A CONTRIBUTION TO THE ENCARSIA AND ERETMOCERUS ( HYMENOPTERA : APHELINIDAE ) SPECIES FROM THE ARASBARAN BIOSPHERE RESERVE AND VICINITY , NORTHWESTERN IRAN

The fauna of the Encarsia and Eretmocerus species (Hymenoptera: Chalcidoidea: Aphelinidae) from Arasbaran and its vicinity (Northwestern Iran) is studied in this paper. A total of 16 Encarsia species, including E. acaudaleyrodis Hayat, E. aleurochitonis (Mercet), E. aurantii (Howard), E. azimi Hayat, E. berlesei (Howard), E. citrina (Craw), E. elegans (Masi), E. elongata (Dozier), E. fasciata (Malenotti), E. formosa Gahan, E. inaron (Walker), E. lounsburyi (Berlese and Paoli), E. lutea (Masi), E. luteola Howard, E. mineoi Viggiani, E. perniciosi (Tower), and 4 Eretmocerus species (Eretmocerus cadabae Viggiani, Eretmocerus mundus Mercet, Eretmocerus nikolskajae Myartseva, Eretmocerus serius Silvestre) were collected.


INTRODUCTION
The genus Encarsia Foerster (Chalcidoidea: Aphelinidae) contains a diverse and cosmopolitan group of species that are usually parasitic on Aleyrodidae (whiteflies), Diaspididae (armored scales), Aphidoidea (aphids) or themselves (as autoparasitoids).A few species are parasitoids of the eggs of Lepidoptera (Polaszek, 1991;Huang and Polaszek, 1998).The genus Encarsia represents one of the most important parasitic groups used in biological control, and various species are currently being collected as part of intensive foreign exploration efforts to search for parasites of whiteflies of the genus Bemisia (Heraty and Polaszek, 2000).Eretmocerus Haldeman species are solitary, primary parasites.Eggs are deposited under the venter of whitefly larvae.The egg hatches from beneath the whitefly and the wasp larva enters the hosts through an incision made in the venter of the whitefly.Eretmocerus species attack many genera of whiteflies in the subfamily Aleyrodinae including various important pest species, and have been used effectively in several biological control programs (Rose and De Bach, 1991-92;Rose and Zolnerowich, 1997;Ghahari, 1999); no Eretmocerus species have yet been reported to attack whiteflies belonging to the subfamily Aleurodicinae.
Arasbaran is an important region in the East Azerbaijan province.This biosphere reserve is situated in the north of Iran at the border with Armenia and Azerbaijan and belongs to the Caucasus Iranian Highlands.In between the Caspian, Caucasus and Mediterranean region, the area has mountains up to 2,200 meters, including high alpine meadows, semi-arid steppes, rangelands and forests, rivers and springs.The location of Arasbaran is 38°40' to 39°08'N; 46°39' to 47°02'E and its elevation (meters above sea level) is +250 to +2,887.

MATERIALS AND METHODS
The study was mainly based on material collected from different part of Arasbaran and its vicinity (Northwestern Iran).Each sample was given a unique code number and the host plant, host whitefly species, date and location were noted.Nymphs of the parasitized hosts were kept in emergence chambers and the parasitoids were transferred to 75% ethanol, where they remained at laboratory temperature until further examination.The whiteflies were identified to species level using the fourth instar pupal case from which the parasitoid had emerged.All the specimens used in this study were slide mounted as described by Noyes (1982) with the following modifications: specimens were placed in 10% KOH for 5-8 min and incubated at 70°C using a block heater.The samplings were conducted in 11 localities from the East Azerbaijan province (Abshahmad, Ahar, Aras boundary, Aynalo, Horand, Jolfa, Kaleybar, Khodafarin, Khomarloo, Maragheh and Tabriz) and 5 localities from the West Azerbaijan province (Khoy, Maco, Ourmieh, Oshnavieh and Piranshahr).In this paper, the classification, nomenclature, host and distributional data and species group of Encarsia and Eretmocerus suggested by Heraty et al. (2007) and Evans (2007) have been followed.

RESULTS
A total of 16 species of Encarsia and 4 species of Eretmocerus were collected from Arasbaran and its vicinity in northwestern Iran.The list of species with hosts and distributional data are given below.

List of Encarsia species
Encarsia acaudaleyrodis Hayat, 1976 Material examined: Comments: E. acaudaleyrodis is very similar to E. mineoi Viggiani, but in the latter species the body is completely yellow except for dark clypeus; flagellar segments longer; middle tibial spur half the length of basitarsus; ovipositor at most slightly longer (1.12 times) than middle tibia, but in E. acaudaleyrodis 1.26 times as long as the mid tibia.The extreme similarity of E. acaudaleyrodis and E. mineoi suggests that these two species are probably sympatric species.Two other species, E. americana (De Bach and Rose) and E. basicincta Gahan, are also close to E. acaudaleyrodis, but the morphological differences of these species have been given by Hayat (1998).

