A new species of Aphidius Nees, 1818 (Hymenoptera, Braconidae, Aphidiinae) attacking Uroleucon aphids (Homoptera, Aphididae) from Iran and Iraq

A new endemic aphid parasitoid species, Aphidius persicus sp. n., parasitic on Uroleucon chondrillae (Nevsky) in Iran and Iraq, is described. The identities of the new species and other co‐existing species of Aphidius are discussed. In the parasitoid association with Uroleucon aphids, A. persicus sp. n. probably replaces Aphidius funebris Mackauer in the studied area. The latter species is a common member of the parasitoid guild on Uroleucon species in the Western Palaearctic and Western Mediterranean.


Introduction
All members of the braconid subfamily Aphidiinae are solitary endoparasitoids of aphids (Mackauer and Starý 1967;Starý 1970). Among them, the genus Aphidius Nees is the largest (with about 70 species worldwide), attacking many aphid genera and species (Pungerl 1986). Two species of Aphidius have been known to attack Uroleucon spp. in the Western Palaearctic: Aphidius funebris Mackauer and Aphidius uroleuci Mescheloff and Rosen (Mescheloff and Rosen 1990;Tomanović et al. 2003b). Aphidius ohioensis Smith is a parasitoid of Uroleucon spp. in the Nearctic (Pike et al. 2000). Aphidius funebris is the only known species from Central Asia parasitic on Uroleucon spp. (Starý 1979;Starý et al. 1998Starý et al. , 2000. A continuous research programme on aphid parasitoids within a broader faunal context and including revisionary taxonomy of individual parasitoid taxa targeting pest aphids in forests, urban agglomerations, cultivated landscapes (fruit trees, crops, and ornamentals), and native ecosystems is being undertaken in Iran.

Material and methods
Specimens were collected during 2003-2005 from different localities in three provinces of Iran and also during 1968-1970 in Iraq. Samples of aphid colonies with or without the mummified individuals were collected from plants in the field and transferred to the laboratory. Plants were herbarium-pressed and identified later. Aphids were killed and preserved in 90% ethanol and 75% lactic acid in a ratio of 2:1 (Eastop and van Emden 1972) for identification at a later date. Other samples were maintained alive in the laboratory at room temperature for 1-2 weeks in mesh-covered semi-transparent plastic rearing boxes. Emerged parasitoids were dissected and slide-mounted either in Canada balsam or Hoyers medium. The external morphology of the parasitoid was illustrated using an Olympus BH2 phase-contrast microscope with a drawing tube.

Aphidius persicus Rakhshani and Starý
The holotype and two paratypes from each sample are deposited in the collection of the Institute of Zoology, Faculty of Biology, University of Belgrade (Serbia); 10 paratypes are deposited in the collection of P. Starý (Č eské Budějovice); and other paratypes are deposited in Tarbiat Modares University Insect Collection Museum, Tehran, Iran.

Diagnosis
Aphidius persicus sp. n. resembles A. funebris, but is immediately distinguishable from it in having antennae with 16-17 segments instead of 18-19 in A. funebris; F 1 slightly longer than F 2 (Figure 2), whereas in A. funebris F 1 is equal in length or slightly shorter than F 2 ; maxillary palpi with three or four segments instead of four in A. funebris; labial palpi with two segments (Figure 1) instead of three in A. funebris; a higher malar index (0.30-0.40 in A. persicus sp. n. instead of about 0.25 in A. funebris); a different ratio between length of the stigma and that of the distal abscissa of R1 [1.9-2.4 times as long as the distal abscissa of R1 in A. persicus sp. n. (Figure 4) instead of equal in length to R1 in A. funebris]; and a lighter colour of the body than in A. funebris. Aphidius persicus resembles Aphidius uroleuci Mescheloff and Rosen, a congeneric species parasitic on Uroleucon in geographically neighbouring Israel, but is immediately distinguishable from A. uroleuci in having a different flagellomere 1 length-to-width ratio (2.5-3.0 in A. uroleuci, 3.0-3.6 in A. persicus sp. n.); a higher malar index (0.30-0.40 in A. persicus sp. n., 0.25 in A. uroleuci); and a different stigma length-to-width ratio (2.8-3.1 in A. persicus instead of 3.5-4.5 in A. uroleuci).

