Isocolus tinctorius MELIKA et GHARAEI, 2006

Melika, G. & Gharaei, B., 2006, New Species Of Herb Galling Cynipids (Hymenoptera: Cynipidae: Aylacini) From Iran, Acta Zoologica Academiae Scientiarum Hungaricae 52 (4), pp. 385-399 : 386-392

Isocolus tinctorius MELIKA et GHARAEI , sp. n.

(Figs 1–10)

Description – Female. Head and mesosoma black or dark brown, in some specimens pronotum, mesopleuron much lighter, metasoma light brown to reddish; antenna light brown; legs brown to light brown, except dark brown to black coxae. Head black, with dark brown clypeus and mandibles, with few short white setae frontally and laterally, with more densely pubescent postgena and postocciput. Head 1.9 times as broad as long from above, 1.3 times as broad as high in front view (Fig. 1), slightly broader than mesosoma. POD only 1.1 times as long as OOD; LOD 0.5 times as long as POD, 0.5 times as long as OOD and 2.7 times as long as diameter of frontal ocellus; frons with small depressed area under frontal ocellus (Fig. 2). Vertex, interocellar area, frons and occiput delicately coriaceous, vertex rounded, without occipital carina; transfacial distance 1.2 times as long as height of eye, 1.5 times as long as height of lower face (distance between antennal socket and ventral margin of clypeus); distance between antennal rims 0.4 times as long as distance between antennal rim and inner margin of eye and 0.3 times as long as diameter of antennal socket (Fig. 1). Gena finely uniformly coriaceous, not broadened behind eye, nearly 2.0 times as short as diameter of eye, measuring along transfacial line; malar space without sulcus, 0.6 times as long as height of eye; anterior tentorial pit shallow, epistomal sulcus slightly impressed, distinct; central part of lower face slightly elevated, coriaceous. Malar space and lower face, except median elevated area, with strong striae radiating from clypeus and reaching inner margins of eyes and extending into the area between eye and antennal socket (Fig. 1). Postgena finely coriaceous; postocciput impressed, finely coriaceous; posterior tentorial pits deep. Antenna light brown, except dark brown do black scapus, 13-segmented, F4 the longest flagellomere, ratio of scape, pedicel and subsequent flagellomeres follows: 1.0:0.73:1.0:1.13:1.26:1.33:1.0:1.0:1.0:0.86:0.8:0.8:1.7 (Fig. 3). Mesosoma 1.2 times as long as high. Pronotum dark brown, uniformly delicately coriaceous, very densely pubescent laterally along anterior edge, less pubescent laterally and dorsally, dorso-medially long, 2.5 times as short as greatest length on outer lateral margin. Submedian pronotal pit narrow, transverse, separated by a slightly impressed median carina; pronotal plate dark brown to black, with very few short white setae, well-delimited in anterior half, as broad as long (Fig. 5). Propleuron black to dark brown, coriaceous, with transverse delicate striae. Scutum 1.2 times as broad as long in dorsal view; notauli complete, reaching pronotum, smooth and shining, broadened posteriorly; anterior parallel lines distinct, smooth, shining, extending to 1/3 of scutum length; parapsidal lines indistinct, smooth, shining and narrow, extending to half length of scutum; median mesoscutal line absent ( Fig. 6 ); internotauli area and area between parapsidal line and notaulus transversely minutely sculptured, area lateral to parapsidal line longitudinally very finely striate; entire scutum with uniform short white setae ( Fig. 6 ). Scutellum with parallel sides, nearly as broad as long in dorsal view, slightly overhanging metanotum; dark brown disk of scutellum in anteromedian narrowed part, coriaceous, with mainly transverse striae; posteromedially and laterally dull rugose, with few short white setae; slightly impressed posteromedially. Scutellar foveae black, large, smooth and mat, separated by central carina ( Fig. 6 ). Dorso-axillar area with longitudinal parallel fine striae ( Fig. 6 ). Mesopleuron dark brown, turn black ventrally, uniformly finely transversely striate; acetabular carina anteroventrally delimiting a broad area on mesopeluron. Forewing margin with short cilia, veins light brown; areolet small, triangular, well-delimited by veins, Rs and R1 not reaching wing margin; radial cell 2.5 times as long as broad, Cu1b curved strongly outwards wing margin ( Fig. 7 ). Legs light brown, except dark brown or partially black coxae, tarsi lighter, tarsal claws simple, without basal lobe. Propodeum dark brown, finely coriaceous, with uniform dense white setae laterally from black, narrow central propodeal area, delimited by subparallel lateral propodeal carinae which in anterior half 3.0 times thicker and higher than in posterior half, central propodeal area without setae, with irregular wrinkles; propodeal spiracle transverse, with strong raised carina along anterior border. Dorsellum dull rugose, impressed, merged with ventral impressed area; metanotal trough coriaceous, with sparse short white setae ( Fig. 8 ); metapleural sulcus reaching mesopleuron in upper 1/3 of its height; axillula finely coriaceous, with dense white setae hidding the sculpture; nucha black with strong longitudinal paralell ridges ( Fig. 8 ). Metasoma light brown to reddish, metasomal tergite 2 with small antero-lateral patch of white short setae, smooth, with indistinct punctures in posterior 1/3; subsequent tergites and hypopygium uniformly finely densely punctate; prominent part of ventral spine of hypopygium very short with very few short white setae ( Fig. 9 ). Body length 3.0– 3.5 mm.

