389 Helminths of the sand lizard, Lacerta agilis (Reptilia, Lacertidae), in the Palaearctic : faunal diversity and spatial patterns of variation in the composition and structure of component communities V.P.SHARPILO , V.BISERKOV , A.KOSTADINOVA , J. M. BEHNKE * and Y.I.KUZMIN Department of Parasitology, I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 15 Bogdan Khmelnitsky Street, Kiev-30 MSP 01601, Ukraine Department of Biodiversity, Central Laboratory of General Ecology, Bulgarian Academy of Sciences, 2 Gagarin Street, 1113 Sofia, Bulgaria School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD (Received 14 March 2001 ; accepted 8 April 2001) We studied variation in the structure of component communities of helminths in sand lizards, Lacerta agilis, from 30 localities in the Ukraine and Bulgaria. Thirty-five separate samples of lizards, with a total of 661 completely censused infracommunities, yielded 30 helminth species (4 cestodes, 10 trematodes, 3 acanthocephalans and 13 nematodes). In its range within the Ukraine, L. agilis serves as the final host for 13 species of which only 3 (S. lacertae, S. hoffmanni and P. molini) can be considered as lizard specialists. A characteristic feature of these helminth component communities was the large proportion of heteroxeneous helminth species for which L. agilis serves as paratenic host. Sand lizards in the meadow steppeland zone were primarily parasitized by larval helminths that represented a major proportion of the total number of all worms recovered while those sampled in the grasslandforest transition zone were characterized by substantially higher proportions of adult helminths using lizards as final hosts. However, L. agilis was parasitized by a much higher proportion of lizard specialists in the ‘typical ’ habitats of the meadow steppeland zone as opposed to those located in ‘marginal ’ habitats in the grasslandforest transition zone, where helminths were shared to a greater extent with amphibian hosts. Key words : sand lizard, Lacerta agilis, helminth fauna, nematodes, cestodes, trematodes, helminth communities, regional variation, Ukraine, Bulgaria. The community ecology of parasites of vertebrates is a subject that has attracted considerable interest in the last decade, resulting in the development of a conceptual framework for the hierarchical structure of parasite communities (Poulin, 1998 a). This has enabled hypotheses to be formulated about the key processes that regulate the composition and structure of parasite component communities (Esch, Bush & Aho, 1990). Although fish, birds and mammals have been widely studied in this context, relatively little information is available on the characteristics of helminth communities in reptiles, especially with regard to quantitative data based on completely censused infracommunities (Aho, 1990 ; Bush, 1990). * Corresponding author : School of Life and Environ- mental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD. Tel : 0115 951 3208. Fax: 0115 951 3251. E-mail : jerzy.behnke nottingham.ac.uk Moreover, the structure of helminth communities in reptiles from the Palaearctic region has received little attention at both hierarchical levels of organization, the infracommunity and the component community. One of the most abundant and widespread reptile species in Eurasia is the sand lizard, L. agilis, its distribution being primarily attributable to its tol- erance of diverse environments ranging from the steppe through agricultural fields to woodland habitats (Yablokov, Baranov & Rozanov, 1981 ; Frazer, 1989). Nevertheless, as with most reptile species, the movement of individuals is thought to be confined to a considerably more limited range since, being territorial animals, sand lizard individuals or pairs occupy, mark and defend a limited area within the habitat (Lewin, 1992). The helminth fauna of L. agilis has been described throughout its range in Europe, and is reported to be the richest among the Palaearctic lacertids (Sharpilo, 1976). The wide- spread distribution of sand lizards, and the available wealth of information on their biology, ecology and parasite fauna, make this species a particularly useful Parasitology (2001), 123, 389–400. 2001 Cambridge University Press DOI : 10.1017S0031182001008587 Printed in the United Kingdom