Species group: inaron-group.
Comments: E. azimi is close to E. margariventris (Mercet), but can be distinguished from it by the characteristic sculpture of the mesosoma, longer third valvulae and several characters of the males.E. reticulata Rivney (in Rivney and Gerling, 1987) may be another synonym of E. azimi, but a final opinion is deferred for further study of the types (Hayat, 1998).Unfortunately, the type material of E. reticulata appears to be lost.On the basis of Schmidt et al. (2001) Comment: Aleurolobus olivinus is newly recorded as the host of E. elegans.E. elegans is a widespread species in the old world (Polaszek et al., 1999).Comments: E. inaron is a widespread species and a rather efficient parasitoid for the control of T. vaporariorum in greenhouses and S. phillyreae in nature.E. inaron constitutes a complex of cryptic species, and morphometric and molecular analysis of the E. inaron species-group was studied in detail by Manzari et al. (2002), and a new species was described as E. estrellae Manzari and Polaszek.With the addition of the above synonyms, it appears that E. longicornis Mercet and E. siphonini Silvestri may also constitute synonyms of E. inaron, but further study by advanced taxonomic is necessary to confirm this.Different populations of E. inaron show color differences, and this variety has resulted in ambiguities.Hulden (1986) described E. borealis on the basis of minor color differences from E. aleyrodis.Polaszek et al. (1992) and Laudonia and Viggiani (1995) have discussed color variation in this species.An impressive study was made on the biology of E. inaron in Iran by Ghahari (1999).Host: Diaspididae: Chrysomphalus dictyospermi, Parlatoria ziziphi (Lucas), Carulaspis juniperi (Bouche) (= visci Schrank), Chrysomphalus aonidium (L.) (as C. ficus), Chrysomphalus sp., Cornuaspis (= Lepidosaphes) beckii (Newman), Hemiberlesia sp., Aonidiella aurantii (Huang and Polaszek, 1998), Abgrallaspis (as Aspidiotus) cyanophylii (Signoret), Aspidiotus nerii Bouche (as A. hederae), C. personatus Comstock, Diaspis echinicacti (Bouche), Hemiberlesia lataniae (Signoret) (as Diaspidiotus), Fiorinia fioriniae (Targionii), Lepidosaphes pinnaeformis (Bouche), Lineaspis (as Chionaspis) striata (Newstead), Parlatoria pergandei Comstock, Parlatoria proteus (Curtis).
Comment: E. lounsburyi is very close to E. citrina (Craw).The main difference between the two species is the number of setae on the submarginal vein, one seta in E. lounsburyi but two in E. citrina.Also, the fore wings of E. lounsburyi have a longer marginal fringe than E. citrina, and petiole with fine sculpture.
Encarsia lutea (Masi, 1909) Material examined: West Azerbaijan province: Khoy, 10♀, 2♂, ex Bemisia tabaci Genn.Comments: There exist considerable color variations of E. lutea as two or more species may be involved, but further studies are required to either confirm or refute this.Different populations of E. lutea from Australia and the Pacific Islands differ from each other by a single point mutation in the D2 expansion region of the 28S ribosomal DNA gene region (Babcock et al., 2001).Additional coloration, this species shows variation in the dimensions of the antennal segments, and length of the marginal fringe compared to wing width (Hayat, 1998).The male of E. lutea was collected from eggs of Heliothis zea (Boddie) and Trichoplosia ni (Hubner) (Noctuidae) in Piranshahr (West Azerbaijan province).E. lutea is the most important parasitoid on B. tabaci in the cotton fields of the Middle East (Gerling, 1986).Comments: Certain populations of E. luteola are extremely difficult to distinguish from E. formosa because both the species belong to the E. luteola group and their morphological differences are very slight.The most morphological differences between the two parasitoids are as below.In E. luteola, each axilla typically with at most 5 reticulate cells longitudinally; F2 of female without a sensillum; mid tibial spur about half the length of the corresponding basitarsus, face mostly pale.In E. formosa, each axilla typically with at 6 (usually more) reticulate cells longitudinally; F2 of female with a sensillum; mid tibial spur less than half the length of the corresponding basitarsus; face almost entirely dark.

Encarsia luteola
E. luteola was introduced into Israel from California for the control of B. tabaci (Rivnay and Gerling, 1987).This species also was introduced into Russia, Uzbekistan and many other adjacent regions for the biological control of B. tabaci on cotton, vegetables and decorative plants in 1989(Tryapitzin et al., 1996)).With due attention to the nearness of Israel, Russia, and the Federation of Independent States, the introduction of the parasitoid into Iran is probably through these countries.Comments: E. mineoi is close to E. acaudaleyrodes and perhaps these species are conspecific (Polaszek et al., 1999).The most reliable difference is the ovipositor length, which is, in E. mineoi, shorter than, or up to 1.1 times the length of the middle tibia, and in E. acaudaleyrodes 1.2 times as long as the middle tibia.There are many materials of E. menoi, E. meneoi and E. moneoi in Israel; with due attention to their same host (Acaudaleyrodes citri), it is possible that all of them are E. acaudaleyrodis.Re-examination of these materials is necessary for final statement.Males of E. mineoi were reared by Polaszek et al. (1999)  Comments: E. perniciosi is one of the most efficient parasitoids on the San Jose scale in different regions of the world.Our examination of the different populations of this parasitoid indicated that there is variation in the presence/absence of a longitudinal sensillum on F1.The reason of this variation that was seen in the surveys of Huang and Polaszek (1998) can be the effect of different biotypes or races of hosts (armored scales) on the parasitoid or speciation of another Encarsia species.Further studies will be undertaken to solve this problem.Polaszek (erroneously reported in much of the literature as Encarsia opulenta (Silvestri)) and Amitus hesperidum Silvestri which appear to have overdominated Eretmocerus serius.

DISCUSSION
The results of this research indicate that the fauna of Encarsia and Eretmocerus species in Arasbaran is very diverse.Although several samplings were conducted in different regions of Arasbaran and also on various plants, this region is very large area and we expect that some other species rremain to be discovered.Iranian Encarsia and Eretmocerus species were revised by Abd-Rabou and Ghahari (2004) and Abd-Rabou et al. (2005b).These parasitoids have an efficient role in the biological control of whiteflies (Aleyrodidae) and armored scales (Diaspididae) and if conserved, they can have powerful role in the control of these important agricultural pests (Gerling, 1986;Ghahari and Hatami, 2000).