Department of Zoology, Ul yanovsk State University, pl. 100-letiya Lenina, 4, RU Ul yanovsk, Russia (

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1 THE LOSS, MODIFICATION AND DEVELOPMENT OF CHARACTERS DURING THE LOSS, MODIFICATION AND DEVELOPMENT OF CHARACTERS DURING THE EVOLUTION OF THE EULOPHIDAE (HYMENOPTERA: CHALCIDOIDEA) Zoya A. YEFREMOVA Department of Zoology, Ul yanovsk State University, pl. 100-letiya Lenina, 4, RU Ul yanovsk, Russia ( Abstract Based on world material, the morphology of the Eulophidae has been studied for the first time. Certain morphological characters confirm their ecological adaptations, lifeway and associations with their hosts. Developments of head and metasoma appendages are frequent because they are very important structure in the evolution of parasitism by eulophids. Moreover, many morphological characters could have taxonomic significance. Key words: Hymenoptera, Eulophidae, morphology, modification, evolution, ecological adaptation Introduction Numerous morphological characters have been analyzed among species and genera within the Eulophidae (Bouček 1988; Hansson 1996; Gibson 1997; Yefremova 1995, 1997, 1997, 2001). Although the morphological variations within desribed species are limited the most reliable morphological distinction between species could be benefitial for taxonomy. The investigators who touched the morphology of eulophids, usually have given only taxonomical aspects. Comparative morphology of eulophids has not been studied. Some morphological characters, such as reduction of structures, fusion and morphological development could be useful for establishing evolutionary scenarious and finding out evolutionary direction of transformation of the head and metasoma appendages. Most of the basic trends of morphology are connected with evolution of the parasitism of the Eulophidae. Materials and Methods The material of Eulophidae used in this study was obtained by using a sweep-net when on fieldwork or by the author and her colleagues by rearing from the species hosts. The specimens were mounted soon after capture or placed in paper envelopes laid in cotton wool. I use the method of slide mounting in balsam as described by Noyes (1982). The specimens examined (n = 350) have been drawn. Besides my own specimens, I have investigated material in ZIN (Zoological Institution of Russian Academy of Science, St. Petersburg), BMNH (The Natural History Museum, London), TMLF (Tiroler Landesmuseum Ferdinandum, Innsbruck). For morphological research I have prepared more than 500 figures by light microscopy and 25 illustrations using scanning electron microscopy.

2 144 ZOYA A. YEFREMOVA Results The following evolutionary modifications have been found in the Eulophidae. Head and its appendages. It has been discovered that the appearance of the frontal fork (composed of the X-shaped frontal grooves that are connected to the ventral scrobes) of the face in the subfamilies Entedoninae and Euderinae is associated with endoparasitism. Species of the subfamily Eulophinae, which are ectoparasitic, never have a frontal fork. Tentorium. The tentorium of eulophids varies in structure and in its anterior, dorsal and posterior arms. The dorsal arms of some eulophids are lost or have moved position to the toruli (Fig. 1). The anterior tentorial arms are well developed and terminate in the anterolateral part of the clypeus, which is known as the tentorial pits (many eulophids lack tentorial pits except Hoplocrepis sp., Semielacher sp., Aulogymnus aceris Foerster, or are sometimes visible only in the male (Chrysocharis alpinis sp. nov. Yefremova 2001). The tentorial pits are situated in the epistomal sulcus of the head capsule. The posterior tentorial arms look like broad tubes. The lower bridge in eulophids looks like a broad sclerotized plate. The upper tentorial bridge has two modifications, viz. it comprises two or four parts (Miotropis) (Fig. 2). Dzhanokmen (1995) has commented on the interruption of the upper bridge in the Pteromalidae, but she did not record how many prominences there are in this group. For po.tnt.a pge p.occ s.p.occ r.tnt.a r.tnt.d car.hst Figure 1 Anterior and dorsal tentorial arms of Elachertus olivaceus Thomson, female (dorsal view) ( 120) (r.tnt.a anterior tentorial arm; r.tnt.d dorsal tentorial arm) Figure 2 Part of structure of tentorium of Miotropis unipuncta Nees, female ( 630) (For foramen; p.occ post-occiput; po.tnt.a upper tento-rial bridge; s.p.occ postoccipital sutu- re; pge postgenae) The labio-maxillary complex is attached to the tentorial pits of the head capsule. I have discovered some modifications in the labio-maxillary complex, viz. a decrease in the number of elements of the labial and maxillary palpi: from 2+4 to 1+2 and to 1+1 (Pediobius sp.). The Eulophidae have only one paraglossa (not paired, as in many Hymenoptera); moreover, the paraglossa is sometimes partly reduced or lacking. The primitive chalcid mandible has three teeth. The Eulophidae have developed in a different direction during its evolution: 1) a decrease in the number of teeth; 2) an increase in the number of Systematic Parasitoid Laboratory

