Stenancistrocerus (Paratropancistrocerus) obstrictus ( Morawitz, 1895 )

Fateryga, Alexander V., 2020, Nesting biology and distribution of Stenancistrocerus (Paratropancistrocerus) obstrictus (Morawitz, 1895) (Hymenoptera: Vespidae: Eumeninae), Zootaxa 4718 (4), pp. 591-600 : 593-597

Stenancistrocerus (Paratropancistrocerus) obstrictus ( Morawitz, 1895)

Odynerus obstrictus Morawitz 1895: 447–449 , ♀ ♂ (type locality: “Transcaucasia: Derbent” [ Russia]), lectotype (designated here): ♀, “Derbent” [ZISP] ( Figs 1–4 ).

Atropancistrocerus obstrictus: Blüthgen 1938: 461 ; 1939: 258, Caucasus.

Stenancistrocerus obstrictus: Giordani Soika 1970: 91 , Russia (Dagestan); van der Vecht & Fischer 1972: 58, Russia (Dagestan); Tobias & Kurzenko 1978: 170, Russia (Dagestan); Kurzenko 1981: 108, Russia (Dagestan, Volga Region), Transcaucasia; Aliyeva 2010: 57–59, Azerbaijan (Nakhchivan AR); Antropov & Fateryga 2017: 189, Russia (south of European part, North Caucasus), Transcaucasia.

Diagnosis. The species can be recognized among other Stenancistrocerus (Paratropancistrocerus) by presence of a distinct horizontal face of the propodeum and black postscutellum.

Material examined. Type material. Lectotype (designated here): Dagestan: Derbent, 1 ♀, leg. Faust (full labels are the following: “ Derbent. Faust. ”, “к. Ф Моравица [coll. F Morawitz]”, “ obstrictus F. Mor. ♀.”, “typ F. Morawitz det.”, “ Lectotypus Odynerus obstrictus Mor. ♀ des. Kurzenko 1976” [red label]) [ ZISP] ( Figs 1–4 ); the lectotype was designated by N. V. Kurzenko in his thesis manuscript (1978: 276), but never published . Paralectotype: Dagestan: Derbent, 1 ♀, leg. Faust (full labels are the following: “ Derbent Faust. ”, “к. Ф Моравица [coll. F Morawitz]”, “ Odynerus obstrictus F. Mor. ♀ ”, “ Paralectotypus ♀ ” [red label]) [ ZISP] . Additional material. Russia: Astrakhan Prov.: Astrakhan, 3. VI .1915, 2 ♂; ibid., entomological station , 3. VI .1915 , 1 ♀, coll. Shestakov [ ZISP]; Liman Distr. , 13 km S Liman (45°40′N, 47°14′E), 25.VII.2015, 1 ♀, 6 ♂, leg. S.B., V . L., M.M., M.P. [ CAFK, CFUS]; ibid ., 5. VI .2016 , 4 ♀, 6 ♂, leg. M.M.; Yenotayevka Distr., vicinity of Volzhskiy (46°58′N, 47°32′E), 6.VII.2017, 1 ♀, leg. M.M. [ CFUS]; ibid ., 8.VII.2018, 1 ♂, leg. M.M., V . L., M.P. [ CAFK]. Kalmykia: Yashkul Distr. , 23 km E Yashkul (46°09′N, 45°39′E) , 17.VII.2015, 1 ♂, leg. S.B., V . L., M.M., M.P.; ibid ., 31. V.2016, 1 ♀, 5 ♂, 1. VI .2016 , 13 ♂, leg. M.M. [ CFUS]; Chernozemelskiy Distr., 17 km SWW Artezian, Kuma River (44°48′N, 46°27′E), 18.VII.2015, 1 ♂, 19.VII.2015, 4 ♀, 4 ♂, 20.VII.2015, 7 ♀, 12 ♂, leg. S.B., V . L., M.M., M.P. [ CAFK, CFUS]; Chernozemels- kiy Distr., 12 km W Artezian, Kuma River (44°56′N, 46°30′E) , 7.VII.2018, 1 ♀, leg. Y.A., K.F., V . L., M.M., M.P. [ CAFK]. Stavropol Terr.: Kuma River bank , 24.VII.2004, 1 ♀, leg. N.B. Vinokurov [ CAFK] . Dagestan: Tarumovka Distr. , 9 km SSE Kochubey (44°19′N, 46°36′E) , 21.VII.2015, 4 ♀, 6 ♂, 22.VII.2015, 16 ♀, 14 ♂, leg. S.B., V . L., M.M., M.P. [ CAFK, CFUS]; Tarumovka Distr. , 23 km N Kochubey (44°36′N, 46°35′E) , 17. VI .2018 , 1 ♀, 1 ♂, leg. Y.A., K.F., V. L., M.M., M.P.; Tarumovka Distr. , 13 km NE Kochubey (44°27′N, 46°42′E) , 18. VI .2018 , 1 ♀, 1 ♂, leg. Y.A., K.F., V. L., M.M., M.P.; Tarumovka Distr. , 20 km SSE Kochubey (44°15′N, 46°40′E) , 6.VII.2018, 3 ♂, leg. Y.A., K.F., V . L., M.M., M.P. [ CAFK]; Tarumovka Distr., Kuma River bank (44°56′N, 46°29′E) , 3. VI.2016, 5 ♀, 9 ♂, 4. VI .2016 , 3 ♀, 3 ♂, leg. M.M. [ CAFK, CFUS]; Kizlyar Distr., 12 km SSW Kizlyar, Novy Terek River (43°45′N, 46°40′E), 23.VII.2015, 1 ♀, leg. S.B., V . L., M.M., M.P. [ CFUS]; Kizlyar Distr. , 10 km SE Staroterech- noye (43°47′N, 47°33′E) , 19. VI .2018 , 1 ♀, leg. Y.A., K.F., V. L., M.M., M.P.; Kizlyar Distr. , 3 km SW Novoter- echnoye (44°00′N, 47°20′E) , 20. VI .2018 , 2 ♀, 5 ♂, leg. Y.A., K.F., V. L., M.M., M.P. [ CAFK]; Derbent Distr., Ka- myshchay River valley (41°54′N, 48°13′E) , 11. VI.2017, 1 ♀, 12. VI.2017, 1 ♀, 14. VI .2017 , 1 ♂, leg. M.M. [ CAFK, CFUS]; ibid., on Tamarix hohenackeri , 13. VI .2018 , 3 ♀, leg. A.F.; ibid., on clayey cliff near roadside, 13. VI .2018 , 1 ♀, leg. A.F.; ibid., from nests, 28.V–15. VI .2019 , 5 ♀, 7 ♂, leg. A.F.; Untsukulskiy Distr. , 3 km NNW Maydanskoye (42°38′N, 46°57′E), 1. VI .2019 , 1 ♂, leg. M.P., V. L. [ CAFK]. Armenia: Syunik Prov., Meghri , 29. V .1977 , 2 ♀, leg. Yu.A. Pesenko [ ZISP]. Azerbaijan: Sabirabad, Arax River , 2. VI .1929 , 4 ♂, leg. S. Kudrjavtsov [ ZMMU]. Country uncertain: Caucasus , 1 ♂, leg. Steven [ ZISP].