Male differs in 14-segmented antenna, with F1 very slightly curved, ratio of scapus, pedicel and subsequent 12 flagellomeres follows: 1.0:0.47:1.0:1.2:1.29:1.23:1.11:1.0:1.0:0.94:0.94:0.88:0.88:1.53 (Fig. 4).

Type material — Holotype female: “ Iran, Ilam Province, Shirvan Chardavol city. 2003.V.31. Leg. Babak Gharaei”, “ex gall in flowerhead of Carthamus tinctorius ”, 8 female and 8 male paratypes with the same label as the holotype.

Holotype, 1 female and 1 male paratypes in the Hungarian Natural History Museum ( HNHM), Budapest, Hungary, 5 female and 5 male paratypes in the cynipid collection of Systematic Parasitoid Laboratory, Plant Protection and Soil Conservation Service of County Vas ( SPL), Kőszeg, Hungary; 2 female and 2 male paratypes in the Museo Nacional de Ciencias Naturales , Madrid, Spain.

Etymology — The species is named after the scientific name of the host plant, Carthamus tinctorius L. ( Asteraceae ), which on the species induces flowerhead galls.

Diagnosis — Isocolus tinctorius , sp. n. belongs to the group of species with the mesoscutum finely transversely sculptured (usually transverse striae are delicate, thin and dense). Most closely related to Isocolus carthami DIAKONTSCHUK, 2003 described from Ukraine, Crimea, from flower heads of Carthamus lanatus L. ( DIAKONTSCHUK 2003). In I. carthami the lower face with dense, white, very short piliferous setae (points), which hide the very minute radiating striae; the pronotum and scutellum are black; the median mesoscutal line visible in the posterior 1/3; scutellar foveae are distinctly delimited all around, deep and narrower, smooth and shining; the disk of the scutellum behind the scutellar foveae finely coriaceous as the entire disk; metasomal tergite 2 without antero-lateral patch of white setae, smooth, without punctures in posterior 1/3. In I. tinctorius , sp. n. the lower face

Figs 1–5. Isocolus tinctorius , sp. n. – 1–2 = head: 1 = front view, 2 = dorsal view. 3–4 = antenna: 3 = female, 4 = male. 5 = pronotum, dorsal view.

with much less dense piliferous white setae (points), radiating striae are stronger, distinct, not hidden by white piliferous points; the pronotum and scutellum are dark brown; the median mesoscutal line absent; scutellar foveae indistinctly delimited posteriorly, deep and large, longer than broad, smooth, mat; the disk of the scutellum between scutellar foveae finely coriaceous, while behind foveae is dull rugose; metasomal tergite 2 with small antero-lateral patch of white sparse short setae, smooth, with indistinct punctures in posterior 1/3.

