Hoplitis (Hoplitis) dagestanica Fateryga, Mueller & Proshchalykin, 2023

Fateryga, Alexander V., Mueller, Andreas & Proshchalykin, Maxim Yu., 2023, Two new Hoplitis species of the subgenus Hoplitis Klug, 1807 (Hymenoptera, Megachilidae) and the nesting biology of H. astragali sp. nov. in Dagestan, Journal of Hymenoptera Research 96, pp. 641-656 : 641

Hoplitis (Hoplitis) dagestanica Fateryga, Mueller & Proshchalykin sp. nov.

Fig. 2A-H

Type material.

Holotype. Russia. Dagestan, Levashi district: Tsudakhar, 42°19'40"N, 47°09'48"E, 11.6.2019, ♂ (leg. A. Fateryga). Deposited in ZISP.

Paratypes. Russia. Dagestan, Levashi district: Tsudakhar, 42°19'40"N, 47°09'48"E, 1.6.2019, 2 ♂ (leg. A. Fateryga), 3 ♂ (leg. M. Proshchalykin, V. Loktionov); ibid., 10.6.2019, 2 ♂ (leg. A. Fateryga); ibid., 28-29.5.2022, 1 ♀, 1 ♂ (leg. A. Fateryga), 2 ♀, 13 ♂ (leg. M. Proshchalykin); Dagestan, Rutul district: near Kufa village, 6 km NW Rutul, 41.565178°N, 47.362029°E, 1500 m, 1.7.2018, 1 ♂ (leg. M. Proshchalykin, V. Loktionov, M. Mokrousov). Deposited in ZISP, FSCV, ETHZ, and CAFK.

Diagnosis.

Among the western Palaearctic Hoplitis species of the subgenus Hoplitis s. str., the female of H. dagestanica (Fig. 2A ) is unequivocally characterised by the following combination of characters: i) sternum 6 lateroapically with distinct submarginal carina and medioapically not elongated into distinct and well delimited tooth of narrowly triangular to linear shape; ii) proboscis not reaching till trochanter of hind leg in repose and second segment of labial palpus distinctly shorter than maximal length of mesosoma measured in lateral view (Fig. 2A ); iii) clypeus and galea of proboscis normally haired, without apically curved or wavy pollen-collecting bristles; iv) lateral lobes of pronotum not inflated; v) apex of inner tibial spur of hind leg strongly curved at an angle of 60 to 80 degrees (Fig. 2G ); vi) clypeus medially without uninterrupted sharp and narrow longitudinal carina; vii) disc of tergum 5 covered with rather dense and appressed cream-coloured to yellowish-white pilosity (Fig. 2C ); viii) when seen from behind, longest erect hairs on median half of tergum 1 only about 1/7 to 1/8 as long as maximal length of lateral hair tuft (Fig. 2E ); ix) punctation of lateroapical part of scutum with interspaces reaching the diameter of one puncture; x) metasomal scopa yellowish (Fig. 2A ); xi) anterior side of antennal articles (5)6-11 partly dark reddish-brown. The male of H. dagestanica (Fig. 2B ) is easily diagnosed by the following combination of characters: i) apical margin of tergum 7 medially rounded (Fig. 2H ); ii) second segment of labial palpus shorter than compound eye (Fig. 2B ); iii) last article of antenna almost twice as long as basally wide and tapering towards apex with ventral margin slightly concave (Fig. 2D, F ); iv) posterior side of antenna with roundish bump near distal end of articles (4)5-6 and small pointed tubercle near distal end of articles 7-11(12) (Fig. 2F ); iv) ventral margin of antennal articles (4)5-10(11) distally slightly widened (Fig. 2D ); v) antennal article 3 1.4-1.5 × as long as apically wide and longer than article 4 (Fig. 2D ); vi) lateral lobes of bilobed membranous appendage at apical margin of sternum 6 densely haired, distinctly wider than long, laterally elongated into a distinct and more or less acute tip and separated from each other by only a rather shallow median emargination (Fig. 2H ); vii) marginal zone of sterna 4-5 reddish and very densely punctured with interspaces much narrower than the diameter of one puncture (Fig. 2H ).