Distribution. Russia (Astrakhan Prov., Kalmykia, Stavropol Terr., Dagestan), Armenia, Azerbaijan. The species was omitted from the “Fauna Europaea” database ( Gusenleitner 2013b).

Bionomics. Nesting substrate. All 10 nests of Stenancistrocerus obstrictus were built by the females on a vertical clayey cliff facing south ( Fig. 5 ). The nests were distributed not very compactly; the distance between them varied from approximately 0.5 to 1.5 m. Two different groups of nests were observed: 1) with six nests in 2018 and one nest in 2019; 2) with three nests in 2019. The distance between them was 45 m. At first glance, the nests looked to be horizontal burrows surmounted by laced earthen turrets (= chimneys) curved downwards. More precise inves- tigation, however, revealed that the nests were actually not burrows. Instead, they were built in preexisting holes; such as traces of rotten roots or burrows of other invertebrates.

Nesting activity. Four stages of female nesting activity were observed during the present study: searching for a place for the nest, turret construction, uncertain building work inside the nest, and provisioning. Searching for a place for the nest, a female made slow zigzag flight several centimeters from the cliff, landed near every hole in its surface ( Fig. 6 ), and penetrated each hole to investigate it. This behavior took very much time. Three females were observed searching for a place for the nest during two days and none of them finished this behavior. The investigation of each hole usually took several minutes. Initiation of the nesting was not observed.

Turret construction was observed for four females. The nest turret of one of them was accidentally broken during the observations and the female started to repair it. Most observations were made on this female but three others had similar habits. The female collected building material outside the nest, approximately 1 m from its entrance. She landed on the cliff surface and regurgitated on it a small portion of liquid. Then, she mixed it with the clay and formed a mud pellet using her mouthparts and holding it also with the fore legs ( Fig. 7 ). After that, the female returned to her nest, landed on the turret, and started to transform the pellet to a laced pattern. During this activity, she used her frons and mandibles for the building work while all legs were used to hold on the turret ( Fig. 8 ). After several portions of mud had been used for the turret, the female flew away for liquid. It was impossible to ascertain the source of the liquid using by the wasps for building. Females were not recorded either on water at the water furrow located not far from the nesting site or on leaves of the succulent plants abundant hereabouts. Each portion of liquid was used to make 3–5 mud pellets. The female repaired the turret during 65 min. and this turret appeared the longest among all observed ones, namely 2 cm long by linear distance from the base to the top ( Fig. 9 ). The inner diameter of all turrets was about 3.0–3.5 mm. The turrets had more laced structure at their distal ends while they became more solid towards the base ( Figs 8–9 ).

