Coelichneumon torsor (THUNBERG)

Tereshkin, A. M., 2013, Taxonomic notes about ichneumon fly Coelichneumon torsor (THUNBERG 1822) and illustrated, Linzer biologische Beiträge 45 (1), pp. 913-927 : 915-919

Coelichneumon torsor (THUNBERG) (Plate 1, 2)

Ichneumon torsor THUNBERG 1822 - Mém. Acad. Imp. Sci. St. Pétersburg 8: 256.

Ichneumon torsor: THUNBERG 1824 - Mém. Acad. Imp. Sci. St. Pétersburg 9: 297.

Coelichneumon torsor: RIEDEL 2008 - Entomofauna. 29 (12): 191-192.

M a t e r i a l e x a m i n e d: Byelorussia, Beresina Nat. Reserve, Postrezh’e, 54 o 38 ’ 08.78 ’’ N, 28 o 21 ’ 08.37 ’’ E, Pinetum sphagnosum, 42, 270, 1987-1998, A.Tereshkin leg.

M o r p h o l o g y:

F e m a l e

F l a g e l l u m: Stout, bristle-shaped, with 41 segments, with white annulus on segments 5-11, beyond white annulus strongly widened and flattened ventrally; first segment short, only 1,3 times longer than width at apex from lateral, already segment 4 square; last but one segment square; most broad segment ventrally 2,4 times wider than breadth. Flagellum 1,6 times shorter than the front wing and 2,7 times shorter than body length.

H e a d Head contour from front slightly narrowed downwards, temples from front visible almost up to middle of eye, head slightly transversal, 1,2 times wider than height, genae short, 7 times shorter than height of eye; head from above transversal, 1,7 times wider than length on an external contour. Vertex from lateral gradually slanting down to occipital carina; temples long, 1,3 times longer than longitudinal diameter of an eye at the middle, not narrowed downwards, from above roundly, rather slightly narrowed behind eyes; occipital carina sharp, from above rather strongly and roundly impressed, but far not reach level of eyes and hind ocelli; hypostomal carina not visible from lateral, meeting with occipital carina before mandible base; length of abscissula 2,5 times lesser than mandible base width; genae short, malar space 1,4 times shorter than the mandible base width; mandibles rather long, parallel-sided at most part, teeth large, lower two times shorter than upper one, situated in the same plane; clypeus flat, separated from middle field of face by slight impression, approximately 2,7 times wider than height, front margin straight with apical wrinkles medially, lateral margins slightly thickened; clypeal foveae small, narrow; labrum not protrude from under clypeus; middle field of face distinctly limited, in middle equal by length to lateral fields; lateral fields swollen; antennal cavities small, deeply impressed, almost reach borders of eyes but far not reach front ocellus level, laterally without tubercles and with distinct interantennal tubercle; ocelli small, slightly convex, diameter of lateral ocellus 1,7 times less than distance from ocellus to eye; ocellar triangle expressed, but slightly elevated. Surface of head and clypeus with large punctures to wrinkled at upper part of middle field, shining; frons on border with antennal cavities wrinkle-punctured with microsculpture; temples with smooth punctures.

T h o r a x: Collar of pronotum long with straight front margin (from above); transverse furrow of pronotum narrow, deep, not interrupted by keel; pronotal ridge not thickened; epomiae sharp; pronotal base gradually curved, almost straight with very sharp apical angle; surface of pronotum wrinkled in lower half and densely punctured in upper one. Mesonotum slightly convex, with equal breadth and width; notauli only just marked at base; surface of mesonotum very densely punctured with microsculpture and slight shine; axillary tongue developed, but weak; subalarum narrow, sharpened at hind half; prepectal carina sharp, far not reach pronotum, considerable part of prepectus visible from lateral; speculum shining, only dorsally with big individual punctures, polished; mesopleural fovea sharp, deeply impressed; mesopleural suture straight, deep, interrupted by strong ribs; mesopleurae without distinct bend; sternauli not developed, only just visible as slight impressions at base; longitudinal groove of mesosternum limited from behind by high carina; scutellum flat, evenly slanted to postscutellum, not carinated laterally, horizontal surface smooth, shining, superficially wrinkly-punctured. Hind margin of metanotum with sharp triangle projections opposite lateral longitudinal carinae. Propodeum from lateral steeply and gradually sloping from base of area superomedia to apex; area superomedia rectangular, elongated, with rounded front margin, from front and behind weakly limited; without costulae; basal area long, convex with distinct lateral carinae; coxal carina sharp; apical transverse carina high elevated; spiracles long, slit-shaped, 2,7 times longer than breadth. First lateral field punctured by big punctures, second lateral field and area spiraculifera roughly wrinkly-punctured to wrinkled; mesopleurae smoothly wrinklypunctured, shining.

L e g s: Strong. Tibiae of front and middle legs with strong spinules. Claws large, long, smooth, sharply, almost at right angle curved almost at middle and slightly widened at base. Hind coxae without scopa.

W i n g s: Areolet pentagonal with very narrow base, practically quadrangular, asymmetrical, external vein of apex longer than internal one; stigma narrow, light; radial cell narrow and long, radius sinuous; nervulus interstitial, strongly curved at apex; ramulus long; veins of both of wings dark; membrane of wing hyaline. Length of front wing 1,7 shorter than body length.

A b d o m e n:Abdomen from above long, fusiform with distinct constriction between 2nd and 3rd tergites, sharply oxypygous; second tergite from above 1,2 times longer than width at apex; sheath of ovipositor protrude behind apex on length of tergite 7. First tergite from lateral with gradual passage to postpetiolus, carinated by lateral carinae and sculpturated between them by sharp transversal ribs; from above petiolus sharply broadened to postpetiolus; distance between spiracles distinctly more than distance from spiracles to hind margin of tergite; middle field of postpetiolus sharply carinated but slightly elevated; its surface delicately longitudinally striated with sparse punctures. Gastrocoeli deeply impressed and slightly oblique; thyridiae slightly expressed, 1,3 times narrower than interval between them; lunulae distinct, in a form of slight impressions of moderate size behind middle of tergite; interspace between gastrocoeli with sharp longitudinal wrinkles, other medial part of second tergite irregularly longitudinallywrinkled, lateral surface of second and third tergites entirely densely punctured, with microsculpture, tergite 4 very densely punctured by superficial punctures, other tergites smooth. Sternites of abdomen with exception of hypopygium unsclerotized.

C o l o r a t i o n: Head and thorax entirely black; head with narrow yellow stripes on internal orbits at level of antennal cavities. Abdomen entirely red with darkened base of first tergite and sheath of ovipositor. Coxae, trochanteres I and most part of femora of all the legs black; trochanteres II, base and apices of femora, tibiae and tarsi reddish-brown, tibiae of middle and hind legs darkened; front tibiae and tarsi partially with yellow pattern.

S i z e: Body length: 11,1-16,2; flagellum: 5,7-6,0; front wing: 9,2-9,6 mm.

M a l e

F l a g e l l u m: Stout, bristle-shaped, with 41-43 segments, with white annulus on segments (9)10-16(17), beyond middle not widened and not flattened ventrally; first segment short, only 1,7 times longer than width at apex from lateral, already segment 5 square; flagellum ribbed dorsally practically from base, with distinct black short-oval tyloides on segments 5-18, black, often reddish ventrally. Flagellum 1,2 times shorter than the front wing and 1,7 times shorter than body length.

H e a d: Head contour from front slightly narrowed downwards, head slightly transversal, 1,2 times wider than height, genae short, 10,7 times shorter than height of an eye; head from above 1,8 times wider than length on external contour. Vertex from lateral gradually slanting down to occipital carina; temples long, 1,2 times longer than longitudinal diameter of an eye at the middle, only just narrowed downwards, from above roundly, rather strongly narrowed behind eyes; occipital carina sharp, from above strongly and roundly impressed, but far not reach level of eyes and hind ocelli; hypostomal carina not visible from lateral, meeting with occipital carina before mandible base; length of abscissula 2,4 times lesser than mandible base width; malar space 4,3 times shorter than the mandible base width; mandibles rather narrow, long, parallel-sided at a most part, teeth large, lower two times shorter than upper one, situated in the same plane; clypeus flat, separated from middle field of face by impression, approximately 2,6 times wider than height, apical surface slightly impressed, front margin with slight prominence in middle; clypeal foveae small, sharp; labrum long, triangle, some narrower than front margin of clypeus; middle field of face high elevated, breadth in middle 1,5 times narrower than lateral fields; antennal cavities small, deeply impressed, almost reach borders of eyes but far not reach front ocellus level, laterally without tubercles and with distinct interantennal tubercle; frons under front ocellus with sharp longitudinal impression; ocelli quite big, distinctly convex, diameter of lateral ocellus 1,4 times less than distance from ocellus to eye; ocellar triangle expressed. Face and clypeus with large, smoothed punctures; frons on border with antennal cavities transversally wrinklypunctured with microsculpture; temples with smooth punctures. Head with long sparse white pubescence.

T h o r a x: Collar of pronotum long with straight front margin (from above); transverse furrow of pronotum narrow, deep, not interrupted by keel; pronotal ridge not thickened; epomiae sharp; pronotal base gradually curved, almost straight. Mesonotum slightly convex, 1,2 times longer than width; notauli only just marked at base; surface of mesonotum very densely sculptured by superficial punctures with shagreen intervals between them and slight shine; axillary tongue developed; subalarum high, narrow, sharpened at hind half; prepectal carina sharp, not reach pronotum, strongly curved backwards so, that considerably part of prepectus visible from lateral; speculum shining, only dorsally with separate big punctures, polished; mesopleural fovea and area around it, deeply impressed; mesopleural suture straight, deep, interrupted by strong ribs; mesopleurae without distinct bend; sternauli not developed; apical margin of mesosternum strongly elevated; scutellum high elevated at base, evenly slanted to postscutellum, not carinated laterally, horizontal surface smooth, shining, superficially densely punctured. Hind margin of metanotum with sharp triangle projections opposite lateral longitudinal carinae. Propodeum from lateral convex, steeply and gradually sloping from base of area superomedia to apex; area superomedia rectangular, elongated, with slightly rounded front margin, from behind more or less distinctly limited; costulae behind middle, more or less distinct; basal area of moderate length, deep, with distinct lateral carinae; coxal carina sharp; carinae of apical part of propodeum high elevated; spiracles long, slit-shaped, 4,5 times longer than breadth. First lateral field and mesopleurae punctured by big punctures, second lateral field and area spiraculifera wrinkly-punctured to wrinkled. Surface of thorax with long white pubescence.

L e g s: Slender, long. Claws large, smooth, sharply, curved at apical third, slightly broadened at base.

W i n g s: Areolet pentagonal with very narrow base, practically quadrangular, symmetrical; stigma rather narrow, dark; radial cell narrow and long, radius sinuous at base and slightly at apex; nervulus interstitial; ramulus long; veins of both of wings dark; membrane of wing hyaline. Length of front wing 1,6 times shorter than body length.

A b d o m e n:Abdomen from above long, fusiform, almost parallel-sided with distinct constrictions between tergites 2-4; second tergite from above with length in middle equal to width at apex. First tergite from lateral with gradual passage to postpetiolus, carinated laterally and sculpturated by sharp transversal ribs; from above petiolus gradually broadened to postpetiolus; distance between spiracles distinctly more than distance from spiracles to hind margin of tergite; middle field of postpetiolus sharply elevated and carinated, wider than lateral fields, its surface sharply longitudinally striated, central part sometimes with impression. Gastrocoeli very deep and slightly oblique; thyridiae only just expressed, practically absent, slightly narrower or equal to interval between them; lunulae only just marked; interspace between gastrocoeli and tergites 2-3 in middle with sharp longitudinal wrinkles weakened to apex, other part of tergites and tergite 4 with very dense puncturation with microsculpture between punctures, tergites 5-6 with superficial puncturation, tergite 7 smooth. Paramerae from lateral narrow, sharpened to apex. Tergites of abdomen with short yellowish pubescence.

C o l o r a t i o n: Head and thorax black with brightly-white pattern; white: margins of clypeus and lateral fields of face, lower margins of frons partially, spots on vertex, mandibles, labrum and maxillary palps, collar and hind corners of pronotum, spots on subalarum and tegulae, scutellum entirely and postscutellum in part. Abdomen with exception of darkened base of first tergite entirely red, always without darkened apex or any parts of tergites. Coxae and femora of all legs predominately black, front femora white inside; tibiae of front and middle legs predominately brightly-white from the outside, hind with white annulus; tarsi of front and middle legs predominantly white, metatarsus of hind tarsi entirely white.

S i z e: Body length: 14,9-15,6; flagellum: 9,3-9,5; front wing: 10,5-11,3 mm.

D i s c u s s i o n: The species is very similar to Coelichneumon haemorrhoidalis (GRAVENHORST) . The main differences are related primarily to the coloration, especially in males. Originally, we considered this species as an expression of intraspecific polymorphism of C. haemorrhoidalis . However, the particularities of morphology of males of C. torsor are obvious enough.

The differential diagnosis of males of Coelichneumon haemorrhoidalis (GRAVENHORST) and C. torsor (THUNBERG)

Coelichneumon haemorrhoidalis C. torsor

1. Flagellum entirely dully-black with tyloides Flagellum ventrally reddish-brown with brightlyof the same color. white annulus and saturated black tyloides.

2. Collar of pronotum without white pattern. Collar of pronotum white.

3. Scutellum black, or at most, with two white Scutellum entirely white, postscutellum with spots on the top; subalarum black. white pattern; subalarum with white spot.

4. Area superomedia from behind not limited Area superomedia from behind distictly limited by carina. by carina.

5. Metatarsus reddish-brown. Metatarsus and base of hind tibiae white.

6. Tergites of abdomen with black pattern, Abdomen with exception of base of 1 st tergite developed in different degree. entirely brightly-red.

7. Paramerae from lateral broad with rounded Paramerae from lateral narrow, narrowed to apex. apex.

E c o l o g y: Both species have one generation per year. Dynamics of theirs seasonal activity is different to some extent. The females and males of Coelichneumon haemorrhoidalis appear in nature somewhat earlier than C. torsor .

The beginning of activity of males of Coelichneumon haemorrhoidalis in ecosystems adjacent to the raised bogs is observed in the first half of May. Their activity is being completed at the end of June – beginning of July. Seasonal activity of males of C. torsor takes shorter period. Males are individually registered only in late May, reaching a sharp peak in the second half of June (71%). Seasonal activity of males ends by middle of July.

Unlike Coelichneumon haemorrhoidalis , females C. torsor appear in nature later, in late June. The peak of their activity is in July. Their activity ends in late July, early August.

Thus, both species are differed not only morphologically, but also by biotopical preference as well as dynamics of the activity.