Chaetolonchaea alliumi Zhang et Xue

Zhang, Ting-Ting, Liu, Fang, Macgowan, Iain & Xue, Ming, 2017, A new species of Chaetolonchaea Czerny (Diptera: Lonchaeidae) from China, a larval pest on chives, Zootaxa 4250 (4), pp. 358-366 : 361-366

Chaetolonchaea alliumi Zhang et Xue

( Figs. 1–16 , 21–28 )

Diagnosis. Body subshining black. Hairs on compound eyes very short and sparse. Frons covered by sparse short setulae. Gena 0.2x as high as head. Black setulae of vein C extend to the end of vein R4+5; distance between apices of vein Sc and vein R1 is shorter than greatest width of costal cell. There are 1–3 lateral setulae between basal and apical scutellar setae. Cerci are wider than high in posterior view. The basal margin of cerci is nearly straight while the apical margin with a central V-shaped incision; surstylus with 3 prensisetae, the anterior very small, the posterior rather large and strongly curved inward.

Description. Adult. Male ( Figs. 1 , 25 ). Body length 4.0–5.0 mm; wing length 4.2–4.9 mm.

Head ( Fig. 3 ); subshining black. Eyes reddish brown, sparsely short yellow haired; the longest hairs a little shorter than width of parafacial. Ocellar triangle shining black with strong ocellar setae. Frons gradually narrowed toward lunule, pale grey pollinose with approximately 12 frontal and interfrontal setulae, about 0.5x as long as orbital seta. Width of frons just above lunule 0.67x as wide as one eye in frontal view. Orbital plate pale grey pruinose; orbital seta strong, no setulae present. Lunule and face black, pale grey pruinose without setulae. Parafacial densely silvery pollinose. Gena broad, about 0.2x as high as head in lateral view, with 3–4 rows of setulae on lower part. Antennae entirely brownish black with brown pubescence; pedicel with a strong dorsal seta, first flagellomere 1.6x as long as deep; arista pubescent, 3.0x as long as 1st flagellomere. Proboscis brown. Palpus black, covered with black setulae.

Thorax ( Fig. 2 ); scutum subshining black, covered with short setulae. Prescutellar area with 2 setulae. Anepisternum with 5 strong seta along posterior margin, covered in setulae except anteriorly. Katepisternum with 2 strong setae near dorsal margin, anterior weaker than posterior, remainder of sclerite with a few scattered setulae, bare posterior to the strong setae. Anepimeron and katepimeron bare. Scutellum subshining black, on margin with one setula anterior to basal seta and 1–3 setae between basal and apical setae, bare between apical setae. Legs entirely black. Setae on posteroventral suface of front and mid femora (only apical part of mid femur) stronger than those on other parts of the legs; hind femur with 2 strong sub-apical anteroventral setae; mid tibia with strong apical ventral seta. Wing ( Fig. 7 ) hyaline, tinged in pale yellow, 2.4x as long as wide; veins brownish yellow; vein C with 1 strong seta before crossvein h; black setulae of vein C extending to end of vein R4+5; distance between apices of vein Sc and vein R1 0.83x as long as greatest width of costal cell. Calypteres whitish yellow with yellow margins and fringes. Halter black with stem yellowish brown.

Abdomen; tergites subshining black, slightly longer and narrower than thorax, cone-shape, tapering toward apex. Tergite 5 longer than combined length of tergite 3 and 4; with a small mid-apical process and 7 short denticles along each postero-lateral margin.

Male terminalia ( Figs. 11–14 ): Epandrium wider than high in lateral view, about semi-circular in shape. Cerci wider than high in posterior view, basal margin extended laterally, nearly straight but with tiny median cuspides in posteroventral view, apical margin divided into 2 rounded lobes with a V-shaped incision between them. Surstylus extending anteriorly from shell of epandrium separated into two parts; anterior part as a bar with round, expanded and setulose tip, the posterior part triangular with 3 black acute prensisetae. The anterior prensiseta very small, the posterior one large and strongly curved inward. Phallus little developed, two segmented, basiphallus short and rather membraneous; distiphallus ampuliform, slender, narrower apically, apical rod slightly curved ventrally.

Female ( Figs. 4–6 , 26 ): Most characters similar to male, but eyes widely separated on frons; frons nearly parallel-sided and about 2.0x as wide as width of one eye in frontal view. Parafacial shining black with narrow silvery border along eyes. Hairs on eyes sparse and shorter than diameter of ocellus. Female terminalia ( Figs. 15, 16 ): Apical segment of aculeus bullet-shaped with preapical dorsal setae about 0.5x length of sub-basal dorsal setae; slightly shorter than subapical ventral setae.

Egg ( Fig. 21 ). Length 1.7–1.8 mm; width 0.4 mm. Spindle shape in outline. Ivory white in color with short longitudinal sculptures entire surface. A pair of longitudinal grooves from micropyle to middle of the egg.

Larva ( Figs. 22–24 , 27, 28 ). Slender, peg-shaped, ivory white in color. Anterior spiracle with 9–12 fingerlike projections arranged fan-wise. Posterior spiracles each on a raised tumplike tubercle, round, smooth around, without any lobe or ridge. Each posterior spiracle with 3 oval radially arranged slits, at right angles to one another, without spiracular hairs.

Head skeleton; (terminology follows Rotheray, 2016) The head skeleton shows the typical attributes of a phytophage; basal sclerite with dorsal cornu long and thin, ventral cornu 2.5x as wide and slightly longer, with a well-developed dorsal apodeme, dorsal bridge well developed, dental sclerite relatively large and stout with long pointed mandibles, dental apodeme well developed.

Puparium ( Figs. 8–10 ). Length 4.6–6.0 mm; width 1.7–2.3 mm. Spindle shape in outline. Reddish brown in color. Posterior spiracles round and distinct, anterior spiracles projecting.

Specimens examined. Holotype: ♂, CHINA, Shandong, Taian, Ningjiajiezhuang , 2013. IX. 5, Ming Xue ( SDAU) . Paratype: 1♂, CHINA, Shandong, Taian, Ningjiajiezhuang, 2014. IX. 12, Ming Xue ( SDAU) ; 1♂ 1♀, CHINA, Shandong, Taian, Ningjiajiezhuang, 2016. IX. 1 (bulb of chives ( Allium tuberosum )/larvae [2015. X.23]/ puparia [2015. XI.2]), Fang Liu ( SDAU) ; 1♂ 1♀, CHINA, Shandong, Jinan, Changqing, 2015. IX. 15, Fang Liu ( SDAU) ; 1♂ 1♀, CHINA, Shandong, Weifang, Changle county, Tangwu town , 2016. IX. 8, Fang Liu ( SDAU) ; 1♂ 1♀, CHINA, Shandong, Taian, Ningjiajiezhuang, 2016. IX. 1 (bulb of chives ( Allium tuberosum )/larvae [2015. X.23]/puparia [2015. XI.2]), Fang Liu ( IZCAS) .

Distribution. China (Shandong).

Etymology. The species is named after its host chives ( Allium tuberosum Rottl. ex Spreng. )

Remarks. The new species is most similar to Chaetolonchaea pallipennis (Zetterstedt, 1855) ( Figs. 17–20 ) from Europe in that the eye hairs short and katepisternum has 2 strong setae, but it can be separated from the latter in the following characters: frons with sparse short setulae; black setulae on vein C extend to the end of vein R4+5; distance between apices of vein Sc and vein R1 shorter than greatest width of costal cell; male terminalia: in posterior view cerci with basal margin nearly straight and apically forming two rounded lobes with a V-shaped incision between; surstylus with 3 prensisetae of which the anterior one is very small and the posterior one rather large and strongly curved inward.

In Chaetolonchaea pallipennis , hairs on frons are much longer and denser; the black setulae of vein C extend to a point about 1/3 of distance between apices of vein R2+3 and vein R4+5; distance between apices of vein Sc and vein R1 longer than greatest width of costal cell; cerci more rounded in posterior view; male terminalia ( Figs. 17– 20 ): in posterior view cerci coming to a blunt point at apex with small lateral projections, surstylus with prensisetae but the anterior although smaller not markedly smaller than the others.

Currently the new species is only found on Chinese chives ( Allium tuberosum Rottl. ex Spreng. ), causing serious losses in some parts of China. The larva drills the underground root and bulb of the chives ( Figs. 27, 28 ) resulted in yellowing, poor growth of the plant, even whole death. Detail information of the biology about this species will be reported in other papers.

Figures

FIGURES 1 – 6. Adult of Chaetolonchaea alliumi Zhang et Xue. 1. Male body, lateral view; 2. Male thorax, dorsal view; 3. Male head, frontal view; 4. Female body, lateral view; 5. Female thorax, dorsal view; 6. Female head, frontal view.

FIGURES 7 – 10. Wing and puparium of Chaetolonchaea alliumi Zhang et Xue. 7. Wing; 8. Puparium, ventral view; 9. Piparium, dorsal view; 10. Puparium, posterior view.

FIGURES 11 – 16. Chaetolonchaea alliumi Zhang et Xue. 11. Male genitalia, lateral view; 12. Ejaculatory apodeme, lateral view; 13. Male genitalia, ventral view; 14. Male genitalia, posteroventral view; 15. Ovipositor, lateral view; 16. Ovipositor, dorsal view.

FIGURES 21 – 24. Egg and larva of Chaetolonchaea alliumi Zhang et Xue. 21. Egg; 22. Mouthparts, lateral view; 23. Posterior end, posterior view; 24. Posterior end, lateral view.

FIGURES 25 – 28. Chaetolonchaea alliumi Zhang et Xue on the host. 25. Male; 26. Female; 27 – 28. Decomposed bulb of chives damaged by the larvae of C. alliumi.

FIGURES 17 – 20. Chaetolonchaea pallipennis (Zetterstedt). 17. Male epandrium and associated structures, ventral view; 18. Male epandrium and associated structures, posterior view; 19. Phallus, posterior view; 20. Phallus, lateral view.