Perapion connexum (Schilsky, 1902)

Wanat, Marek, Podlussany, Attila & Schoen, Karel, 2012, Perapion connexum (Schilsky, 1902) (Coleoptera, Apionidae) in Central Europe, a case of plant expansion chase, ZooKeys 174, pp. 49-61 : 50-57

Perapion connexum (Schilsky, 1902)

Apion connexum Schilsky, 1902: 28.

Apion arcuatum Bajtenov, 1977: 15. Syn. by Legalov (1998).

Diagnosis.

Perapion connexum is of the same size and at first glance very similar to the common in Europe Perapion curtirostre , from which it differs in a black tone of body integument (evidently grey in curtirostre), almost cylindrical and distinctly curved rostrum (thickened in basal half and nearly straight in curtirostre, as in Figs 5, 6, 9, 10), narrower subconical head, puncturation of vertex rugose and indefinite, smaller and not elongate scutellum (scutellar shield), slenderer tarsi and in male metatarsi devoid of ventral spines. It strongly resembles Aizobius sedi in the colour of integument, but the latter species has different frons sculpture, with well defined punctures and long median fovea, pronotum distinctly rounded at sides, and a ventrally spined basal segment on all male tarsi. See the key to species of Perapion occurring in Central Europe given below.

Morphology.

Body length 2.0-2.3 mm.

Integument and vestiture. clearly black with slight “oily” glint (Fig. 1). Body covered with sparse and extremely fine white-semitransparent hair-like scales, on pronotum as long as diameter of the largest punctures, on elytral disc not longer than half interval’s width and unordered on intervals, not aggregated in any part of elytra, slightly denser on mesothoracic epimera and anepisterna, along metanepisterna condensed to form a thin white line. Entire body surface with dense microreticulation, scale-like and rough on head and the basal half of rostrum.

Rostrum in dorsal view subcylindrical with obtuse widening at antennal insertion, obscuredly punctured throughout, except distal third completely mat.

Head narrow, subconical, nearly as long as wide, about 1.5 × narrower than pronotum (Figs 7, 8); eyes gently convex; frons slightly depressed in middle, with a few indictinct strigae partly obscured by dense microsculpture; puncturation on vertex lacking or indefinite, rarely with few punctures much smaller than on pronotal disc; head ventrally between eyes evenly scale-like microsculptured, without irregular asperities.

Antennae short and thin, with large club nearly as long as six distal funicular segments combined, 2.10 –2.25× as long as wide, having fused segments with their circular rims incomplete (Fig. 2); pedicel 1.4 –1.6× longer than wide, twice as long as next segment, segments 2, 3 minute and weakly elongate, segments 4, 5 isodiametric, 6 sligthtly, and 7 markedly transverse.

Pronotum small, slightly shorter than wide, with weakly rounded sides, at base 1.1 –1.2× as wide as at apex, coarsely punctured, the punctures usually of 3-4 combined ommatidia size, with flat, heavily and somewhat roughly microreticulate interspaces; prescutellar fovea not wider than single puncture, as long as 3-4 neighbouring punctures combined.

Scutellar shield small, isodiametric (Fig. 7).

Elytra widest clearly behind mid-length, 1.6 –1.7× longer than wide, 3.4 –3.8× as long as pronotum, with deeply impressed catenulate-punctate striae, on elytral disc half as wide as intervals; intervals flat, barely punctate; specialised setae single on 7th and 9th interval.

Wing without radial window.

Ventrites. Metaventrite and abdominal ventrites I, II microreticulate and evently punctate, shiny, the punctures much smaller than on pronotal disc, well over a diameter apart from each other; abdominal ventrites III–V with strong, scale-like microsculpture.

Legs slender; profemur 0.80 –0.85× as thick as rostrum; protibia widening from base to apex, with obsolescent apical tuft of setae; tarsi slender, protarsus 3.15 –3.40× as long as wide; claws untoothed, thickened basally (Fig. 3).

Male. Rostrum slightly shorter than pronotum, 2.20 –2.35× longer than wide, in profile almost straight and somewhat wedge-like, distinctly narrowing apicad in distal half (Fig. 11). Antennal insertion at basal 0.38-0.42 of rostrum. Abdominal ventrite V very broadly rounded apically. Metatarsus unarmed. Pygidium half exposed, with very broad complete transverse sulcus. Terminalia only slightly different from those of Perapion curtirostre , mainly in more elongate tegminal plate and aedeagus. Sternite VIII broad, with very short and indistinct lobes. Sternite IX with slightly asymmetrical fork half as long as apodeme. Tegmen with phallobase as long as apodeme; tegminal plate fused, short, devoid of macrochaetae, with broadly and very deeply emarginate prostegium. Aedeagus short and flattened, with pedon about 4.5 × as long as wide, membranous tectum and free apophyses less than 0.2 × as long as pedon; endophallus finely and more or less evenly microspinose.

Female. Rostrum 1.00 –1.15× as long as pronotum, 2.60 –2.75× longer than wide, in profile distinctly curved and equally high along its length (Fig. 4). Antennal insertion at basal 0.35-0.39 of rostrum. Abdominal ventrite V narrowly rounded apically. Tergite VIII broad and strongly transverse, uniformly slerotized. Sternite VIII with large and broad basal arms. Gonocoxites less than 2.5 × longer than wide, without median string of sclerotisation; styli slightly elongate, shortly setose apically.

Material examined.

Poland (E): Stare Stulno (51.3714°N, 23.6628°E), 1 VIII 2000, 4 exs, 2 VIII 2000, 10 exs, 5 VIII 2000, 10 exs, 7 VI 2001, 1 ex., 31 VII 2001, 16 exs; Rudka nr. Wola Uhruska (51.2761°N, 23.6694°E), 15 VII 2002, 1 ex.; Wołczyny (51.4392°N, 23.6656°E), 6 VII 2002, 2 exs; Orchówek-Obłonie (51.5291°N, 23.5950°E), 7 VII 2002, 2 exs; Sobibór (51.4680°N, 23.6599°E), 6 VII 2002, 13 exs; Kosyń (51.3903°N, 23.5750°E), 12 VII 2002, 7 exs; Hniszów (51.2646°N, 23.7119°E), 15 VII 2002, 2 exs - all leg. et coll. MW.

Ukraine (W): Podolia: Zvenihorod at Dniester riv., 48.5500°N, 26.2833°E, 25 VI 1996, 2 exs; Kamyanets Podilskiy, 48.6667°N, 26.5667°E, 26 VI 1996, 2 exs - all leg. et coll. MW;

Hungary: Borsod-Abaúj-Zemplén county: Füzér, Hosszú-rét (48.5644°N, 21.4324°E), 21.VII.2005, 3 ex., leg. Hegyessy G & S; Alsószuha, Hideg-kút-völgy (48.3586°N, 20.5144°E), 17 VI 2003, 5 exs, leg. HG - coll. AP (2 ex) and KMS (3 exs); Zalkod, Erkecse (48.1818°N, 21.4541°E), 10.VII.1993, 1 ex, leg. HG - coll. KMS; Szalonna, Köszvényeskút (48.4612°N, 20.7086°E), 10.V.2007, 1 ex, leg. HG - coll. KMS; Tornaszentandrás: Mile-völgy (48.5066°N, 20.7853°E), 10.V.2007, 1 ex, leg. HG - coll. KMS; Mád, Becsek (48.1826°N, 21.3056°E), 10.IV.2008, 1 ex, leg. HG & AP - coll. AP; Taktaszada: Ökör-mező (48.1122°N, 21.1504°E), 11.VI.2008, 1 ex, leg. HG - coll. KMS.

Slovakia (S, E): Železné env., Tornaľa - Starňa (48.4167°N, 20.4000°E), 26 V 2006, 1 ♂, leg. et coll. T. Kopecký; Zemplínské Kopčany (48.5833°N, 21.8833°E), 14 VI 2000, 1 ♂ 1 ♀, leg. P. Boža - coll. S. Benedikt, 20 V 2002, 7 ♂♂ 7 ♀♀, leg. M. Mantič - coll. M. Mantič & KS; Turňa nad Bodvou (48.6000°N, 20.8667°E), 9 VI 2001, 1 ♂, leg. R. Fornůsek - coll. S. Benedikt.

Russia: Kursk, 1 ex.; Orel [Oryol], 3 exs; Nikitskoe near Voronezh, 1 ex. - all coll. F. Schubert (in Naturhistorisches Museum Wien). W Siberia: Novosibirsk Area, Kochenevo distr., 43 km WNW of Kochenevo, Sektinskoye Lake, 27.05.1998, leg. R. Dudko & A. Legalov, det. A. Legalov, 6 exs - coll. KS (2 ♂♂ 2 ♀♀) and M. Koštál (1 ♂ 1 ♀). Rostov reg.: Krasny Sulin distr.: Donleskhoz env. (47.8627°N, 40.2405°E), 12 VI 2004, 1 ex., leg. D. Kasatkin - coll. MW.

Kyrgyzstan: Chüy province: Ala-Archa valley (42.6000°N, 74.4833°E), ca. 30 km S of Bishkek, above 1300 m alt., 4 VI 2003, 3 exs., leg. R. Królik - coll. MW.

Distribution.

Austria?, Hungary*, Kazakhstan, Kyrgyzstan*, Moldova, Poland (E), Russia (Central and South European Territory, Western Siberia), Slovakia (S and E), Ukraine, Uzbekistan (first records herein marked with asterisk).

Biology.

Korotyaev (1987) collected this weevil from broad-leaved sorrel species. The senior author (MW) collected it in Ukraine by general sweeping of wet meadows in the Dniester valley, where an unidentified broad-leaved sorrel was abundant. Poiras (1998) identified the host plant as Rumex confertus Willd. and, indeed, in Poland the weevil was collected exclusively from this sorrel species. In the Udmurt Republic Dedyukhin (2009) confirms the same host plant, but he collected adults also from the sorrels resembling Rumex crispus L. The life cycle of Perapion connexum remains unknown, but the adults were in Poland mostly beaten in summer from mature infruitescences, which may indicate larval feeding on developing seeds or eventually in fruit petioles, rather than in thick main stem or leaf petioles. In Poland teneral beetles were observed since mid-July.

Comments.

Korotyaev (1987) reported a specimen from the collection of ZIN labelled “Austria”, which was then approximately 800 km distant from the westernmost known locality in Moldova. This outstanding record was ignored by the authors of subsequent Centraleuropean weevil catalogues ( Lucht 1987, Böhme 2005, Alonso-Zarazaga 2011), but in the light of our current findings and proximity of current Slovak and Hungarian localities, this opinion should be verified and the occurrence of Perapion connexum in Austria should be considered as likely, though obviously requiring confirmation with new data. Unfortunately, the information on distribution of its host plant in Austria is poor and equivocal. It was missing from the first two editions of Austrian Excursionsflora by Fritsch (1897, 1909), but it was noticed from Austria since at least mid-20th c. ( Tutin et al. 1964). Then Jalas and Suominen (1979) did not justify Austrian records of this sorrel, and they were consequently removed from the revised editions of Flora Europaea. Most recently the occurrence of Rumex confertus in Austria has been confirmed in the departments of Wien, Niederösterreich, Steiermark and Kärnten (Fischer et al. 2008), but the history of its invasion(s) remains unclear.

The occurrence of Perapion connexum in Poland, as based on the abovementioned data, was earlier generally announced by Wanat and Mokrzycki (2005), and further confirmed by Gosik (2006). Analogously, the weevil has been just placed on the list in Slovakia ( Benedikt et al. 2010). The range of this weevil in Poland seems still strictly limited to the southern section of the Bug River Valley, which constitutes there the country border between Poland and Ukraine, but one of the listed localities ( Kosyń) is situated ca. 18 km “inland” West of the river. Along the Bug River Valley the southernmost site is Gródek near Hrubieszów ( Gosik 2006) (lat/long approximately 50.79°N, 23.96°E), while the remaining seven sites are situated between Hniszów and Orchówek, which is the northermost locality of this species in Poland (51.5291°N, 23.5950°E). Searching for the weevil in 2002-2003 in similar sites rich of the host plant but laying North along the Bug valley, i.e. in Parośla nr. Sławatycze (51.8099°N, 23.6206°E), Mielnik (52.3328°N, 23.0225°E) and Kózki nr. Siemiatycze (52.3605°N, 22.8660°E), brought negative results. Nevertheless, in Russia the weevil was found up to 54.5°N in Ul’yanovsk ( Korotyaev 1987) and even 57°N in the Udmurt Republic ( Dedyukhin 2009) and the northernmost Siberian sites ( Legalov 2002), despite of continental climate. Thus the Lower Bug Valley seems to be the most obvious natural area for further spreading of Perapion connexum in Poland and presently limited range of the weevil there may indicate a stage of current invasion.

Rumex confertus is an invasive plant in Europe, and its natural range ends probably close to Southeastern Poland, in Southern Slovakia and Hungary ( Rechinger and Schreiber 1957, Tutin et al. 1964, Jalas and Suominen 1979, Dostál 1989, Jehlík et al. 2001). However, although it is known from the Bug River Valley in Poland since 1873 ( Eichler and Łapczyński 1892), its autochtonous status in Poland is doubtful. According to Trzcińska-Tacik (1963) and Tacik (1992), who studied distribution of this sorrel species in most detail, its natural range North of the Carpathians rather ends in Western Ukraine. Its spreading to the West of Poland started probably since 1950 ( Tokarska-Guzik 2005) and currently it appears a common plant in Poland east of the Vistula river, reaching even the Baltic coast to the North, and it has many diffused localities also in the Western Poland ( Trzcińska-Tacik 1963, Zając and Zając 2001, Stosik 2006). It extends its range widely also to the North, being probably introduced to Skandinavia with the Soviet army transports since the very early 20th century in Finland, and about mid 20th century in Norway and Sweden ( Snogerup 2000). It is now widespread also in Baltic countries and treated as invasive plant in Lithuania ( Gudžinskas 1999). The Southern stream of its invasion to Central Europe seems less active. The plant is still very rare in Czech Rep. with just a few isolated and ephemeral localities ( Jehlík et al. 2001) and, as stated above, it has quite similar status in Austria.

Following current distribution of the host plant, further expansion of Perapion connexum in Central Europe from the sites showed in Fig. 12 seems very likely especially through the territory of Poland, and it could be monitored quite easily by summer sweeping of mature inflorescences of Rumex confertus . The same method should be applied on stabilized localities of Rumex confertus in Austria to record its occurrence and expansion.