Myrmeleon heppneri Miller and Stange, 1999

Lin, Yu-Hsiu, Liao, Jhih-Rong & Ko, Chiun-Cheng, 2021, Fig. 5 in Periclimenaeus karantina Park & De Grave 2021, sp. nov., Zoological Studies 60 (39), pp. 1-24 : 9-11

Myrmeleon heppneri Miller and Stange, 1999 ( Figs. 3D , 4D , 9 )

Description of 3rd instar larva: Size: Average body length 6.95 mm (6.17–7.77); head length 1.60 mm (1.42–1.82), head width 1.39 mm (1.29–1.47), mandible length 1.68 mm (1.52–1.80), ratio head width/length 0.87, ratio mandible length/head length 1.05.

General coloring: Pale ochre, slightly yellowish, with dark brown body markings.

Head: Sub-rectangular, longer than wide. Covered with short, black setae; ventral side with a setae-less area in the middle. Ocular tubercle sessile. Mandibles pale brown with apex reddish, as long as the head capsule, provided with 3 equidistant teeth with the apical tooth slightly stronger. Interdental mandibular setae: (4–7)(2–3)(2–3)(1–2). Clypeo-labrum with pointed setae. External margin of the mandible with a fringe of long setae, dorsal side of the mandible with a row of setae along the external margin, ventral side of the mandible without setae. Labial palpus 3-articulated, with fringe of black setae underneath, few extending over labial palpus. Dorsal side of the head capsule with dark markings on clypeo-labrum, a pair of dark spots on the anterior side, followed by a pair of pale brown spots, posterior side with a pair of greyish brown markings, lateral margins with greyish brown stripes. Lateral side of the head with a posterior dark spot. Ventral side of the head pale, with a pair of small dark spots on the anterior side and a pair of larger dark spots on the posterior side, occasionally fusing into a stripe.

Thorax: Pronotum with two pairs of dark brown stripes, covered with short setae. Body setae black.

Legs: Pale brown, unspotted.

Abdomen: Setae black, with pale brown setae on the ventral side. VIII abdominal sternite with a pair of dark brown markings, odontoid processes reduced, posterior margin with black stout setae interspersed with pale brown setae. IX abdominal sternite with a pair of small dark brown spots, irregularly dispersed with at least three rows of digging setae. Rastra sessile, each bearing 4 stout, peg-like digging setae equal in size.

Materials examined: Taiwan. Taoyuan City. Zhuwei Beach, Dayuan District / 27. X. 2019 / Y. H. Lin leg., 9 L3; same locality / 08. XI. 2019 / Y. H. Lin leg., 2 L3, 1 L3 laboratory reared to adult; same locality / 14. VI. 2020 / Y. H. Lin leg., 2 L3, 1 L3 laboratory reared to adult.

Bio-ecology: M. heppneri is one of the rarest species of Myrmeleon of Taiwan, only recorded from very few beaches. The larvae build pitfall on open sand dunes, usually under vegetation on downwind slopes, with similar habitat preference to M. persimilis . In Zhuwei Beach of Taoyuan City, M. persimilis are absent while a stable population of M. heppneri were found; therefore, interspecific competition among these species requires further exploration.

Distribution: Endemic to Taiwan. Only recorded in Tamsui Beach and Zhuwei Beach in the north-west coast of Taiwan.

Remarks: The larvae of M. heppneri resembles M. persimilis in the arrangement of digging setae on IX abdominal sternite and in the absence of setae on the ventral side of the mandibles, the two can be distinguished by the markings on head capsule.

Variations exist on ventral head markings of M. heppneri , because the anterior and posterior spots might fuse together forming a stripe, or they might be barely visible. These variations may cause misidentification with the larvae of M. punctinervis or M. bimaculatus if depending solely on ventral head markings.

Figures

Fig. 3. Head of 3rd instar larvae of Myrmeleontini of Taiwan, ventral view; A, Baliga asakurae; B, Myrmeleon alticolus; C, Myrmeleon bimaculatus; D, Myrmeleon heppneri; E, Myrmeleon littoralis; F, Myrmeleon persimilis; G, Myrmeleon punctinervis; H, Myrmeleon taiwanensis; I, Myrmeleon wangi. Scale bar = 1 mm.

Fig. 4. IX abdominal sternite of 3rd instar larvae of Myrmeleontini of Taiwan, ventral view; A, Baliga asakurae; B, Myrmeleon alticolus; C, Myrmeleon bimaculatus; D, Myrmeleon heppneri; E, Myrmeleon littoralis; F, Myrmeleon persimilis; G, Myrmeleon punctinervis; H, Myrmeleon taiwanensis; I, Myrmeleon wangi. Scale bar = 1 mm.

Fig. 9. Myrmeleon heppneri Miller and Stange, 1999, 3rd instar larva. A, dorsal view; B, ventral view; C, lateral view.