Isocolus tinctorius , sp. n. also closely resembles three other species: Isocolus centaureae , I. scabiosae , and I. serratulae .

In Isocolus scabiosae (GIRAUD, 1859) metasomal tergite 3 with punctures in the posterior 1/3; the transfacial distance 1.6 times as long as height of the eye; the mesoscutum with strong transverse striae posteriorly, the median mesoscutal line distinct in posterior half; the radial cell of the forewing is about 3.0 times as long as broad; induces stem and flowerhead galls on Centaurea species. In I. tinctorius , sp. n. metasomal tergite 3 entirely uniformly densely punctate ( Fig. 9 ); the transfacial distance only 1.2 times as long as height of the compound eye (Fig. 1); the mesoscutum is uniformly delicately transversely striate, the median mesoscutal line absent ( Fig. 6 ); the radial cell of the forewing only 2.5 times as long as broad ( Fig. 7 ).

In Isocolus serratulae (MAYR, 1882) the median mesoscutal line extending at most to 1/5 of the mesoscutum length; the scutellum reticulate-coriaceous; metasomal tergite 3 with punctures only in the posterior 1/3; the transfacial distance around 1.5 times as long as the height of the compound eye; F1 of the female antenna is clearly shorter than F2; cilia on the forewing margin is very indistinct; induces galls on Serratula species. In I. tinctorius , sp. n. the median mesoscutal line absent; the scutellum dull rugose ( Fig. 6 ); the transfacial distance only 1.2 times as long as height of the compound eye; F1 nearly equal F2 (Fig. 3); cilia on the forewing margin is short but distinct ( Fig. 7 ).

Isocolus centaureae DIAKONTSCHUK, 1982 resembles I. tinctorius , sp. n. in its entire habitus, minutely transversely sculptured mesoscutum, absence of the median mesoscutal line, metasomal tergite 2 smooth, without punctures, while subsequent tergites are uniformly and densely micropunctate. However, differs in 12-segmented antennae in the female, submedian pronotal pits are separated by a distinct elevated broad carina; the head is rounded in front view, the lower face with very delicate radiating striae, the acetabular carina on the mesopleuron delimiting a very narrow area; scutellar foveae are smaller, with transverse rugae on the bottom; lateral propodeal carinae subparallel, uniformly broad; induces flowerhead galls in Centaurea diffusa Lam. and C. squarrosa (Boiss.) ( DIAKONTSCHUK 1982) . In I. tinctorius , sp. n. the female antenna 13-segmented; submedian pronotal pits are indistinctly separated by an impressed very narrow area; the lower face with strong radiating striae, partially present on the median elevated area (Fig. 1); scutellar foveae are larger, with smooth mat bottom ( Fig. 6 ); lateral propodeal carinae narrow in posterior half and around 3.0 times broader in the anterior half ( Fig. 8 ).

Gall structure and location – Galls are scattered at the base of the flower head of Carthamus tinctorius ( Fig. 10a , arrowed). Two types of galls’ location were found. Few galls are forming in the ovary, which is deformatted, after the larva hatched from the egg and gradually modifying it into a cylindrical whitish gall, with thick wall and rounded tip and afterwards the growing of the ovary is stopped. As the larva growth, the width of the gall increasing and becaming nearly similar to a healthy seed. The gall, when mature becoming dark brown to blackish ( Fig. 10b ). This type of the gall is very rare. Majority of galls are on brackts ( Figs 10 c-d). Each flower head contain only one gall, very rarely two. Each brackt has only one gall. The location of galls on brackts vary – from the base to the tip, but more frequently they are forming on the upper part of brackts. Galls at the base of brackts are elongated, elliptical, green when young, with very hard and smooth wall, 3.0–6.0 mm in length and 1.2–1.9 mm in diameter. After maturing, similarly to the flower head, they are becoming yellow. Galls on free parts of brackts are rounded, spherical, 1.0–2.0 mm in diameter, or somewhat elongated (2.1–3.5 mm long and 1.5–2.0 mm in diameter), green, with smooth, very hard and thick wall.