Assignment to species group.

Due to the presence of a submarginal carina on female sternum 6 and the apically rounded male tergum 7, H. dagestanica is clearly a member of the H. adunca species group.

Description.

Due to the uniform morphology of the numerous species of Hoplitis (Hoplitis) , the following description is restricted to characters, which are relevant for the recognition of the new species.

Female. Body length 7-8 mm. Head: Head about 0.95 × as long as wide. Distance between lateral ocellus and preoccipital margin about 1.75 × as long as ocellar diameter. Second segment of labial palpus about 1.35 × as long as first segment and about 0.75 × as long as compound eye. Proboscis reaching coxa of fore leg when folded. Mandible three-toothed, its preapical zone weakly reddish. Clypeus densely punctured with interspaces rarely surpassing the diameter of half a puncture and without distinct polished midline. Antennal article 3 almost 2 × as long as apically wide and about 2 × as long as article 4. Anterior side of antennal articles (5)6-11 partly dark reddish-brown. Mesosoma: Tegula yellowish-brown except for black anterior third and black inner margin. Scutum and scutellum densely punctured with interspaces rarely surpassing the diameter of one and a half punctures except lateroapically on scutum and medially on scutum and scutellum, where interspaces may reach the diameter of one puncture. Basal area of propodeum shagreened throughout. Posterior surface of propodeum shagreened with scattered punctures. Propodeal pit polished. Tibial spur of fore leg elongated into tip, which is slightly longer than basally wide and angularly stepped from more basal part of spur. Tibial spurs of hind leg yellowish; inner spur slightly tapering towards apex, which is strongly curved at an angle of 60 to 80 degrees (Fig. 2G ); outer spur slightly shorter than inner spur, its apex curved at an angle of about 45 degrees. Metasoma: Punctation of tergal discs moderately dense with interspaces reaching the diameter of two to three punctures on discs 1-3 (Fig. 2E ). Marginal zone of terga 1-5 covered with uninterrupted band of cream-coloured to yellowish-white hairs (Fig. 2A ), which may be interrupted on tergum 1 in worn specimens (Fig. 2E ). Tergal discs 1-4 with short erect pilosity of yellowish hairs, which are shorter than antennal article 2. When seen from behind, longest erect hairs on median half of tergum 1 only about 1/7 to 1/8 as long as maximal length of lateral hair tuft (Fig. 2E ). Disc of terga 5-6 covered with rather dense and appressed cream-coloured to yellowish-white pilosity. Sternum 6 lateroapically with distinct submarginal carina and medioapically without well delimited tooth (Fig. 2C ). Scopa yellowish.

