Pilophorus Hahn

Yasunaga, Tomohide, Yamada, Kazutaka & Artchawakom, Taksin, 2014, Additional records and descriptions of the ant-mimetic plant bug genus Pilophorus from Thailand (Hemiptera: Heteroptera: Miridae: Phylinae: Pilophorini), Zootaxa 3795 (1), pp. 1-15 : 3

Genus Pilophorus Hahn

Diagnosis. Primarily recognized by more or less myrmecomorphic, elongate and always macropterous body form; partly aggregated scalelike setae on scutellum; presence of anterior band of scalelike setae on corium (a posterior band variable, sometimes interrupted or scattered); weakly or moderately flattened metatibia; fleshy, recurved, apically convergent parempodia; usually strongly sprayed-out left paramere; ovoid to elongate oval right paramere; and C- to J-shaped (but rarely nearly straight) endosoma often furnished with a median spine, flagellum or barb. Some species strikingly ant-like because of strong modifications of the pronotum that is conspicuously tightened, constricted, or horned ( Fig. 3 ). Schuh (1984, 1991), Schuh & Schwartz (1988) and Yasunaga & Schuh (2013) provided further diagnostic characters and synapomorphies.

Distribution. Holarctic, Oriental and Afrotropical regions, New Guinea, and some Pacific islands.

Biology. Most members of Pilophorus appear to be host plant specific, and the host plants range from forbs, broadleaf woody angiosperms to conifers, but the genus is also assumed to comprise predators, preying on other arthropods ( Wheeler, 2001; Yasunaga, 2001; Yasunaga & Schuh, 2013). In Japan, P. t y pi cu s (Distant) and its closely related congeners are regarded to be potential candidates as indigenous natural enemies for biological control programs ( Ito et al., 2011; Yasunaga, 2001). Both adults and immature forms are often observed to co-occur with the workers of various ants.

Discussion. Most members of Pilophorus are assumed to have strong relationships to certain ant species ( Nakatani et al., 2013; Yasunaga & Schuh, 2013), and quite a few undescribed species exist particularly in the subtropical and tropical Old World. There are at least three undetermined or undescribed species (now represented only by females, as in Fig. 1 H) present in Thailand. We refrain from describing such species until male specimens are available.

Pilophorus comprises morphologically very diverse species; some members are strikingly antlike ( Fig. 3 ) because of conspicuous modification of the pronota, and P. portentosus , which has the excessively long antennae and legs ( Fig. 3 H), resembles wasp rather than ant ( Yasunaga & Schuh, 2013). On the other hand, Nakatani et al. (2013) reported seven unique species that are predominantly associated with Macaranga trees ( Euphorbiaceae ) in Malaysia; these members uniquely have the strongly protruded scutella. In spite of such great interspecific variation exhibited in some special members, the monophyly of the genus may be supported by the recent phylogenetic analyses based on both morphology and DNA sequence data ( Schuh & Menard, 2011; 2013).

Figures

FIGURE 1. Habitus images of Pilophorus spp., living individuals. A & B. P. suwimonae, holotype male (AMNH _ PBI 00380149). C. P. subparallelus, male (00380162). D. P. meteorus, holotype male (00380150). E. Same, female (00380152). F. P. typicus, male (00380192). G. Same, 5 th instar immature (from SERS). H. Undetermined species, female (SERS).

FIGURE 3. Habitus images of ‘ strikingly’ antlike (A − D) or otherwise morphologically novel (E) members of Pilophorus, living adult individuals named on the figure.