Two females were also observed carrying mud pellets into their nests without using them for the turret construction. Every time after the pellet had been carried, a female made unknown building work inside the nest during several minutes. Three nesting females were observed at the provisioning stage of their nesting. They carried tiny larvae of unidentified weevils ( Coleoptera : Curculionidae ). It was impossible to ascertain the location of the hunting site, as well as the host plant of the prey. All attempts to find living conspecific larvae on the surrounding vegetation failed. Sealing of the nest was not observed but evidently females completely dismantled nest turrets during this action. Complete nests were always sealed by final plugs which were indistinguishable from the surrounding ground (see Fig. 13 D–F).

Structure of the nests. Nests of Stenancistrocerus obstrictus were located in holes which were 2.5–10.5 cm in length and 3–4 mm in diameter ( Fig. 13 ). All nests had linear structure; they were made as a row of 3–10 cells separated by thin mud partitions. The nests began either directly from the end of the hole or at a distance from it. In the latter case, the space between the end of the hole and the first nest cell was often filled with dust, fragments of various dead insects, and remains of other wasp and bee nests. Lateral walls of the cells were lined with a thin layer of mud taken from outside the nest. The same layer was also present along the whole hole in incomplete nests ( Fig. 13 A–C), as well as in the vestibular cell which was present in one complete nest ( Fig. 13E ). Unfortunately, it was impossible to ascertain whether the wasp lined the nest hole with mud before turret construction or after it. The cells were 5–9 mm in length. The final plug of the nest was much thicker than the partitions between the cells; in one nest it was consisted of two parts ( Fig. 13F ). Inner cells, neighboring to the end of the hole were used for female progeny while outer cells were used for males (see below).

Provision. Last cells in each nest dissected in June, 2018 contained provision and an egg or a young larva. Provision was the mass of numerous minute curculionid larvae glued together ( Figs 10–11 ). It was hard to calculate the number of these larvae in a cell because it was impossible to separate them from each other without damaging. Their number, however, amounted to several dozens.

Immature instars and development. One egg of Stenancistrocerus obstrictus was observed; its size was 1.2×0.4 mm. It was suspended by the female wasp on the cell wall with a filament ( Fig. 14 ). When the larva hatched from the egg, it immediately began feeding on the stored prey. After consuming all provisions, it spun a cocoon. The duration of the feeding and the cocooning was not documented. The cocoon had one layer tightly adhered to the inner cell walls, bottom, and plug, except a small area with prey feces ( Fig. 14 ). It was whitish and nontransparent. The cocoon evidently consisted of numerous pressed filaments, without any liquid substance penetrating into cell walls. The meconium was located inside the cocoon. After it was discharged onto the bottom of the cell, the larva passed to the prepupal stage and hibernated ( Fig. 12 ). The pupation occurred next year in May.

Most of the immature instars from the nests dissected in June, 2018 died during transportation. Just two females and three males emerged in 2019 from a total of 18 cells. All progeny from the nests delivered to the laboratory with large lumps of clay survived. In one nest, a female emerged from the first cell and two males emerged from the second and the third ones. In another nest, two females emerged from the first and the second cells while two males emerged from the third and the fourth ones. The progeny in the nest dissected in 2019 also began to hibernate. Thus, the species is obviously univoltine. According to the data of the studied collections, adult wasps (both females and males), however, are active from the end of May to the end of July (see “Material examined”). Such a long period of activity could be probably related to the rate of the nesting. Particularly, duration of searching for a place for the nest is very long in this species due to scarcity of suitable preexisting holes in clayey cliffs.

Reproductive success. In the complete nests, 11 cells (92%) were successful among 12. Just the first cell in the nest dissected in 2019 had been robbed by an unknown invertebrate predator penetrating into it from the end of the nest hole. No parasites and associates were found in the nests.

Adult feeding. Three females of Stenancistrocerus obstrictus were collected feeding on flowers of Tamarix hohenackeri in the morning (8.30–10.30, solar time).

Male behavior. No males were observed either on flowers or at the nesting site.

Figures

FIGURES 1–4. Odynerus obstrictus Morawitz, 1895, ♀, lectotype. 1, habitus in dorsal view. 2, habitus in lateral view. 3, head in frontal view. 4, labels.

FIGURES 5–12. Bionomics of Stenancistrocerus obstrictus (Morawitz, 1895). 5, nesting site. 6, a female searching for a place for the nest. 7, a female collecting earth and forming a mud pellet. 8–9, a female building the entrance turret of her nest at different stages of its construction. 10, prey stored in a cell. 11, the same, ejected from the cell. 12, four cells of a dissected nest with hibernating prepupae. Scale bars = 5 mm.

FIGURES 13–14. Schematic plans of nests, cells, and the immature instars of Stenancistrocerus obstrictus (Morawitz, 1895). 13, plans of six dissected nests, lateral view (A–C, incomplete nests dissected at the provisioning stage; D–F, complete nests sealed by the females; 1–10, cell numbers). 14, cells with an egg and a prepupa in the cocoon, lateral view (A, mud; B, meconium; C, cocoon; D, prey feces). For clarity, the cocoon is shown as detached from the cell walls, whereas in reality it tightly adheres to them.