Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf ISOPERLA PROKOPOVI, A NEW PRESUMEDLY PARTHENOGENETIC STONEFLY FROM CRIMEA (PLECOPTERA, PERLODIDAE) L.A. Zhiltzova1 and P. Zwick2 1 Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia E-mail: [email protected] 2 Schwarzer Stock 9, D-36110 Schlitz, Germany E-mail: [email protected] ABSTRACT Isoperla prokopovi sp. n. from Crimea is described from females, larvae, and eggs. Males or male larvae were not found, despite concerted efforts. The species is therefore believed to be parthenogenetic. The life cycle appears to be univoltine, possibly with a long egg diapause. The thick egg chorion differs from other Perloidea in that it disintegrates in KOH. Isoperla prokopovi is an isolated species without apparent close relatives among the West Palaearctic Isoperla spp. Keywords: Taxonomy, Ukraine, Crimea, new species, parthenogenesis, life cycle INTRODUCTION Zoological Institute, Russian Academy of Sciences, For many years, unusually large Isoperla sp. larvae St. Petersburg). Paratypes: 1♀, 7.06.89, Crimea, Riv. were collected in various streams on Crimea, mainly Small Salgir (Malyi Salgir). Sample II. L. Zhiltzova. in the Great Canyon of Crimea, near the junction of 2♀, 9 last instar L, Crimea, end of May 2008, brook the rivers Almachuk and Auzun-Uzen'. In 2009 G. Almachuk (basin of river Bel'bek) G. Prokopov, plus Prokopov succeeded to rear adults, which were all 1 exuviae without type status. 5 last instar L, 29.05.89. females. Numerous attempts by G. Prokopov to Crimea. Spring Hasta-Bash. L. Zhiltzova [in collect or rear males or to detect male larvae failed. Zoological Institute, Russian Academy of Sciences, We therefore assume that the new species lacks St. Petersburg, except 1♀, 4 last instar larvae in coll. males completely and is parthenogenetic. Zwick]. Additional material. 13 young L, River Guva Isoperla prokopovi Zhiltzova et Zwick, sp. n. (Derekoika) upper part (near Yalta), 14.10.2011 [G. (Figs. 1-10) Prokopov, coll. Zwick]. 16 young L, River Auzun- Uzen' (Grand Canyon of Crimea), 18.11.2011 [G. Material examined. All specimens are from Ukraine, Prokopov, coll. Zwick]. Autonomous Republic of the Crimea. Additional material communicated by G. Prokopov, Holotype ♀, 15.06.2004 Riv. Small Salgir (Malyi collectors' names in square brackets. Spring Hasta-Bash Salgir). Adult reared in cage. G. Prokopov, adult (under Ai-Petry mountain): 3L, 29.05.1984 [G. with exuviae and eggs on microscope slide [in Kiseleva]; 6L, 19.04.1988 [L. Zhiltzova]; 11L, 2 Corresponding author; e-mail-address: [email protected] Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 37 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf 29.04.1988 [L. Zhiltzova]; 5L, 29.05.1989 [L. Prokopov]; 25L, 10♀, 30.05.2009 [G. Prokopov]. Riv. Zhiltzova]; 2L, 31.05.1999 [G. Prokopov]; 2L, Kokkozka, 2L, 22.08.2000 [G. Prokopov]. - River 5.06.2010 [G. Prokopov]. - River Guva (Derekoika) Alma basin (upper part), spring near Koz’ma and upper part (near Yalta): 20 juv. L, 19-21.09.1999 [G. Damian monastery, 2L, 26.06.2001 [G. Prokopov]. Prokopov]; 6L, 23-25.05.2000 [G. Prokopov]. - River River Salgir basin: Riv. Angara (upper part of Salgir Ulu-Uzen’ Alushtinskyi basin (near Alushta): Riv. river): 1L, 6.06.1984 [G. Kiseleva]; 1L, 25.05.2002 [G. Uzen’-Bash, 1L, 7.05.2000 [G. Prokopov]; Riv. Sofu- Prokopov]; Riv. Kizil-Koba (upper part of Salgir Uzen’, 2 juv. L, 31.10.1999 [G. Prokopov]. - River river): 2L, 14.04.88 [L. Zhiltzova]; 1L, 4.05.1988 [L. Eastern Ulu-Uzen’ (near village General’skoe): 1L, Zhiltzova]; 1L, 17.02.2001 [G. Prokopov]; 2L, 11.08.1964 [R. Kazlauskas]; 4 juv. L, 31.10.1999 [G. 25.05.2006 [G. Prokopov]; 2L, 25.05.2007 [G. Prokopov]; 1 juv. L, 28.07.2000 [G. Prokopov]; 7 juv. Prokopov]; Riv. Small Salgir (tributary of Salgir L, 15.10.2000 [G. Prokopov]; 1L, 1.05.2001 [G. river) near vill. Drujnoie: 2L, 20.03.2003 [G. Prokopov]. - River Belbek basin (upper part), Riv. Prokopov]; 1♀, 5L, 20.06.2004 [G. Prokopov]; 6L, Sary-Uzen’: 2L, 22.04.1988 [L. Zhiltzova]; 2L, 28.05.2006 [G. Prokopov]; 6L, 01.06.2007 [G. 1.05.2002 [G. Prokopov]. - Riv. Auzun-Uzen’ Prokopov]; Riv. Burulcha (tributary of Salgir river) (Rozovaja) (Grand Canyon of Crimea): 4L, 11.08.1964 near village Mejgor’e, 4L, 26.04.1988 [L. Zhiltzova]; [R. Kazlauskas]; 3L, 27.04.1988 [L. Zhiltzova]. Spring Riv. Suat (tributary of Burulcha river) upper part: 2 Almachuk: 9L, 22.04.1988 [L. Zhiltzova]; 2L, juv. L, 3.09.1999 [G. Prokopov]; 4L, 1.05.2001 [G. 5.05.2003 [G. Prokopov]; 3♀, 17L, 5.05.2003 [G. Prokopov]. 