Bilia Distant, 1904

Yasunaga, Tomohide, Yamada, Kazutaka, Soe, Zayar & Naing, Shine Shane, 2016, First records of two flower bug genera from Myanmar (Hemiptera: Heteroptera: Anthocoridae: Anthocorinae: Oriini), with description of a new species of Bilia, Zootaxa 4158 (4), pp. 544-556 : 546

Genus Bilia Distant, 1904

Bilia Distant, 1904: 480 (in Miridae ) (type species by original designation: B. fracta Distant, 1904 ); Carayon (1958: 154, 159) (transferred to tribe Oriini of Anthocoridae ); Carayon & Miyamoto (1960: 20−26) (redesc.); Péricart (1996: 121) (cat.); Yasunaga (2000: 353) (diag.); Yasunaga (2001: 284) (diag.); Bu & Zheng (2001: 177) (diag.).

Biliola Carvalho, 1951: 386 (in Miridae ), type species by monotypy: Biliola castanea Carvalho, 1951 (synonymized by Carayon & Miyamoto 1960: 25); Carayon (1958: 160) (transferred to tribe Oriini of Anthocoridae ).

Diagnosis. Distinguished from other anthocorid genera by the following combination of characters: rounded, tortoise-shaped body; basic coloration brown to fuscous; shiny dorsal surface with uniformly distributed, wooly, reclining or semi-erect setae; short and widened head; male paramere C- or J-shaped, slender, apically tapered and accompanied by a median, small, slender projection ( Figs. 24−25, 27 ) that is homologous with ‘flagellum’ in Orius ( Fig. 31 ) and Wollastoniella ( Figs. 33−34 ); female copulatory tube fragile, totally membranous ( Fig. 26 ). The immature form has a fuscous, rounded, hemispheric body ( Fig. 6 ). Detailed generic characters were provided by Carayon & Miyamoto (1960).

Distribution. Known from the Oriental and eastern Palearctic regions; currently recorded from China, India, Japan, Myanmar, Taiwan, and Russian Far East.

Discussion. This genus is closely related to Wollastoniella , from which it may be separated only by the genitalia; the diagnostic features were argued extensively by Carayon (1958) and Carayon & Miyamoto (1960). Bu & Zheng (2001) and Carayon (1958) suggested the general body shape and puncture pattern on the pronotum as key diagnostic characters; however, these external characters are now found not to be applicable to every species. In addition, the immature forms of Bilia and Wollastoniella species exhibit totally similar (or fundamentally identical) shape (cf. Figs. 6 and 17 ).

Bilia is posited to be composed of Asian elements, based on the distribution patterns of the nine known species from India and Sri Lanka to Java, the Sundaland ( Carayon 1982) and the Pacific Islands ( Yasunaga 2000); more than a few undescribed species have also been found in Peninsular Malaysia, Nepal and Thailand (Yamada & Yasunaga, unpublished data). In the Oriental Region including the Himalayan area, both Bilia and Wollastoniella are known ( Bu & Zheng 2001). Although the latter genus occurs in Africa ( Carayon 1958; Ghauri 1987), the two genera are most probably derived from a lineage (cf. Figs. 32–34 , B) once present in the Himalayan region where many Asian organisms are assumed to have originated. To demonstrate this hypothesis, however, further broader surveys on the characters are required, which is beyond the scope of this work.

Members of the genus appear to be predaceous as evidenced by B. esakii and B. japonica that have been observed preying on typhlocybine leafhoppers and/or psyllids ( Yasunaga 2001). Carayon & Miyamoto (1960) also documented that B. japonica preyed on the eggs and nymphs of cicadellid leafhoppers, and B. castanea was reported as a natural enemy of Lipaphis erysimi (Kaltenbach, 1843) (Aphididae) which is injurious to black mustard, Brassica nigra L. (Brassicaceae) ( Ghosh et al. 1981). These observations suggest that Bilia species may prefer hemipterous insects rather than thrips which are generally preferred by Wollastoniella species.

Figures

FIGURES 24 − 28. Male (24 − 25, 27 − 28) and female (26) genitalia of Bilia castanea (24), B. burma n. sp. (25 − 26), B. pilosa Yasunaga (from Japan) (27), and Wollastoniella rotunda (28), named on the figures.

FIGURE 29 − 35. Schematic lineages shown with male parameres and female copulatory tube (29, 31 – 34) of five representative genera. 29, Kitocoris hahajima Yasunaga (redrawn from Yasunaga 2000). 30, Montandoniola pictipennis (Esaki) (from Ya mada et al., 2010 b). 31, Orius minutus (L.) (from Yasunaga 1997 b). 32, Bilia burma n. sp. 33, Wollastoniella parvicuneis Yasunaga (from Yasunaga 1995). 34, W. rotunda Miyamoto & Yasunaga (from Miyamoto & Yasunaga 1993). 35, Hypothesized intermediate condition between Bilia and Wollastoniella. Scale bars 0.05 mm.

FIGURES 1 − 7. Bilia burma, habitat, habitus images and a tingid co-occurring in same niche. 1, Adult female (arrowed) of Bilia burma on Ziziphus mauritiana Lam. 2, Bilia burma, female adult. 3, Ditto, male. 4, Ditto, male (left) and female adults (center), with a coccid (right). 5, Ditto, male adult. 6, Ditto, fifth instar nymph. 7, Monosteira sp. (Tingidae). All images taken on Oct 17, 2015.

FIGURES 14 − 19. Wollastoniella rotunda, habitat (14), habitus images (15 − 17), a leafhopper (18) and a tingid (19) cooccurring in same niche. 14, Wollastoniella rotunda, adult female (arrowed) on Urena lobata L. 15, Ditto, male adult. 16, Ditto, female adult. 17, Ditto, fifth instar nymph. 18, A typhlocybine leafhopper (Delphacidae: Typhlocybinae). 19, Haedus sp. (Tingidae: Tinginae). All images taken on Sep 28, 2015.