Cavariella (Cavaraiellia) aquatica (Gillette & Bragg, 1916)

Xu, Ying, Chen, Jing, Jiang, Li-Yun & Qiao, Ge-Xia, 2023, Cavariella Del Guercio (Hemiptera, Aphidinae, Macrosiphini) in China, with a new species, new synonymies, and first country records, ZooKeys 1169, pp. 235-292 : 235

Cavariella (Cavaraiellia) aquatica (Gillette & Bragg, 1916)

Figs 1 , 2 , 32A-C

Siphocoryne aquatica Gillette & Bragg, 1916: 447.

Types examined.

Holotype and paratypes of Cavariella cessana Zhang, Chen, Zhong & Li, 1999: one ap. viv. fem. and one ala. viv. fem., China: Xinjiang (Korla City), 19.VI.1989, No. 9391, on Salix , coll. G.X. Zhang and T.S. Zhong ( Zhang et al 1999).

Other specimens examined.

One ap. viv. fem., Tibet (Xigaze City), 17.VII.2022, No. 51892-1-1, on Salix , coll. Y. Xu ; one ap. viv. fem.; Tibet (Xigaze City), 26.VII.2014, No. 32740-1-1, on Salix , coll. J. Chen and X.C. Zhu ; one ap. viv. fem., Tibet , 23.VI.2016, No. 37396-1-1, on Salix , coll. F.F. Niu ; one ap. viv. fem. and one ala. viv. fem., Tibet (Linzhi City), 23.VI.2014, No. 37394-1-1, on Salix , coll. F.F. Niu ; one ap. viv. fem. and one ala. viv. fem. (slides), one ap. viv. fem. (COI: OP956122 ), Tibet (Xigaze City), 26.VII.2014, No. 32744-1-1, on Salix , coll. J. Chen and X.C. Zhu ; one ap. viv. fem., Tibet (Xigaze City), 16.VII.2014, No. 32664-1-1, on Hordeum vulgare var. coeleste , coll. J. Chen, X.C. Zhu, X.H. Lou ; two ap. viv. fems. (slides) and one ap. viv. fem. (COI: OP956121 ), Tibet (Xigaze City), 26.VII.2014, No. 32742-1-1, on Hordeum vulgare var. coeleste , coll. J. Chen, X.C. Zhu, X.H. Lou ; one ap. viv. fem. and one ala. viv. fem., Tibet (Linzhi City), 23.VI.2016, No. 37393-1-1, on Poaceae , coll. F.F. Niu ; nine ap. viv. fems., Xinjiang , 11.VII.1977, No. 6892, on Salix , coll. Y.H. Han ( Zhang and Zhong 1985) ; two ap. viv. fems., Xinjiang , 11.VII.1977, No. 6644, on Salix , coll. Y.H. Han ( Zhang and Zhong 1985) ; two ap. viv. fems., Qinghai , 14.VI.1997, No. 11430, on Salix , coll. X.L. Chen ( Zhang et al. 1999) ; eighteen ap. viv. fems., Qinghai , 13.VI.1997, No. 11417, on Salix , coll. X.L. Chen ( Zhang et al. 1999).

Diagnosis.

Body dorsum is covered with wavy or irregular circular wrinkles; ABD TERG VIII with short conical supra-caudal process, blunt at apex (Fig. 1G, I ); siphunculus clavate, obliquely truncated at tip, without flange (Fig. 1H ) ( Gillette and Bragg 1916; Zhang and Zhong 1985; Zhang et al. 1999).

Comments.

The species migrates between Salix and Poaceae , Cyperaceae , or Juncaceae , and the supra-caudal process has some variations between the host plants. The population feeding on Salix has a broad, short, conical supra-caudal process (Fig. 1I ), while those on secondary host plants have a slightly larger supra-caudal process; sometimes the ABD TERG VIII bends backward to a triangular supra-caudal process (Fig. 2B, C ), so there can be some misidentifications to this species. Zhang et al. (1999) described Cavariella cessana (Fig. 2D-F ) based on apterae and alatae feeding on Salix . After checking many specimens of the two species in China, they were found to be the same species feeding on different host plants. Additionally, the molecular data supported that C. aquatica and C. cessana are the same species (Fig. 38 ). Therefore, Cavariella cessana Zhang, Chen, Zhong & Li, 1999 should be considered as a junior synonym of Cavariella aquatica (Gillette & Bragg, 1916).

Biology.

Primary host plant: Salix ; secondary host plant: Poaceae , Cyperaceae , or Juncaceae . The species feeds on upper sides of leaves and tender tips of the primary host plant (Fig. 32A, B ). As to the secondary host plant, the species feeds on a water-grass Catabrosa aquatica (L.) growing on seeped land and usually was found in the water along the margins of ditches in USA ( Gillette and Bragg 1916). In China, the species feeds on the upper surfaces of Hordeum vulgare var. coeleste L. (Fig. 32C ).

Distribution.

China (Qinghai, Tibet, Xinjiang), Afghanistan, Canada, Europe, India, Kazakhstan, Pakistan, USA.

Figures

Figure 1. Cavariella (Cavaraiellia) aquatica (Gillette & Bragg). Apterous viviparous female: A dorsal view of body B dorsal view of head C antenna D ultimate rostral segment E mesosternal furca F sculptures of abdominal tergites G abdominal tergites VI-VII H siphunculus I supra-caudal process on abdominal tergite VIII J cauda K anal plate. Alate viviparous female: L dorsal view of body M antenna. Scale bars: 0.10 mm.

Figure 2. Cavariella (Cavaraiellia) aquatica (Gillette & Bragg) feeding on Poaceae: A dorsal view of body B abdominal tergites VI-VIII C supra-caudal process on abdominal tergite VIII. Cavariella cessana Zhang, Chen, Zhong & Li, 1999, syn. nov. D dorsal view of body E abdominal tergites VI-VIII F siphunculus. Scale bars: 0.10 mm.

Figure 32. The ecological habitat photographs of Cavariella in the field A, B the apterae and nymphs of Cavariella aquatica (Gillette & Bragg) feeding on the leaves of Salix along main vein C the apterae and nymphs of Cavariella aquatica feeding on the leaves of Poaceae D the apterae and nymphs of Cavariella aegopodii (Scopoli) feeding on the leaves of Salix along main vein E the apterae and nymphs of Cavariella angelicae (Matsumura) feeding on the tender leaves of Salix F the apterae and nymphs of Cavariella araliae Takahashi feeding on tender tips of Aralia G the apterae and nymphs of Cavariella bhutanensis Chakrabarti & Das feeding on the leaves of Salix along main vein H the apterae of Cavariella gilgiana Zhang, Chen, Zhong & Li feeding on the leaves of Salix.

Figure 38. Neighbor-joining tree for Cavariella and Elatobium samples based on COI sequences.