Ctenichneumon THOMSON

A. M, 2011, Illustrated key to the genera of the subtribe Amblytelina of Palaearctic (Hymenoptera, Ichneumonidae, Ichneumoninae, Ichneumonini), Linzer biologische Beiträge 43 (1), pp. 597-711 : 662-664

10. Ctenichneumon THOMSON

Ctenichneumon THOMSON 1894 - Opusc. Entom. 19: 2082.

Type species: Ichneumon funereus Geoffroy.

Ctenichneumon: HEINRICH 1961 - Can. Ent., Suppl. 23: 450-451.

Ctenichneumon: HEINRICH 1965 - Entomol. Ts. Agr. 86: 1-2: 98.

Ctenichneumon: HEINRICH 1977 - Ichn. Florida and Neigb. States 9: 107-108.

Ctenichneumon: RASNITSYN 1981 - Opr. Faun. SSSR 3 (3): 567, 620.

D i s t r i b u t i o n: Holarctic, Oriental (highlands) and Neotropical Regions.

I n t r o d u c t i o n:

Genus is close to Diphyus KRIECHBAUMER (= Pseudamblyteles ASHMEAD), differing from it by practically full absence of thyridia, by sculpture and morphology of anterior tergites of abdomen and by particularities of coloration too. Strongly impressed gastrocoeli with convex, arcuate interval between them and practically fully absent thyridia are characteristic for the genus. Sculpture of second tergite is more coarse than in Diphyus , and anterior tergites are divided by deep in different degree constrictions. In addition, for species of the genus uniform red or black or theirs combination coloration is characteristic. An important distinctive character of the genus is morphology of males’ flagellum. In contrast to other genera of Ichneumonini , flagellum of males is ribbed ventrally practically from base. This character is determinative under determination of ambiguous generic belonging of species. Hypopygium of males is extended in different degree to rounded or rarely cut (e.g. edictorius L.) apex, without long process.

The species of genus remind somewhat Protichneumonini (Coelichneumon) . There are uniformly convex profile of propodeum with external carina of area dentipara practically parallel to metapleural carina, strongly impressed gastrocoeli of both of sexes.

M o r p h o l o g y:

F l a g e l l u m: Bristle-shaped, slender, strongly attenuated and pointed toward apex, behind middle only just widened and of females only just visible flattened. Flagellum of males ribbed ventrally practically from base (with transversal ribs or elevations in middle, or closer to apex of segments) with short bristles on top and with distinct narrow tyloides.

H e a d: Head contour from front uniformly but not sharply narrowed downwards;

temples from above rather strongly roundly narrowed behind eyes; mandibles narrow, upper tooth sharp, longer than lower one.

T h o r a x: Mesonotum from slightly to strongly convex, only just longer than width; axillary tongue expressed; scutellum high elevated above postscutellum and roundly fall backwards, laterally not carinated, in males more high elevated. Hind margin of metanotum with projections. Propodeum from lateral angle-shaped; with high elevated horizontal part which approximately equal by length to length of area posteromedia in middle, convex in profile; area superomedia rectangular, square, or slightly transverse, without costula; coxal carina developed; area dentipara at apex without tooth, with external carina almost parallel to carina metapleuralis, or even almost approaching with it to apex ( C. nitens CHRIST ).

L e g s: Slender to moderately stout. Hind coxae of females without scopa.

W i n g s: Areolet big, pentagonal with wide base; membrane of wing hyaline.

A b d o m e n Of females amblypygous. Middle field of postpetiolus longitudinally striated, distinctly elevated and carinated. Gastrocoeli distinctly and deeply impressed, thyridia absent or only just marked; anterior tergites distinctly punctured, second tergite medially longitudinally striated; 2-4th tergites sharply divided by constrictions. Sternites strongly sclerotized in comparison with other genera, or without fold (type species), or with fold on 2-3rd sternites. Hypopygium of males extended to rounded or rarely cut apex, without long process.

C o l o r a t i o n: Body of European species black, red or both color in combination. White spots on abdomen are registered in some oriental species.

S i z e: Palaearctic species 10-18 mm.

