Agrilus adelphinus Kerremans, 1895

Huang, Xuyan, Gan, Yujie, Wang, Lei, Xu, Yanying, Wei, Zhonghua & Shi, Aimin, 2023, The larval, pupal and mitogenomic characteristics of Agrilus adelphinus Kerremans, 1895 (Coleoptera, Buprestidae) from China, ZooKeys 1174, pp. 15-33 : 15

Agrilus adelphinus Kerremans, 1895

Agrilus adelphinus Kerremans, 1895: 222.

Agrilus egorovi Alexeev, 1989: 480.

Agrilus nigrocoerulans Obenberger, 1924: 39.

Agrilus nonfiedanus Obenberger, 1923: 65.

Agrilus nonfriedi Obenberger, 1914: 49.

Agrilus panhensis Baudon, 1968: 117.

Examined specimens.

Adults: 13♂14♀, China: Hebei: Qinhuangdao, 40.3332°N, 119.4090°E, 16-V-2022. Larvae: 13 exs., the same data as adult. Pupae: 5 exs., the same data as adult.

Distribution.

China: Hebei, Shanxi, Shandong, Shaanxi, Anhui, Hubei, Guangxi, Sichuan, Yunnan, Xizang; Russia (Far East), Korean Peninsula, Japan.

Note.

The adults of A. adelphinus appeared in May to August.

Description of larva

(Fig. 2 ). Body length 9-17 mm; widest in prothorax, 1-1.8 mm. Body shape (Fig. 2A, B ) of agriloid type; expanded thorax distinctly wider than abdominal segments, except for abdominal segment I wider than metathorax and terminal abdominal segments VIII-IX at least of same width as prothorax. Body light yellow or white; surface smooth, with insignificant long setae.

Head prognathous, mostly retracted into prothorax. Labrum (Fig. 2F ) strongly transverse, gradually becoming narrower anteriorly, approximately 2 × wider than long; anterior margin straight, with dense mircosetae; lateral margins distinctly arched; surface weakly convex, smooth, with four short setae at base. Anteclypeus membranose, oblong, strongly transverse, approximately 3 × wider than long; surface smooth.

Epistome (Fig. 2F ) weakly sclerotized, brown, semitranslucent, strongly transverse, approximately 5.2 × wider than long; anterior margin emarginate in middle; anterior angles rounded; surface smooth, distinctly convex, with four sensilla in two groups situated in shallow, round depressions in middle, as known in other buprestid larvae. Mandibles triangular, black, strongly sclerotized; basolateral outer margin with a long seta; internal margin with based penicillum bearing dense, short setae.

Maxillae (Fig. 2F ): cardo strongly transverse, well sclerotized in lateral parts, weakly sclerotized and semitranslucent in middle part; posterior margin distinctly wider than anterior; lateral parts each with two long setae. Stipes subquadrate, slightly sclerotized; apical margin with setae as long as basal palpomere, and with a long seta on internal parts. Mala elongate, narrowed apically; anterior margin with setae slightly longer than those on stipes.

Antennae situated in deep incision, two-segmented, subcylindrical; antennomere I slightly expanded apically, approximately 1.2 × as long as antennomere II and distinctly thicker than antennomere II; surface glabrous except anterior margin with dense microsetae. Second antennomere with a long trichosensilla, approximately 1.6 × as long as antennomere II, and bearing some short trichosensilla extending beyond sensory appendage and two palmate sensilla on the apex of second antennomere ( Volkovitsh and Hawkeswood 1990). Prementum (Fig. 2G ) subquadrate, 1.2 × as long as wide; anterior margin weakly arcuate; anterior angles rounded; lateral margins subparallel, anterior parts weakly expanded; anterior surface with dense microsetae, posterior border of microsetal area M-shaped; posterior surface glabrous.

Prothorax (Fig. 2C, D ) distinctly longer and wider than mesothorax and metathorax, widest in the middle, 1.5 × as wide as meso- and metathorax; lateral margins arcuate; dorsal and ventral plates each with a longitudinal pronotal and prosternal grooves; anterior part of pronotal groove slightly wider than posterior, posterior part not bifurcated. Mesothorax as wide as metathorax. Thoracic spiracles on lateral parts of mesothorax. Thorax without legs.

Lateral parts of abdominal segments with sparse, long hairs. Abdominal segments I-IX subquadrate, slightly wider in middle. Lateral parts of segments I-VIII each with a pair of spiracles anteriorly; segments IX and X without spiracles. Posterior part of abdominal segment X rounded, lateral parts with long setae denser than in middle, with a pair of sclerotized terminal processes. Terminal processes long, subcylindrical, gradually tapering from base to apex; each process with two subdivisions in internal margin (Fig. 2E ).

Description of pupa

(Fig. 3 ). Body length 10-14 mm, width 3-3.8 mm. Body (Fig. 3A, B, D, E ) exarate, white; eyes and mouthparts darker. Pygidium slightly brown apically; body surface smooth, without setae.

Head hypognathous; mouthparts and frons invisible in dorsal view; most eyes and vertex visible in dorsal view; surface with dense, small, black spots. Mandibles strongly sclerotized. Antennae placed along lateral sides of prosternum, directed backwards, reaching basal margin of prosternum.

Pronotum (Fig. 3C, F ) shaped nearly like an inverted trapezoid, widest in anterior 1/3; anterior margin distinctly wider than posterior; anterior angles produced; anterior pronotal lobe arcuate and not reaching level of anterior angles; lateral margins weakly arcuate; posterior angles nearly rectangular; Posterior margin with two strongly convex tubercles in middle; disk smooth. Prosternal process narrowed; angles of prosternal process obtuse. Prehumerus carinal, posterior end joining posterior pronotal angle. Marginal and submarginal carinae converging and fused posteriorly, interspace wide, narrowest point at posterior 1/3 of pronotum. Mesonotum strongly impressed, except base of elytra. Elytra distinctly developed; elytral apex extending to posterior margin of abdominal ventrite III. Most part of metathoracic wings covered by elytra, extending to anterior margin of abdominal ventrite II. Metasternal projection impressed. Metanotum with a deep, longitudinal groove, nearly V-shaped, anterior part distinctly wider than posterior. Legs semitransparent.

Abdomen widest at tergites IV (ventrite I + II). Tergites I-VII with dense, large punctures bearing very short setae. Tergites I-VI subequal in length; pygidium distinctly longer than other tergites, posterior margin arcuate, with setae longer than those on tergites I-VI; anterior margin of tergites III-VI and posterior margin of tergite I black. Ventrite I + II distinctly longer than ventrites III-V; posterior margins of ventrites I + II to IV light brown. Surface of ventrites I- IV smooth, with indistinct short setae; posterior of ventrite V with long setae; posterior margin of sternite V arcuate. Spiracles located on anterio-lateral margin of tergites I-VII, paired, and ovate; spiracles on tergite I distinctly larger than those on tergites II- VII. Female: posterior margin of sternite V deeply, arcuately sinuate.

Figures

Figure 2. Larva of Agrilus adelphinus A, C dorsal view B, D ventral view E terminal processes in dorsal view F, G mouthparts in dorsal view and ventral view, respectively. Scale bars: 1 mm (A-E).

Figure 3. Pupa of Agrilus adelphinus A, D dorsal view B, E ventral view C, F head and pronotum in dorsal view. Scale bars: 1 mm.