Asopinae was recovered sister to Murgantia varicolor
(Pentatominae: Strachiini).
Eighteen out of the 19 genera of Asopinae with more
than one representative species included in the analysis
were recovered monophyletic, whereas Podisus was
recovered paraphyletic

5. - Although many authors have raised doubts about the group's
monophyly, this is the first time the monophyly of the subfamily
was tested under an explicit phylogenetic method
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Support:
- Despite predation is not unique for the asopines among
Heteropterans, the modifications related to feeding on insects
may have allowed the evolutionary success of Asopinae
within Pentatomidae.
Main references:
Gapud, V.P. (1991) Philippines Entomology, 8(3), 865–961.
Mirande, J.M. (2009) Cladistics, 25, 574–613
Roell, T et al. (2020) Arthropod Structure & Development, 100946 and 100949
Thomas, D.B. (1992) Taxonomic synopsis of the Asopine Pentatomidae …
Thomas, D.B. (1994) Insecta Mundi, 8, 145–212.
- The pseudoclaspers may have contributed to the
evolutionary success of the subfamily, since they
probably have a differential copulatory performance
compared with the other pentatomids
- Despite the cladistic analysis had resulted in many
monophyletic clades for Asopinae we did not find
sufficiently distinctive and congruent features to
divide Asopinae in tribes.