3 THE LOSS, MODIFICATION AND DEVELOPMENT OF CHARACTERS DURING teeth; 3) modification (new shape) of the mandible (Dasyeulophus gelechiae Schauff & LaSalle, Paraolinx lineatifrons Ashmead, Grotiusomyia nigricans Howard); 4) partly, namely rudimentary (Cobarus planus Boucek, Eulophus sp., Hoplocrepis sp.) or a fully reduced mandible (Euplectrus, Aroplectrus, Platyplectrus) (Figs 3-9). Some entedonine species have a 2-toothed teeth mandible (Pediobius sp., Kokandia salsolicola Yefremova). Antenna. The common direction of evolutionary transformation of the antennae is oligomerization, because the antenna has the most numerous equivalent structures such as the segments of the flagellum. Females and males have had different transformations of their antennae. The female antennae are used for the host larva search and, thus have only one function, it is therefore more conservative. More modifications are found in the antennae of the male, as their function involves finding females for copulation. That is why the male antennae have more trichoid and placoid sensillae; the presence of dorsal protuberances or branches on the antenna; developments such as a swollen scape in which there are pores; presence of whorled setae on the funicle; a decrease in the number of anellii and the number of club segments. Two later modifications are also characteristic of the female (Fig. 10) Figures 3 9 Main evolutionary transformations of mandible in the Eulophidae. 3, Eulophus pennicornis Nees; 4, Eulophus larvarum L.; 5, Diglyphus crassineurus Erdös; 6, Cocandia salsolicola Yefremova; 7, Parasecodes longigaster Yefremova & Shroll; 8, Tetrastichus trjapitzini Kostjukov; 9, Pnigalio tridentatus Thomson Figure 10 Evolutionary transformation of male antennae during the evolution of the Eulophidae