Male. Body length 7.5-9.5 mm. Head: Head about 0.85 × as long as wide. Distance between lateral ocellus and preoccipital margin about 1.75 × as long as ocellar diameter. Second segment of labial palpus about 1.35 × as long as first segment and 0.75 × as long as compound eye. Proboscis reaching coxa of fore leg when folded. Mandible two-toothed and predominantly black, sometimes with dark reddish-brown preapical zone. Clypeus rather strongly convex in profile, its punctation very fine and dense without polished interspaces. Apical margin of clypeus medially straight and crenulate. Antennal article 1 about 2 × as long as maximally wide (Fig. 2D ). Antennal article 3 1.4-1.5 × as long as apically wide and almost 1.5 × as long as article 4 (Fig. 2D ). Posterior side of antenna with roundish bump near distal end of articles (4)5-6 and small pointed tubercle near distal end of articles 7-11(12) (Fig. 2F ). Ventral margin of antennal articles (4)5-10(11) distally slightly widened (Fig. 2D ). Last article of antenna almost twice as long as basally wide and tapering towards apex with ventral margin slightly concave (Fig. 2D ). Antenna predominantly yellowish-red; black to dark brown are articles 1, 2, base of 3, apex of 13, and sometimes dorsal side of articles 3-7 (Fig. 2F ). Mesosoma: Tegula predominantly yellowish-red. Scutum and scutellum densely punctured with interspaces hardly surpassing the diameter of one puncture. Basal area of propodeum shagreened throughout. Posterior surface of propodeum shagreened with scattered punctures. Propodeal pit polished. Tibial spur of fore leg elongated into tip, which is slightly longer than basally wide and angularly stepped from more basal part of spur. Tibial spur of hind legs yellowish, tapering towards apex and apically curved. Metasoma: Punctation of tergal discs moderately dense with interspaces reaching the diameter of three to four punctures on discs 1-4. Marginal zone of terga 1-5 covered with uninterrupted band of yellowish-white hairs (Fig. 2B ). Tergum 6 laterally toothed, its marginal zone reddish, ciliated with yellowish hairs, apically crenulate and medially usually slightly emarginate. Apical margin of tergum 7 medially rounded (Fig. 2H ). Marginal zone of sterna 2-5 reddish and very densely punctured with interspaces much narrower than the diameter of one puncture. Apical margin of sterna 1-4 almost straight and of 5 weakly rounded and medially shallowly emarginate. Marginal zone of sterna 2-4 with loose whitish hair band. Sterna 2-5 with preapical transverse swelling, which is sparsely punctured and medioapically emarginate on sterna 3-5. Sternum 6 basally with pair of membranous flaps (Fig. 2H ). Lobes of bilobed membranous appendage at apical margin of sternum 6 densely haired, distinctly wider than long, laterally elongated into a distinct and more or less acute tip and separated from each other by only a rather shallow median emargination (Fig. 2H ). Gonoforceps very narrow, slightly bent inwards and downwards in its apical third and apically with dense and short tuft of white hairs. Outer margin of penis valve ciliated with white bristles, of which the longest are slightly longer than the maximal valve width.

Distribution.

Mountain Dagestan in Russia (from 1120 to 1450 m a.s.l.).

Etymology.

The species epithet refers to the occurrence of the species in Dagestan.

Nesting biology

Six nests of Hoplitis astragali were studied 6 km northwest of Chirkey at a clay cliff along a dry riverbed (Fig. 3A ). All six nests were burrows in the ground. Two nests were located on strongly inclined surface (Fig. 4A ), while four nests were located on almost horizontal surface at the entrance of old burrows of Xylocopa olivieri Lepeletier, 1841 ( Hymenoptera : Apidae ) (Fig. 4B ). Thus, the main shaft of the former two nests was sub-horizontal (Fig. 4C ), while it was sub-vertical in the latter four nests (Fig. 4E, F ). The excavation process was not observed, but it was evident from the following observation that the burrows were self-excavated by the females: two closing plugs were observed on 31 May (Fig. 4D ) at the same old X. olivieri nest entrance, where there was just one burrow on 27 May (Fig. 4B ). Thus, the second burrow was excavated by the female bee, since there was no pre-existing hole available to her. It is noteworthy that the nest entrances were not always circular but sometimes of irregular shape (Fig. 4B ).

The nests were composed of one to three brood cells, an empty vestibule, and the closing plug. Of the six nests studied, two had one cell, three were two-celled, and one was three-celled (median two cells per nest). The lengths of the nest burrows were 16-32 mm (median 26 mm). The cells in two- and three-celled nests were linearly arranged in a straight burrow (n = 3, Fig. 4F ) or lay in an angled burrow with the longitudinal axis of the brood cells diverging at nearly right angles (n = 1, Fig. 4E ). When measured on the inside, the cells were 6.5-9.5 mm long (median 8.0 mm) and maximally 5.5-7 mm wide (median 6.0 mm). The inner surface of the cells was smooth, dull and not covered with any substance other than mud. Although the cell construction process was not observed, the presence of an about 0.4 mm thin and more or less distinct inner cell wall (Fig. 4C, F ) suggests that the female covered the inner surface of the cell with an extra layer of mud. As this extra layer was of the same colour as the surrounding substrate, the material for its construction was probably taken from inside the nest. The material used for the construction of the cell plug was apparently also taken from inside the nest as suggested by the irregular shape of the vestibule, indicating that soil material had been harvested from its walls (Fig. 4C, E, F ). In contrast, the closing plug was made from soil taken from outside the nest as evidenced by the plug colour, which usually differed from the surrounding substrate (Fig. 4D ). One female was observed to harvest dry clay from the cliff surface at a distance of about 0.5 m from the nest, mixed this material with regurgitated liquid, and transported the moistened mud to the nest entrance to build the sealing plug (Fig. A). The space in front of the outermost brood cell was not filled with soil resulting in an empty vestibule of 5-14 mm in length (median 7.0 mm).

