Campylomma Reuter, 1878

Genus Campylomma Reuter, 1878 View in CoL

Campylomma Reuter, 1878: 52 View in CoL (n. gen.), type species: Campylomma nigronasta Reuter, 1878 , subsequent designation by Distant (1904); Schuh, 1995: 278 (catalog); Kerzhner & Josifov, 1999: 318 (catalog); Yasunaga, 2001: 156 (diagnosis); Schuh, 2003–2013 (online catalog); Konstantinov et al., 2015: 204 View Cited Treatment (discussion on diagnostic characters); Yasunaga et al., 2015: 51 (diagnosis): Yasunaga, 2016: 460 (diagnosis); Aukema, 2018 (online catalog); Yasunaga, 2021: 236 (diagnosis), 2022: 3–4 (checklist, key to genera).

Diagnosis: Asia-Oriental members of Campylomma are recognized by the following characters: body small, 1.5–3 mm in total length; coloration variable but generally pale green in most species; dorsum shining, uniformly covered with pale or brownish, simple vestiture often mixed with sparsely distributed, flat, lanceolate, reclining setae (cf. Fig. 6C, L View FIGURE 6 ); metafemur with a row of spinules along anterior margin ( Figs. 6F View FIGURE 6 ) and usually with dark spots at bases of trichobothria and spines ventrally ( Fig. 3A–F View FIGURE 3 , but absent in some congeners, e.g. C. aterrimum and C. flavipes ); all tibiae with brown to fuscous, long spines; pretarsus with setiform or weakly spatulate parempodia sometimes thickened apically ( Figs. 6G, N View FIGURE 6 , 8G, O View FIGURE 8 ); vesica with two (sometimes three or a single) apical blades and/or spicules, which are most useful character for species identification ( Figs. 4B, D–G View FIGURE 4 , 7C–D, I–J, O View FIGURE 7 ); female genital chamber with clear-rimmed sclerotized rings ( Figs. 5A, C, E View FIGURE 5 , 8M View FIGURE 8 ); and posterior wall of bursa copulatrix usually with densely distributed, sharp spinules anteriorly ( Fig. 7E, K View FIGURE 7 ). Further diagnostic characters and classification for the genus were discussed by Schuh (1984), Konstantinov et al. (2015) and Yasunaga (2021).

Distribution. Known widely from the Old World (tropics and subtropics in particular) and some Pacific Islands and Atolls; a single Nearctic species, Campylomma verbasci (Meyer-Dür, 1843) , is considered to have been introduced from Europe ( Yasunaga 2021).

Natural history. The majority of Campylomma species are considered zoophytophagous and propagate on variable dicot angiosperms (e.g. C. lividum and C. lividicorne , see checklist below). Although some species (including the two new species herein described and their allies) are host plant specific, their immature forms were found to have successfully developed into the adult stage when reared with a synthetic diet (macerated brine-shrimp eggs or red-worms, with diluted fermented milk beverage, cf. Fig. 2I View FIGURE 2 ) (cf. Fukuda et al. 2020; Miyazaki et al. 2020; Yasunaga unpublished observation). Some congeners (e.g. C. livida , C. verbasci ) are considered potential natural enemies against agricultural pests ( Wang 1995; Yasunaga 2001; Kijima et al. 2013; Jerinic-Prodanovic & Protić 2013).

As pointed out by Yasunaga et al. (2015, 2018), C. lividum , C. lividicorne and C. marjorae appeared to rapidly expand their distributions, possibly due to introductions with nursery stock of crops or ornamental plants. Recently, the East Asian temperate species, C. miyamotoi , was also found to have been introduced to Spain ( Goula & Mateos 2021) and Turkey (Çerçi1 et al. 2019).

Several congeners are known to inhabit cryptic niches or restricted vulnerable environments. For instance, C. asticum Yasunaga , C. hibiscicola Yasunaga and C. singapura sp. nov., were found only from sea hibiscus, Hibiscus tiliaceus (L.) ( Malvaceae ) ( Fig. 1E–F View FIGURE 1 ). All of these hibiscus-inhabiting members were observed to coexist with thrips, leafhoppers, aphids and/or psyllids, on which the mirids seem to predate ( Yasunaga 2021). More than a few predaceous mirid bugs as well as anthocorid bugs ( Anthocoridae ) were documented to share the same cryptic niches on coastal Hibiscus trees ( Yasunaga 2021; Yasunaga & Duwal 2022; Noguchi et al. 2023). The sea hibiscus, as implied by its name, is a halophilic broadleaf, and is indigenous to coastal zones which are considered the original habitat of these Campylomma species associated with Hibiscus tiliaceus .

On the other hand, C. marinum sp. nov. and C. salaciella are monophagous, restricted to the halophilic herb, Suaeda maritima (L.) Dumort. ( Amaranthaceae ) at seashores ( Fig. 1A–D View FIGURE 1 ). This vulnerable plant species is presently endangered or already extirpated at a number of maritime areas in Asia, having been seriously degraded by reclamation, concrete seawalls, and/or pollution (cf. Yasunaga & Shishido 2020). Therefore, effective environmental policies are urgently required to conserve the vulnerable halophyte communities as well as halophyte-inhabiting insects.

Updated checklist of Campylomma species known in the Oriental Region

(including species from Japan, Korea and Taiwan)

C. annulicorne (V. Signoret, 1865) — Distribution: China (Inner Mongolia), Japan (Hokkaido, N. Honshu), Korea, Russian Far East; Trans-Palaearctic— Host plant association: Salix spp. ( Salicaceae ).

C. asticum Yasunaga, 2021 — Japan (Okinawa Island), Taiwan (Taoyuan City)— Hibiscus tiliaceus planted at urbanized zones ( Yasunaga 2021).

