Myrmecaelurus trigrammus (Pallas, 1771)

Badano, Davide & Pantaleoni, Roberto Antonio, 2014, The larvae of European Myrmeleontidae (Neuroptera), Zootaxa 3762 (1), pp. 1-71 : 41-43

Myrmecaelurus trigrammus (Pallas, 1771)

( Figs. 1D , 2B , 21 )

The first reliable larval description of this species was redacted by Redtenbacher (1883, 1884), because the previous accounts were not diagnostic and referable to other species ( Brauer 1867; Hagen 1873). Curiously, in the past M. trigrammus was repeatedly described as the larva of other species of antlions: Redtenbacher (1883, 1884) erroneously assigned the larvae of this species also to Creagris plumbeus , Macronemurus appendiculatus and Macronemurus bilineatus ; Doflein (1921), following the previous author, attributed them to Macronemurus appendiculatus and Megistopus flavicornis . Later Hölzel (1974) described the larva of this species mistaking it with Myrmeleon gerlindae . Recently the larva of this species was exhaustively treated ( Willmann 1977; Popov 1984; Gepp 2010; Krivokhatsky 2011; Devetak et al. 2013).

Examined specimens. Italy. Calabria, Strogoli ( Crotone ), VIII.2010 (C. Labriola), 1 L3. Sicily, Gurne dell’Alcantara (Messina), VII.2010 (A. Corso), 3 L3 . Greece. Rhodos, Kamiros , VII.2009 (D. Badano), 1 L3 laboratory-reared to adult . Romania. Dobruja, Badabag , VIII.2010 (C. Manci), 2 L3 . Turkey. Cappadocia, Göreme , V.2010 (A. Letardi), 3 L3 .

Description of 3 rd instar larva. Size (based on 9 specimens): BL 9.83 mm; HL 2.42 mm (2.29–2.59), HW 2.05 mm (1.97–2.18), ML 2.14 mm (1.78–2.32), HW/HL 0.85, ML/HL 0.88. General colouring ochre with dark brown markings, ventral side pale with dark spots; head capsule with dorsal and lateral sides dark brown while the area surrounding the ocelli is paler, ventral side of the head with a dark pattern ( Fig. 21c ); mandibles pale brown with a darker apex; setae of the body black. Head slightly longer than wide; mandibles shorter than the head capsule and comparatively robust; distance between the base of the mandible and basal tooth larger than that between the basal and the apical teeth, median tooth in contact with the apical tooth ( Fig. 21a ); interdental mandibular setae (+7)(2)(0)(0); external margin of the mandible with a fringe of long setae ( Fig. 21b ). Mesothoracic spiracles brown. Abdominal spiracles brown; VIII sternite with digging setae on the posterior margin; IX sternite with large digging setae, posterior margin with two prominent rastra bearing 4 subequal digging setae ( Fig. 2B , 21d ).

Bio-ecology. M. trigrammus is associated with steppe-like biotopes such as dry meadows and grasslands. The larvae are pit-builders but they also retain an ambush hunt behaviour that they display according to the situation. The pits are often built in open conditions, often in proximity tuft of grass, but they have also been observed near shelters such as stones, logs or rock escarpments.

Remarks. M. trigrammus is the only European member of the genus thus allowing to identify its larvae with ease. A similar species M. major McLachlan 1875 is reported from the uncertain border between Europe and Asia, however the larval stages of the latter remain unknown as well the other members of genus. The larvae of Nohoveus zigan H. Aspöck, U. Aspöck et Hölzel, 1980 and Aspoeckiana uralensis Hölzel, 1969 notably differ in the presence of setae between the median and apical mandibular teeth and in the characteristics of the IX sternite ( Krivokhatsky 2011).

Figures

FIGURE 1. Taxonomic characters of larvae of Myrmeleontidae. A, Euroleon nostras dorsal and ventral views; B, head of Myrmeleon inconspicuus; C, head of Macronemurus appendiculatus; D, IX and VIII sternite of Myrmecaelurus trigrammus; E, IX and VIII sternite of Creoleon lugdunensis.

FIGURE 2. IX and VIII abdominal sternite of 3rd instar larvae of Palparini, Myrmecaelurini, Nesoleontini and Acanthaclisini. A, Palpares libelluloides; B, Myrmecaelurus trigrammus; C, Cueta beieri; D, Cueta lineosa; E, Acanthaclisis occitanica; F, Synclisis baetica. Scale bar: 1 mm.

FIGURE 21. Myrmecaelurus trigrammus (Pallas, 1771), 3rd instar larva (Italy: Calabria, Strogoli). Dorsal (above), ventral (middle) and lateral (below) view; a–d: diagnostic characters, see species description.