The freshly sealed nest contained a single brood cell with an egg and a pollen loaf (Fig. 4C ). The pollen loaf was of orange colour and spherical shape, taking about half of the inner volume of the cell. It was very liquid and probably kept its shape due to surface tension and a significant amount of pollen covering it as suggested by the fact that it immediately lost its shape during an attempt to extract it from the cell. The egg was deposited on the top of the pollen loaf and directed with its free end towards the cell plug; its size was about 2.7 × 0.8 mm. Other cells, dissected in autumn, contained prepupae hibernating in their self-spun cocoons (Fig. 4E, F ). The cocoon consisted of a single thin layer; it was whitish and had a slightly shining inner surface. There was no distinct area for air-exchange as known for many other osmiine bees with more complex cocoon structure ( Rozen and Praz 2016). Instead, the cocoon of H. astragali uniformly covered the whole inner surface of the cell including the inner side of the cell plug. The larval feces were deposited between the cell wall and the cocoon, where they were spread uniformly and sparsely. The prepupae were of deep yellow colour. There was a single generation, i.e., the progeny of the females nesting in May hibernated. Six prepupae were obtained in 2022 and observed. Two females and two males emerged in 2023, while two prepupae remained alive but did not pupate; they obviously continued hibernation for a second winter.

Cocoons of the kleptoparasitic wasp Sapyga caucasica Radoszkowski, 1880 ( Hymenoptera : Sapygidae ) (Fig. 4F ) were found in three of the 11 cells (27%). This wasp hibernates as an imago allowing for its immediate identification to the species level. Several individuals of S. caucasica were also observed in May inspecting the surface of the clay cliff where H. astragali was nesting.

Flower associations

In Tsudakhar, both new species were observed in the vicinity of a clay cliff along an unpaved road (Fig. 3B ). Here, flower-visiting imagines were exclusively recorded on flowers of Astragalus ( Fabaceae ). Two species of this genus were abundant and in flower during the observation period: Astragalus haesitabundus Lipsky and A. onobrychioides M. Bieb. Females and males of Hoplitis astragali as well as a single male of H. dagestanica were observed only on the flowers of the former species, whereas no visits to the flowers of the latter species were recorded. In the vicinity of Chirkey A. haesitabundus was also abundant and in flower, but here most females and males of H. astragali visited the flowers of another Astragalus species, A. bungeanus Boiss.

Figures

Figure 2. Hoplitis dagestanica sp. nov. A, C, E, G female B, D, F, H male A, B habitus in lateral view C terga 4 - 6 in dorsal view D antenna in front view E terga 1 - 2 from behind F antenna in top view G part of hind leg with inner tibial spur H sterna 5 - 6 and tergum 7 in ventral view.

Figure 3. Habitats of the two new species of the genus Hoplitis Klug, 1807 in Dagestan A clay cliff along dry riverbed 6 km northwest of Chirkey, a nesting site of H. astragali sp. nov. B clay cliff along unpaved road in Tsudakhar, the type locality of both H. astragali and H. dagestanica sp. nov.

Figure 4. Nesting biology of Hoplitis astragali sp. nov. A female closing her nest with a plug of mud B female inside her nest burrow C freshly sealed one-celled nest in lateral view showing a cell with pollen loaf and egg D closing plugs of two nests (the right one the same as shown in B) E two-celled nest in lateral view with hibernating prepupae F two nests (the same as in D) in lateral view with hibernating prepupae and cocoons of Sapyga caucasica Radoszkowski, 1880. Scale bars: 1 cm.