Description
Female. Head (Figure 1): eyes medium, oval. Malar space 0.30-0.40 times longitudinal eye diameter. Head transverse, tentorial index 0.6-0.7, ocellar triangle obtuse. Face sparsely setose, bare at middle portion, clypeus oval, with 9-13 long setae in two rows. Mandibles bidentate bearing 12-13 setae on outer surface. Maxillary palpi four-segmented or threesegmented. In the case of four-segmented maxillary palpi, the last segment in one palpus bears a trace of two segments or the last segment is very elongate. Labial palpi twosegmented, the second segment rounded at tip, with sparse setae (Figure 1). Antenna 16-17-segmented, filiform, with semi-erect and adpressed setae which are as long as about half the diameter of the segments. Flagellomere 1 (F 1 ) (Figure 2) slender, 3.0-3.6 times as long as wide, 1.14-1.18 times as long as F 2 and 1.45 times as long as preapical segment. F 1 with zero to two placodes, F 2 with four to six placodes.
Mesosoma: mesoscutum ( Figure 3) with rows of sparse setae along their length, notaulices effaced dorsally, but observable from the top. Scutellum with 11-12 dorso-lateral sparse setae. Propodeum ( Figure 5) areolate, with narrow central pentagonal areola (sometimes incomplete), upper and lower areola with three to five setae and two to three setae, respectively, at each side. Transverse carinae divide propodeum into unequal portions, upper 1.35-1.4 times longer than the lower areola. Fore wing (Figure 4): stigma 2.8-3.1 times as long as wide and 1.9-2.4 times as long as distal abscissa of R1. r-rs vein 1.5-2.1 times as long as 3/Rs. Surface hairs 0.32 times as long as marginal hairs.
Metasoma: tergum I (5petiole) (Figure 6), 2.8-3.3 times its width at spiracle with middorsal longitudinal carinae. Anterolateral area with 10-11 costulae and dorso-lateral area of tergum I with 10-12 setae after spiracle (Figure 7). Ovipositor sheath (Figure 8) prominent, elongate, slightly concave dorsally, with three ventral, two to three lateral and two to three dorsal setae. Length of ovipositor sheath twice its maximum width and three times at the tip. Second valvulae with a linear dorsal outline.
Colour: general colour of body reddish yellow. Eyes and ocelli black, area surrounding the ocelli with grey patches. Dorsal part of scape and pedicel brown with yellow patches at tips. Annellus yellow. F 1 yellow at base, following flagellomeres brown. Mouthparts yellow. Apices of mandibles light brown to black. Mesosoma light brown. Mesoscutum with two lateral patches and a medial dark strip. Propodeum and metanotum dark brown. Ventral part of mesopleuron dark brown. Fore legs light brown, middle and hind legs dark brown on outer surface. Wings infumated, venation greyish brown (yellowish in fresh specimens), M+m-cu light-coloured at base (m-cu). Tergum 1 of metasoma yellowish, other terga with dark brown bands after the spiracles. Ovipositor sheath black.
Mummy. Yellow-brown, cornicles, antennae and legs except basal femur and coxa dark brown to black. The emergence hole of the adult parasitoid is situated anteriorly between the cornicles, it is rounded and bears a lid at the lower margin.
In Israel (Mescheloff and Rosen 1988, 1990, 1993, the guild consists of E. niger and P. yomenae. The species B. centaureae has not been recorded in this area so far. Instead of it, two native oligophagous parasitoid species on Uroleucon-Aphidius uroleuci Mescheloff and Rosen and Praon unitum Mescheloff and Rosen-were recorded. The Central Asian area, namely Iraq (Starý and Kaddou 1971;Starý 1979), Pakistan (Starý et al. 1998), and Iran , yields A. funebris, E. niger, and P. yomenae, besides some more broadly oligophagous members (P. volucre). However, A. funebris demands more attention because of the determination of a new Aphidius species (A. persicus sp. n., an oligophagous parasitoid on Uroleucon species) known partially under the name ''A. funebris'' from the area, which is dealt with in the present account. The results of our study indicate that A. funebris is a rare species in Iran. It seems that A. persicus sp. n. has replaced it in many associations.
Aphidius species parasitic on Uroleucon in the Palaearctic are a good example of sympatric speciation by adaptive divergence (Tremblay and Pennacchio 1988) to different Uroleucon hosts in the Middle East. Aphidius funebris is widely distributed in the Palaearctic and is characterized by the following plesiomorphic character states: long distal abscissa 1 (5metacarpus), four maxillary and three labial palps, and short flagellomere 1. On the other hand, A. uroleuci and A. persicus sp. n. share a short metacarpus and a smaller number of maxillary and labial palps (three or four maxillary and two segmented labial palps in both of them) as synapomorhies. The presence of A. persicus sp. n. on Uroleucon species in Iran and Iraq represents an endemic parasitoid guild in the Central Asian area.