1 2 3 4 Figs. 1-4. Isoperla prokopovi sp. n., adult female. 1-2. Examples of the variable wing venation. 3. Head and thorax. 4. Abdominal tip, ventral view. Not to scale. Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 38 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf The material is in the respective collectors' marks, appendages light brown. Head in front of the collections, except specimens taken by G. Kisela M-Line yellow, behind it brown to the occipital which are kept in the collection of the Zoological suture, with small paler areas laterally from the Institute of the Russian Academy of Sciences. paired ocelli and the tentorial calluses. Occiput light except darker muscle attachment scars. Small DESCRIPTION paramedian and large caudolateral areas at the Adult female. (Figs. 1-4). Body length 13.5 – 16.0 posterior margin of head brown. mm, length of forewing 12 – 15 mm. External Pronotum light brown with wide pale median morphology typical of the genus. band and dark brown muscle attachment scars. Wings clear with thick brown veins in forewing, Mesonotum with light prescutum and a light brown paler and finer in hindwing. Forewing with 8 – 10 median area in anterior part of scutum, remainder branches entering the wing margin between R and dark brown. The abdominal integument seems to be Cu, details variable (Fig. 1) between specimens as light brown but appears dark brown because of egg well as between the two wings of a given specimen. masses visible through the integument. Abdominal For example, a large extra cell may be formed by a sterna mainly pale yellow, except brown basi- and crossvein between Rs and M which is only furcasterna and brown hind areas of posterior occasionally present (Fig. 1, forewing). Also, abdominal segments. branches of Rs and M may fuse for a short distance Sternite 8 with short subgenital plate occupying and then separate again (Fig. 2, hindwing). In the the entire width of segment, with U-shaped medial hindwing, A2 and A5 branched. notch. Sternite 9 brown, 10 pale. Paraprocts wide Head very large, area behind occipital suture with concave medial edge producing a narrow apex. unusually large, appearing inflated. Genae in dorsal Ventrally sclerotized, dorsally unsclerotized. Cerci view about as long as eyes, convex, protruding. with ca. 15-17 segments, segment length changing Antennae and mouthparts lack structural from half as long as wide at base to about 4 times particularities. longer than wide at apex. Setal ring on each segment Ground colour of body yellowish, with brown with one or a few very long ventral setae. Fig. 5. Isoperla prokopovi n. sp., last instar larva (photography by G. Prokopov). Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 39 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf Egg. (Fig. 6). Abdomen of last instar larvae and adult In optical cross section and in egg fragments the females packed with fully formed eggs. Egg egg shell consists of an inner, apparently subspherical, cross section circular, ca. 365 µm long, structureless layer where the diameter abruptly longer than wide largely because of the projecting decreases at the level where the eclosion line would collar. The egg contents is ca. 0.014 mm³. Collar with occur in other Isoperla species. Under the operculum irregular longitudinal crests, recurved edge irregular. and above the anchor attachment inside the collar the Anchor large, mushroom-shaped. Micropyles not inner layer is very thin. The outer layer is densely found. Chorionic surface irregularly and minutely and finely radially striated and appears spongy. The finely punctate. Operculum with slightly larger chemical nature of egg shell is unknown (see punctations in the usual hexagonal arrangement left discussion). by follicular cells. 7 6 8 9 10 Figs. 6-10. Isoperla prokopovi n. sp., egg and last instar larva. 6. Egg. 7. Habitus. 8. Left mandible, ventral view; an arrow points at the dense patch of small spicules. 9. Left maxilla, ventral view. 10. Labium, ventral view (courtesy G. Prokopov). Only Figure 6 to scale. Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 40 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf Last instar larva (Figs 5, 7-10). Body length 15-19 Abdomen banded. Pale sides and a series of mm, head capsule width ranging from 3.0-3.8 mm round maculae along midline separated by two (Fig. 14). External morphology typical of genus brown paramedian bands. Borders of the dark areas Isoperla (Zwick 2004). on each segment medially and laterally concave. The Dorsum yellow with dark brown marks. Anterior large pale circular areas in the centre are divided by a portion of head yellow. Median round pale mark greyish median band. Tergite 10 essentially pale. posterior to transverse dark band behind the M-line Ventrum largely pale. Mouthparts, antennae, legs and anterior to the occipital suture, smaller light and cerci yellowish to light brown. areas lateral to ocelli. Oblique dark band extending Mouthparts generally similar to congeners. Left from behind the eyes and posterior to occipital mandible dorsally, behind the cusps and in front of suture extending to posterior margin of head the setal band, with a dense patch of spicules arising meeting it paramedially. Anteromedially the band from cuticle with polygonal pattern. The right has several extensions into the pale central area mandible has the polygonally structured area but no behind the occipital suture. Caudolateral corners of spicules. Lacinia with two large cusps basally from head pale. which begins a row of about 10-12 large spines. The Pronotum dark with narrow pale edge. A wide row is locally bilinear and blends basally with an median line widens and forms a pale central area elongate densely setose area. Because of transitions resembling a clover leaf. Anterior part of meso- and in shape and size, the number of lacinial spines metanotum with pale median strip flanked by cannot be precisely determined. Dorsally between paramedian dark bands connected to oblique bands the two cusps stand 3-4 very slender, hyaline sensory over the wing pads. All bands with lobes and setae. Galea dorsally with several thin slender setae, excisions, shape complex (Figs. 5, 7). a few smaller hairs along ventral edge. Fig. 11. Isoperla prokopovi n. sp., distribution map (courtesy of G. Prokopov). Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 41 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf Setation. A curved plurilinear band of short spines Intercalary setae numerous but smaller. The in the brown occipital area is medially widely exceedingly fine procumbent hairs typical of Isoperla interrupted. Femora and tibiae with, antennae and larvae are dark on the fore body but pale on the cerci without long silky hair fringes. The slender abdomen, same as the other setae. pointed marginal setae on sides of pronotum, along Etymology. It is our pleasure to name this lateral edges of wingpads and along rear margins of remarkable new species in the honour of Grigoriy abdominal tergites are unusually short, shorter than Prokopov, Simferopol, in recognition of his valuable the intersegmental areas covered with chloride cells. contributions to our study. Fig. 12. Isoperla prokopovi n. sp., typical habitat at the confluence of rivers Auzun-Uzen’ and Almachuk, Grand Canyon of Crimea (photography by G. Prokopov). Distribution and biology. coexists with, for example, Siphonoperla taurica Isoperla prokopovi sp. n. inhabits the upper sections (Pictet) (Plecoptera), Baetis milani Godunko, of rivers on the northern and southern main slopes of Prokopov & Soldán, Electrogena braaschi (Sowa) the Crimean Mountains between 400 and 900 m a.s.l. (Ephemeroptera), Agapetus