4 146 ZOYA A. YEFREMOVA I will not mention in detail the modification of the mesosoma and its appendages (wing and leg). Reduction of the veins of the forewing characterises all subfamilies of Eulophidae (except the Euderinae). I have never seen full reduction of veins in the Eulophidae (except in the genus Xanthellum in which the females have rudimentary wings). Some legs of eulophids have lost one segment in the trochanter, but on the other hand many species of eulophids have an additional long hind spur. More important modifications are found in the male genitalia and the female ovipositor. Structure of male genitalia: phallobase, aedeagus, parameral plate, volsellar plate, digitus. The aedeagus has several modifications: divided into two parts (Dahlbominus fuscipennis (Zetterstedt), Chrysocharis sp., Elachertus sp., Euplectrus bicolor Swederus, Miotropis spp., Dicladocerus sp.); divided only in the distal part (Aulogymnus gallarum L., Diglyphus sp., Pnigalio sp., Sympiesis albiventris Storozheva, Sympiesis abureana Waterston) completely fused (Eulophus smerinthicida Bouček, Euderus sp., Zagrammosoma variegatus Masi, Aprostocetus sp.) The ratio of the length of the aedeagus varies considerably from 2 times (Ratzeburgiola sp., Aprostocetus dubius Waterston, Eulophus ramicornis Fabricius; 2.5 times (Aulogymnus gallarum L., Diglyphus sp., Cirrospilus sp., Zagrammosoma sp., Dahlbominus sp.; 3 times (Sympiesis abureana Waterston). The parameral plate can also be modified. Some parameral plates are short and very broad and are never separated from the phallobase; they have one seta (Zagrammosoma sp., Sympiesis abureana Waterston, Ratzeburgiola incompleta Bouček, Elachertus kopetdagensis Yefremova, Eulophus larvarum L., Chrysocharis sp.), other species have two setae: Eulophus smerinthicida Bouček, Dahlbominus sp., Diglyphus iseae Walker, Perditorulus sp., Sympiesis abureana Waterston), and at last some species have lost the setae, e.g. Cocandia salsolicola Yefremova. In other species the parameral plates are long and very narrow, are separated from the phallobase and have two setae (Tetrastichinae). The digitus has many various modifications: shape, position in relation to the phallobase, number of spines. Most eulophids have the digitus parallel to the phallobase (except Euderus sp., subfamily Euderinae and some species of Entedoninae, Perditorulus (Hansson 1996)). The shape could be like that of a bread glove or triangular. The number of digital spines varies. I have discovered a digitus without spines; this digitus has finger-like appendages Fig. 10). In others, the digitus can have spines numbering from 6-7 (Eulophus sp.), 4 spines (Ratzeburgiola sp.) 2 spines (Diglyphus sp., Diaulinopsis sp., Dahlbominus sp., Cocandia salsolicola Yefremova) to 1 spine (Aprostocetus dubius Waterston). If one finds only one spine, it means that there are also several reduced spines. The presence of many spines is a plesiomorphic state (Figs 11-13). The volsellar plate is, as a rule, reduced in most Eulophinae, but I discovered volsellar plates (Euderus palustris Erdős, Zagrammasoma variegatus Masi, Sympiesis albiventris Storozheva, Chrysocharis alpinus Yefremova sp. nov. (in press) and Elachertus sp.). Hansson (1996) also mentioned the presence of volsellar plates in the Entedoninae. Structure of ovipositor: Gonopophyses VIII comprise a long sharp sclerite with arms at the base. The distal parts of the gonopophyses have numerous teeth (Eulophus sp., one species of Zagrammosoma; these species have a lance-shaped gonopophyses without teeth); gonopophyses Systematic Parasitoid Laboratory

5 THE LOSS, MODIFICATION AND DEVELOPMENT OF CHARACTERS DURING IX is also a long sclerite. The distal part of this structure has a lot of median and lateral teeth, more than in gonopophyses VIII. Moreover, the arms of this gonopophyses have coeloconic sensillae that have been discovered in the following genera: Ratzeburgiola sp., Cirrospilus sp., Elachertus sp., Miotropis sp., Aulogymnus sp., Eulophus sp. (Yefremova 1996). Both gonopophyses have bulbus gonopophysales that contain furcula and musculature to which ligaments are connected. The furcula is a V-shaped sclerite and has a foramen (Ratzeburgiola sp., Cirrospilus sp., Aulogymnus sp., Grotiusomyia nigricans Howard); other genera have separate furcula (Euplectrus sp., Dahlbominus sp., Chrysocharis sp., Pediobius sp.) Figures Modifications of digitus of male genitalia. 11, Elachertus kopetdagensis Yefremova; 12, Ratzeburgiola incompleta Bouček; 13, Aprostocetus dubius Waterston Figures Variation of gonostyle XI ( 630). 14, Ratzeburgiola incompleta Boucek; 15, Cirospillus pictus Nees; 16, Eulophus larvarum L.; 17, Euplectrus bicolor Swederus; 18, Platyplectrus babarabicus Myartseva Gonocoxite VIII is a small triangular sclerite with a rounded margin. The shape of this sclerite changes very rarely (Elachertus with curved sclerite). Gonocoxite IX is a long sclerite with a protuberant dorso-mesal margin and a strong long latero-ventral part. This sclerite has an apodeme and coeloconic sensillae (4 or 5). Some genera have finely reticulate sculpture in the latero-ventral part (Aulogymnus sp., Eulophus sp.). Gonostyle IX or sheath as a rule is sclerotized and has numerous trichoid sensillae except in Eulophus sp., Euplectrus sp., Platyplectrus sp. (Figs 14-18). Some eulophids have coeloconic sensillae on the gonostyle as in Elachertus sp. (Yefremova 1998). Ovipositor sheaths IX of some female eulophids exhibit different modifications (Figs 14-18): gonostyle IX is articulated with the gonocoxite; gonocoxite IX has a sclerotized bridge before joining the gonostyle;