B i o l o g y a n d e c o l o g y:

H o s t s: From the literature, for eight species of a genus the following data about hosts are known: C. castigator (F.) – Biston betularia L. ( Geometridae ), Apamea anceps DEN. ET SCHIFF. , Archanara sparganii ESP., Cirrhia togata Esp., Cucullia absinthii L., Gortyna flavago DEN. ET SCHIFF. , Hadena perplexa DEN. ET SCHIFF. , Mamestra oleracea L., Orthosia stabilis DEN. ET SCHIFF. (Noctuidae) ; C. divisorius (GRAV.) – Mamestra serena SCHIFF., Polia tincta BRAHM , Pyrrhia umbra HUFN. (Noctuidae) ; C. funereus (GEOFFROY) – Smerinthus ocellatus L. ( Sphingidae ); C. divisorius (GRAV.) – Apamea anceps DEN. ET SCHIFF. (Noctuidae) ; C. melanocastanus (GRAV.) – Panolis flammea DEN. ET SCHIFF. (Noctuidae) , Vanessa antiopa L. ( Nymphalidae ); C. nitens (CHRIST) – Trichiura crataegi L. ( Lasiocampidae ), Caradrina clavipalpis SCOP., Mamestra serena SCHIFF. ( Noctuidae ); C. panzeri (WESM.) – Agrotis exclamationis L., A. segetum DEN. ET SCHIFF., A. ypsilon ROTT., Helicoverpa armigera HBN. , Spodoptera exigua HBN. (Noctuidae) ; C. repentinus (GRAV.) – Zerinthia polyxena DEN. ET SCHIFF. ( Papilionidae ), Cucullia chamomillae DEN. ET SCHIFF. , Hadena rivularis F., Orthosia munda SCHIFF. (Noctuidae) ( HERTING 1976; RASNITSYN 1981).

S p e c i e s c o m p o s i t i o n a n d a b u n d a n c e: The genus is presented in region of researches by seven not numerous species. Abundance of this genus in the nature (quantity of the collected individuals / quantity of revealed species of a genus) leads it to the 7th place according to indicator of abundance among Amblytelina and on only 44th place among genera of Ichneumoninae St. in the region (12 individuals / 1 species of genus). According to abundance in collections in decreasing order they are distributed as follows: C. repentinus (GRAV.) – 36 %, C. funereus (GEOFFROY) – 23 %, C. castigator (F.) – 18 %, C. divisorius (GRAV.) –11 %, C. inspector (WESM.) – 7 %, C. edictorius (L.), C. nitens (CHRIST) .

B i o t o p i c a l d i s t r i b u t i o n: The genusis presented in the majority of the open and forest ecosystems. 61,5 % from total number of collected specimens are focused on open ecosystems (meadows and personal plots) (4 species) and 38,5 % on forest ones. Most mass species, C. repentinus is presented in the greatest quantity in the open ecosystems. Meadows communities and personal plots are being prefered also by C. castigator and C. funereus . Among forest ecosystems, species of the genus are presented in the greatest quantity in the pine forests (23 % and 6 species), first of all C. divisorius – in polytric pine forests (Pinetum pleurozosum).

S e a s o n a l a c t i v i t y a n d h i b e r n a t i o n: Representatives of the genus are being met in the nature from the end of April till October. Low abundance of representatives of a genus does not allow with sufficient confidence to estimate number of generations of separate species. The most mass species C. repentinus has the short period of activity from June till August, and, males appear in the nature first. C. funereus and C. inspector have two short periods of activity with interval of one month. G. HEINRICH (1961) indicates about of presence of two generations during a season in C. edictorius (L.). In our collectings this species was being met sporadically in July-August.

G. HEINRICH (1961) indicates that females of the genus do not hibernate. We also did not find hibernating females of representatives of the genus, despite of many years of efforts. In indirect acknowledgement of such process of development of species of the genus is also the fact of presence in our disposal the male of C. castigator (F.) which obviously has received as a result of breeding, with a label " Minsk, Pukhovichi, 01.04.193 0, N. Dobrotvorsky" as well as the last date of a finding of females Ctenichneumon in the nature is being 1st decade of September.

At the same time, in the literature there are the data generalized by A. RASNITSYN (1964), about a finding of hibernating females of C. funereus (GEOFF.) , C. inspector (WESM.) , C. melanocastaneus (GRAV.), C. repentinus (GRAV.) and C. nitens (CHRIST.) . Under our data, the females of two species С. funereus and C. divisorius begin activity in the nature by the first, and males appear only in second half of summer.