ajpetriensis Martynov, (Fig. 11). The species occurs where the stream bed is Plectrocnemia intermedia Martynov, Silo alupkensis rocky and the current fast, at water depths of 0.2-0.5 Martynov (Trichoptera), the blackflies Nevermannia m (Fig. 12). The mineralization of water fluctuates brevidens (Rubtsov), N. chodakovi (Panchenko), N. between 340 and 700 mg/l. The dominant ions are karajimae (Panchenko), N. tauricum (Rubtsov), the НСО3- (177-300 mg/l) and Са2+ (44-110 mg/l). Water beetle Hydraena chersonesica Jäch, Diaz & Przewozny, temperature at these localities fluctuates from 6°C to and Dugesia gonocephala taurocaucasica Porfirieva 20°C. The inhabited sites may have no surface flow (Tricladida) (Prokopov 2004). for two to three months in summer, beginning in Life cycle. (Figs. 13, 14). The list of material July. However, the subsurface flow continues. distinguished juvenile larvae, larvae without Isoperla prokopovi is part of the epi- and specification, and adults. The collection data were metarhithral community of the Crimean rivers. It classified as falling into the 1st or 2nd half of the Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 42 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf Figs. 13, 14. Isoperla prokopovi n. sp. 13 (top). Seasonal occurrence of numbers of juvenile larvae, larvae, and adults as evidenced by the lists of material studied. 14 (bottom). Frequency of size classes (HCW, head capsule width) among larvae collected in October / November 2011, and among the available last instar larvae. respective month. Numbers collected per half month were females. Twenty-nine young larvae (head were pooled, irrespective of year or site of collection. capsule width 1.0-2.4 mm, body length 4.2-10.3 mm) The seasonal distribution of the different life stages taken in October and November 2011 all exhibited suggests the life cycle is univoltine. The size secondary female characters. spectrum of larvae collected in October-November We are therefore convinced that males have not 2011 agrees perfectly with this. Larvae appear to been overlooked, as might happen if the species were hatch from eggs in the middle of year and grow to strongly sexually dimorphic. Isoperla difformis last instar and adulthood by May-June the next year. (Klapálek) offers an example. Its macropterous It is unknown whether the hatchlings were from females are readily found in littoral vegetation but freshly laid eggs or from eggs that had spent much the much smaller micropterous males are fast time in diapause. Direct fast development is runners dwelling mainly on the ground. Male larvae improbable in view of a general positive relationship of I. difformis (and other Perlodidae that lack between egg volume and length of development secondary male sexual characters) resemble juvenile time. The eggs of I. prokopovi are larger than those of specimens, except in the absence of secondary female other Perloidea which require more time to develop characters. Females can be recognized long before (Gillooly & Dodson 2000) than remains between they attain half final body size, several moults before presence of adults and appearance of the new the last instar (Zwick & Zwick 2010). The setal fringe generation of I. prokopovi. A long egg diapause on sternite 8 is medially interrupted, and, in slightly appears probable since it is not unusual among larger individuals, a minute scar of the prospective Perlodidae, also in European Isoperla spp. (Schwarz genital opening appears in the anterior third of 1970, Lillehammer 1987). sternite 8. This scar moves stepwise back at moults Notes and discussion. Isoperla prokopovi seems to be until it reaches the caudal segment edge (Zwick & parthenogenetic. All available large larvae and adults Zwick 2010). Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 43 Zhiltzova, L.A. and P. Zwick. 2012. Isoperla prokopovi, a new presumedly parthenogenetic stonefly from Crimea (Plecoptera, Perlodidae). Illiesia, 8(04):37-44. Available online: http://www2.pms-lj.si/illiesia/Illiesia08-04.pdf We know of no other Perlodidae emerging with Hébdomadaires des Séances de l'Académie des fully developed eggs. We found no micropyles in the Sciences, 246:1100-1102. eggs. If they indeed lacked them our assumption of Gillooly, J.F. & S.I. Dodson. 2000. The relationship of parthenogenesis would be strongly supported. In egg size and incubation temperature on eggs of other Perloidea, the micropyles are easily embryonic development time in univoltine and seen on the clean chitinous chorion that remains after multivoltine aquatic insects. Freshwater Biology, the egg content was removed in cold KOH. However, 44:595-604. the eggs of I. prokopovi behaved in a unique way. The Harper, P.P. 1973. Emergence, reproduction and shell was hardly more resistant than the egg content growth of setipalpian Plecoptera in Southern to treatment in cold KOH. Within an hour it turned Ontario. Oikos (Copenhagen), 24 (1):94-107. into a shape- and colourless mass of approximately Illies, J. 1955. Steinfliegen oder Plecoptera. In: Dahl, hexagonal small fields, each surrounded by some F. (ed.), Die Tierwelt Deutschlands und der gelatinous material. Later the egg fell completely angrenzenden Meeresteile, 43:I-IV; 1-150. apart. It seems to differ structurally and/or Lillehammer, A. 1987. Diapause and quiescence in chemically from known eggs of other Perloidea (for eggs of Systellognatha stonefly species example, Rosciszewska 1991). (Plecoptera) occurring in alpine areas of Norway. There is no confirmed case of natural Annales de Limnologie, 23:79-184. parthenogenesis in stoneflies but species of which Prokopov, G.A. 2004. Trophic relations in many females but no or very few males are known communities of macrozoobenthos fauna in (for example, Baikaloperla spp.; Zhiltzova 2003) are epirhithral of the rivers of Crimea. Uchenye probably at least facultatively parthenogenetic. zapiski TNU. Series: Geography. Vol. 17 (56). No Parthenogenetic development of eggs during 3:91-98. laboratory incubation is known to occur (Degrange Rosciszewska, E. 1991. Ultrastructural and histochemical 1958, Harper 1973). studies of the egg capsules of Perla marginata Affinities. Isoperla prokopovi is an isolated species (Panzer, 1799) and Dinocras cephalotes (Curtis, without close relatives in the West Palaearctic fauna. 1827) (Plecoptera: Perlidae). International Journal The venation of its front wing is richer than in other of Insect Morphology and Embryology, 20:189- European Isoperla spp. which have only 2 branches of 204. Rs, except I. difformis which may have three (Illies Schwarz, P. 1970. Autökologische Untersuchungen 1955). None of the other species has a subgenital zum Lebenszyklus von Setipalpia-Arten plate as wide as the segment, and none has a large U- (Plecoptera) Teil II und Schluß. Archiv für shaped notch in it. At first glance, the larva reminds Hydrobiologie, 67 (2):141-172. one of genus Bulgaroperla certainly also because of its Zhiltzova, L.A. 2003. Plecoptera Gruppe Euholognatha. large size.The shortness of larval pilosity is unique Russian Academy of Sciences, Zoological among Isoperla, and so are shape and chorion Institute, St. Petersburg, 537 plus 7 unnumbered structure of the egg. pages. Zwick, P. 2004. Key to the West Palaearctic genera of ACKNOWLEDGMENTS stoneflies (Plecoptera) in the larval stage. We thank G. Prokopov for contributing much of Limnologica, 34:315-348. the studied material, for information on details of Zwick, P. & H. Zwick. 2010. Life history and habitat, for the colour photographs, and the development of Dictyogenus fontium (Plecoptera: distribution map. Linguistic help by an anonymous Perlodidae) in two thermally contrasting streams reviewer and suggestions by D. Murányi improving at Lunz am See, Lower Austria. – pp.:459-475 in the discussion are much appreciated. Denisia 29, Festschrift zum 75. Geburtstag von Hans Malicky, 478 pp. REFERENCES Degrange, C. 1958. Premiers cas de parthénogenèse Received 30 March 2012, Accepted 17 April 2012, Published 24 chez les Plécoptères. Comptes Rendus April 2012 Illiesia – http://www2.pms-lj.si/illiesia/ Volume 8 – Number 4 – Page 44