6 148 ZOYA A. YEFREMOVA gonostyle lacks articulation it is fused; gonostyle has a membranous junction with the gonocoxite; gonostyle lost its membranous connection and fusion. Ovipositors are used to puncture hosts that have a dense integument in the smaller species. Morphological research of the eulophid ovipositor has shown that it varies in structure and their junction, depending on its host (Yefremova 1997). Discussion Many morphological structures have lost equivalent numbers of modifications during evolution (labial and maxillary palpi, segments of antennae, some structures in the genitalia such as volsellar plates and setae, trichoid sensillae on gonostyle of ovipositor). Reduction of structures (dorsal tentorial arms of tentorium, mandibular teeth, mandibular glands, reduction of mandible to membranous, reduction veins of forewing to rudimentary wings, spines on digitus of male genitalia). Fusion of structure (valvae of aedeagus, gonostyle and gonocoxite of ovipositor). Morphological development (unusual shape of mandible and of digitus, appearance of antennal protuberances and branches and third apodeme of ovipositor, which supports gonocoxite IX). The lost, reduction and fusion of structures have been more frequent than morphological development during the course of evolution. The loss, reduction and fusion in the structure of the appendages of the head, mesosoma and metasoma, the large tagma as in the head, mesosoma and metasoma that were transformed very slowly during evolution. Parasitic wasps of the family Eulophidae have adapted to parasitism by modifying appendages of the body such as antennae, mandibles, wings, legs and the genitalia of both sexes. Acknowledgements I am very thankful to Prof. Dr. M.A. Kozlov and Prof. Dr. A.F. Emeljanov (Zoological Institution of Russian Academy of Science, Saint-Petersburg) for their valuable help and suggestions during discussions on problems encountered during my research. Dr. J. La Salle, Dr. J. Noyes and Ms. S. Lewis (The Natural History Museum, London, UK), are thanked for access to the collections in 1999 and 2000 and for the loan of specimens. References Gibson, G.A.P. (1997) Morphology and terminology. pp In Gibson, G.A.P., Huber, J.T. & Woolley, J.B. (eds), Annoted Keys to Genera of Nearctic Chalcidoidea (Hymenoptera). National Research Council, Ottawa. Hansson, C.H. (1996) A new genus of Eulophidae (Hymenoptera: Chalcidoidea) with remarkable male genitalia. Systematic Entomology 21: Dzhanokmen, K. (1995) Comparative morphology of Pteromalidae head capsule (Hymenoptera, Chalcidoidea, Pteromalidae). Russian Entomological Journal 3(3/4): Systematic Parasitoid Laboratory

7 THE LOSS, MODIFICATION AND DEVELOPMENT OF CHARACTERS DURING Noyes, J.S. (1982) Collecting and preserving chalcid wasps (Hymenoptera: Chalcidoidea). Journal of Natural History 16: Yefremova, Z.A. (1996) The ovipositor of the Eulophinae (Hymenoptera: Eulophidae), its evolution and taxonomical meaning. Entomologicheskoye Obozreniye 75(4): Yefremova Z.A. (1997) Basic directions of evolutionary modification of the morphological structure in the subfamily Eulophinae. Problems of Entomology in Russia 1: Yefremova, Z.A. (1998) The parasitic wasps of the family Eulophidae (Hymenoptera: Eulophidae of the Palearctic (Morphology, Biology, Taxonomy, Evolution and Phylogeny). Abstracts of Thesis of Doctor of Biol. Sciences. Saint-Petersburg, 47 pp. Yefremova, Z.A. & Erlebach, S. (2001) Chrysocharis alpinus Yefremova sp. nov. (Hymenoptera: Eulophidae) parasiting Phylonorycter emberizaepennella Bouché (Lepidoptera: Gracillariidae). Linzer biologische Beitrage 33/2: