Research Article |
Corresponding author: Xiao Hui Hou ( hxh19801122@163.com ) Academic editor: Art Borkent
© 2019 Chen Duan, Xiao Hong Jiang, Qiong Qiong Chang, Xiao Hui Hou.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Duan C, Jiang XH, Chang QQ, Hou XH (2019) First description of the immature stages of Dasyhelea alula and a redescription of adults from China (Diptera, Ceratopogonidae). ZooKeys 824: 135-145. https://doi.org/10.3897/zookeys.824.31722
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The fourth instar larva and pupa of Dasyhelea alula Yu, 2005 are described and illustrated using a Scanning Electron Microscope. The adult male and female of this species are redescribed. Immatures were collected from flooded soil near a pond in Xiaojiawan village, Guizhou province, China and reared in the laboratory. The studied material is deposited in the Insect Collection of Zunyi Medical University.
Adult, aquatic, biting midge, China, description, fourth instar larva, pupa
Biting midges of the genus Dasyhelea Kieffer, 1911 (Diptera: Ceratopogonidae) are common and widespread, and are found in all regions of the world in a wide variety of habitats (
The specimens were collected with the aid of a scoop from flooded soil in Xiaojiawan village, Guizhou province, China and carried to the laboratory in summer of 2018. They were placed in separate Petri dishes (larvae) and glass vials (pupae) with a small amount of water and reared in an environmental chamber (LZX-300L-III, Shanghai Xinlang Electronic Technology Ltd, Shanghai, China) maintaining 28 ± 2 °C temperature, RH 75 ± 2% and photoperiod of 12 h: 12 h (6W LED tube-light). The pupae were observed daily until adult emergence. The emergent adults and whole larvae and pupae were preserved in ethanol. The specimens were mounted in Canada balsam following
HL head length;
HW head width;
HR head ratio;
SGR ratio of subgenal and head width;
SGW subgenal width;
MDL mandible length;
MDW mandible width;
LAW width across the lateral arms of epipharynx;
DCW width across each of the paired dorsal comb sclerites of the epipharynx;
ROL respiratory organ length;
ROW respiratory organ width;
ROP/ROL respiratory organ pedicel length / respiratory organ length;
DAL dorsal apotome length;
DAW dorsal apotome width;
DAW/DAL dorsal apotome width / dorsal apotome length.
Dasyhelea (Pseudoculicoides) alula Yu, 2005: 259 (male and female, China)
2 males, 3 females, 3 larvae, 3 larval exuviae, 2 male pupal exuviae, 3 female pupal exuviae. Xiaojiawan village, Xinpu new district, Zunyi city, Guizhou province, China, 27°43'22.83"N; 107°04'27.62"E, 7.VII.2018, alt. 866 m, Chen Duan leg.
Fourth instar larva (Figs
Dasyhelea alula Yu. Larva (a–c), male pupa (d–e), female pupa (f–g). a head, dorsal view b epipharynx, dorsal view c hypopharynx, dorsal view d dorsal apotome (male) e segment IX (male) f dorsal apotome (female) g segment IX (female). Scale bars: 0.1 mm. Abbreviations: hypostoma (HY); hypopharynx (hpy); epipharynx (epy); genital lobe (GL); terminal process (TP).
Dasyhelea alula Yu, larva. a head capsule (palatum, frontal view) b detail of labrum c detail of scopae d detail of lacinial sclerite I e caudal segment f detail of caudal segment. Abbreviations: antenna (AN); galeolacinia (GL); hypostoma (HY); hooks (H); labrum (LB); lacinial sclerite I (LC1); lacinial sclerite II (LC2); maxilla (MX); maxillary palpus (MP); palatum (PL); sensilla coeloconica (Sco); sensilla campaniformia (Sca); scopae (Sc).
Pupa (Figs
Dasyhelea alula Yu. Male adult (a–c), female adult (d–e), male pupa(f–k). a genitalia b parameres c aedeagus d subgenital plate e spermatheca f clypeal/labral sensilla and ocular sensilla g dorsolateral cephalic sclerite sensilla h anterolateral and anteromedial sensilla i metathoracics sensilla, lateral and dorsal sensilla of first abdominal segment j dorsal and supraalar sensilla k dorsal, lateral and ventral sensilla of segment IV. Scale bars: 0.1 mm.
Female. Similar to male with usual sexual differences. Total length 1.64–1.75 (1.70, n = 2) mm. General coloration of exuviae pale brown, except dorsolateral cephalic sclerite brown. Dorsal apotome (Fig.
Male
Head. Eyes (Fig.
Dasyhelea alula Yu. Male adult (a–e), female adult (f–k). a frontal sclerites, anterior view b flagellomeres, anterior view c clypeus, anterior view d palpus, anterior view e genitalia, ventral view f flagellomeres, anterior view g frontal sclerites, anterior view h clypeus, anterior view i palpus, anterior view j wing k subgenital plate and spermatheca, ventral view. Scale bars: 0.1 mm.
Thorax. Scutum dark brown, scutellum yellow, with six stout setae. Legs brown; hind tibial comb with eight spines; foreleg TR 2.18, midleg TR 2.21, hind leg TR 2.33. Wing length 1.12 mm, width 0.33 mm, CR 0.40; wing membrane hyaline, densely covered with microtrichia, cubital fork at same level of distal portion of second radial cell.
Abdomen. Brown. Tergite IX nearly trapezoidal with prominent apicolateral processes. Posteromedial margin of sternite IX with elongate, slender projection, gonostylus slender (Figs
Female (Figs
Head. Eyes contiguous. Antennal flagellum (Fig.
Thorax. Hind tibial comb with seven spines; foreleg TR 2.00, midleg TR 2.14, hind leg TR 2.16. Wing length 0.82 mm, width 0.34 mm, CR 0.50 (Fig.
Abdomen. Similar to male. Subgenital plate (Figs
Dasyhelea alula belongs to the subgenus Pseudoculicoides and the johannseni group, of which are there 12 species in China: D. arciforceps Tokunaga, D. alula Yu, D. curtus Yu & Yan, D. communis Kieffer, D. ermeri Remm, D. excellentis Borkent, D. microsporea Hao & Yu, D. navai Xue & Yu, D. subcommunis Yu, D. turficola Kieffer, D. turanicola Remm, and D. tessicola Remm. Other than D. alula, the larvae and pupae of D. communis are the only described immatures of any species within this group. The larva of D. alula is similar to D. communis by virtue of the mandible with three same-sized teeth, but the dorsal comb of epipharynx has small and dense teeth. In addition, the larva of D. alula is also similar to that of D. mediomunda, the shared features as follows: head capsule is short, the medial portion of the hypostoma smooth, the lateral arms of the epipharynx stout and lacking teeth, but the larva of D. mediomunda differs by having inconspicuous scopae, the mandible with two teeth and the anterior portion of palatum with three pairs of campaniformia. The pupa of D. alula is similar to that of D. eloyi with scale-like spines on the respiratory organ, but the latter differs by having 16–18 apical and 5–6 lateral pores. The pupa of D. alula otherwise matches the generic features of Dasyhelea as described by
We are grateful to Pr Run Zhi Zhang for help in the laboratory platform, to Dr Kui Yan Zhang for technical assistance, and to Dr Art Borkent for critical reading of the manuscript. This research was financially supported by the grant from the National Natural Science Foundation of China (No. 81802040) and the Western Light Project.