Biology – The sexual generation is known to induce galls in the flowerheads of Carthamus tinctorius L. ( Asteraceae ). Adult wasps emerge in late May–June.

Comments – BELIZIN (1959) redescribed an aylacine wasp, Phanacis carthami GUSSAKOVSKY, 1933 , collected in Uzbekistan and known to induce root galls on Carthamus tinctorius . On the basis of the redescription, given by BELIZIN (1959), it is a good Phanacis species. Recently, this species was found in Ukraine, Crimea and was reared from stem galls on Carthamus lanatus L. ( DIAKONTSCHUK 2003). So, taken into account the recently described I. carthami , Isocolus tinctorius , sp. n. is the third known cynipid gallwasp species associated with Carthamus spp.

Distribution – Currently known from Iran, Ilam Province. Probably, distributed in Iraq as well

ABDUL-RASSOUL (1980).

Natural enemies – Isocolus tinctorius , sp. n. is a minor pest of Carthamus tinctorius and have no economic importance in Ilam province in the present time. Three species of parasitoids were reared from the galls: Sycophila submutica (THOMSON, 1876) ( Eurytomidae ), O rmyrus gratiosus (FÖRSTER, 1860) ( Ormyridae ), and Adontomerus crassipes (BOUČEK, 1982) ( Torymidae ). Ormyrus gratiosus has been distributed in all parts of the province and appeared to be a more frequent parasitoid than two others. Sycophila submutica and A. crassipes , were found only in the southern part of Ilam province and nearly 1% of gall wasp larvae were parasitized by them.

Sycophila submutica is a widespread Western Palaearctic species, known as a parasitoid in galls of aylacine wasps. MAYR (1905) and CLARIDGE (1959) mentioned that this Sycophila species trophically associated with those aylacine wasps, which induce galls on Asteraceae only, what is supported by NIEVES-ALDREY (2001), who reared this species only from Aulacidea hieracii (BOUCHÉ, 1834) , Isocolus lichtensteini (MAYR, 1882) , I. scabiosae (GIRAUD, 1859) , and Phanacis centaureae FÖRSTER, 1860 . ZEROVA (1995) mentioned also Liposthenes glechomae (LINNAEUS, 1758) (galls on Glechoma hederaceae L., Lamiaceae ) and Aulacidea ascanica DIAKONTSCHUK, 1984 (galls on Serratula xeranthemoides M. B., Asteraceae ) in between S. submutica hosts.

ABDUL-RASSOUL (1980) described a new eurytomid parasitoid species, Sycophila emarginata , reared from galls of an undescribed species of Isocolus in the flower heads of Carthamus oxyacanthus M. Bieb. collected in Iraq in 1977–1979.

Ormyrus gratiosus earlier was cited as a parasitoid of Isocolus scabiosae only ( NOYES 1998), while Adontomerus crassipes was reared from galls of I. lichtensteini and was known from Algeria and Spain only ( NOYES 1998, NIEVES- ALDREY 2001).

Figures

Figs 6–9. Isocolus tinctorius, sp. n.: 6 = scutum and scutellum, dorsal view. 7 = forewing. 8 = propodeum and metanotum, dorsal view. 9 = metasoma of female, lateral view

Fig. 10. Isocolus tinctorius, sp. n., gall: a = galls (arrowed) in the flower head of Carthamus tinctorius, b = mature gall cell, c,d = galls on bracts