C. atrum Schuh, 1984 — Philippines (Mindanao, Negros).

C. aterrimum Yasunaga, 2001 — Japan (Okinawa and Iriomote Islands)— Glehnia littoralis F. Schmidt ex Miq. ( Apiaceae ) (Yasunaga et al. 2015).

C. boharti Carvalho, 1956 — Japan (Ogasawara Islands).

C. boninense Carvalho, 1956 — Japan (Ogasawara Islands)—Both adults and immature forms were found from inflorescences of various herbs and broadleaf trees, such as Boehmeria densiflora var. boninensis (Nakai) Friis & Wilmot-Dear ( Urticaceae ), Glehnia littoralis , Leucaena leucocephala (Lam.) de Wit ( Fabaceae ), Trema orientale (L.) Blume ( Cannabaceae ) (Yasunaga unpublished data).

C.buddlejae Duwal,Yasunaga&Lee,2010 — Nepal (Kathmandu Valley)— Buddleja asiatica Lour. ( Scrophulariaceae ) ( Duwal et al. 2010).

C. chichijima Carvalho, 1956 , nomen dubium (cf. Yasunaga et al. 2015).

C. chitwanense Duwal, Yasunaga & Lee, 2010 —Central Thailand, Nepal (Terai).—Occasionally collected from inflorescences of various plants ( Asteraceae , Dipterocarpaceae and Tiliaceae ) but the breeding host is unknown ( Yasunaga & Duwal 2015).

C. eurycephalum Yasunaga, 2001 — Japan (Okinawa and Ishigaki Islands)—Collected from Hibiscus tiliaceus , but breeding host is yet to be found ( Yasunaga 2021).

C. flavipes Yasunaga, 2001 — Japan (Kyushu, Amami-Oshima and Tsushima Islands)— Glehnia littoralis .

C. fopingense Li & Liu, 2010 — China (Shaanxi).

C. fukagawai Yasunaga, Schuh & Duwal, 2015 — Japan (Honshu, Shikoku, Kyushu)— Albizia julibrissin Durazz ( Fabaceae ) (Yasunaga et al. 2015).

C. hibiscicola Yasunaga, 2021 ( Figs. 2H View FIGURE 2 , 8N–P View FIGURE 8 )— Thailand (Bangkok)— Hibiscus tiliaceus (planted at park).

C. koraticola Yasunaga & Duwal, 2015 —C. Thailand.

C. leyteanum Schuh, 1984 — Philippines (Leyte, Mindanao).

C. lividum Reuter, 1885 — Cambodia, SE China, India, Indonesia (Bali, Java), Japan (Honshu, Shikoku, Kyushu, Ryukyus, Ogasawara Isls., Tsushima Is.), S. Korea, Laos, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Taiwan, Thailand —Propagating on a variety of dicot angiosperms (cf. Yasunaga et al. 2015).

C. lividicorne Reuter, 1912 — Cambodia, India, Japan (Shikoku, Kyushu, Ryukyus), Korea, Myanmar, Nepal, Philippines, India, Singapore (new record), Thailand, Taiwan, Papua New Guinea —Propagating on various dicot angiosperms and often coexisting with C. lividum (cf. Yasunaga et al. 2015, 2018).

C. luzonicum Schuh, 1984 — Philippines (Luzon), Papua New Guinea.

C. malaysianum Schuh, 1984 — Malaysia ( Sarawak, Selangor).

C. marinum Yasunaga & Ito , sp. nov. — Japan (Kyushu)— Suaeda maritima .

C. marjorae Schuh, 1984 — Cambodia, India, Japan (Ishigaki Island, possibly due to recent introduction from Taiwan or SE Asia), Laos (new record), Myanmar, Nepal, Philippines, Solomon Islands, Sri Lanka, Taiwan, Thailand —Frequently found on inflorescences of various broadleaf trees, but the breeding host is yet to be confirmed (Yasunaga et al. 2015).

C. miyamotoi Yasunaga, 2001 — Japan (Honshu, Shikoku, Kyushu), South Korea, Spain (introduced, cf. Goula & Mateos 2021), Turkey (introduced, cf. Çerçi1 et al. 2019)— Albizia julibrissin , on which this species often coexists with C. fukagawai ( Yasunaga et al. 2018) .

C. monticola Poppius 1914 — Indonesia (Java), Philippines (Negros).

C. nanna Yasunaga & Duwal, 2015 — Laos, C. Thailand —The adults were found from Leucaena sp. ( Fabaceae ), but the breeding host is unknown ( Yasunaga & Duwal 2015).

C. nanrenanum Yasunaga, 2021 — Taiwan (Pingtung).

C. pimai Yasunaga & Duwal, 2015 —C. Thailand — Sesbania sp. ( Fabaceae ) [= Yasunaga & Duwal (2015) misspelled as ‘ Saebania’ sp.].

C. salaciella Yasunaga & Duwal, 2015 ( Figs. 2C–D View FIGURE 2 , 3C View FIGURE 3 , 4C–D View FIGURE 4 , 5C–D View FIGURE 5 , 6I–M View FIGURE 6 , 7G–L View FIGURE 7 )— Thailand (Chon Buri, Samut Prakan)— Suaeda maritima ( Figs. 1C–D View FIGURE 1 ).

C. seunghwani Yasunaga, 2016 —S. Thailand (Krabi, Phang Nga)— Macaranga indica Wight ( Euphorbiaceae ).

C. singapura Yasunaga, Yap & Hwang , sp. nov. — Singapore — Hibiscus tiliaceus .

C. tanakakianum Yasunaga, Schuh & Duwal, 2015 — Japan (Nagasaki Pref.).