Genetic differentiation between two species of the medicinal leech, Hirudo medicinalis and the neglected H. verbana, based on random-amplified polymorphic DNA

Abstract

The medicinal leech is one of the few parasitic invertebrates widely used in medicine and as a scientific model object. Because of a dramatic decline in its natural populations, it is subject to considerable conservation effort. Despite all attention, there is confusion regarding the taxonomic status of different morphological forms. The prevailing view is that all varieties of medicinal leech in Europe represent the same species, Hirudo medicinalis. However, the present study based on RAPD molecular markers demonstrates that a second European taxon, H. verbana, forms a distinct species. Phenetic clustering and principal coordinate analysis of eight populations revealed the same basic structure, reflecting taxonomic rather than geographic subdivision. Variation between species explained 60% of the total molecular variance (phiCT=0.60, P<0.001). Both taxa displayed a significant number of specific RAPD markers. Conversely, no specific fragment supporting the geographic association of both taxa was found. Since the stronghold of commercially exploited medicinal leech populations in southeastern Europe and Turkey belongs to H. verbana, most medicinal and scientific applications probably use this species, not H. medicinalis. Appropriate taxonomic correction of international conservation conventions and legislation is essential.

Hirudinea (Annelida) species and their ecological preferences in some running waters and lakes

“…Furthermore, there is not any legal protection for H. verbana in countries where they inhabit naturally (Elliot and Kutschera 2011). Although the conservation status still continues for H. medicinalis after they were separated from each other, any protective legislation has not been established for H. verbana (Trontelj et al 2004). Ecological information about H. medicinalis and its closely-related species H. verbana in the wild is limited.…”

“…The decline in suitable hosts in natural habitats threatens the population of these species. Number of small wetlands and shallow ponds has declined like the other European countries (Trontelj et al 2004) and this scarcity affects the organisms which live naturally in these habitats. To conserve these species, knowledge about their natural habitats and ecological preferences of species is very important (Elliot and Kutschera 2011).…”

The first recorded occurrence of Hirudo verbana Carena, 1820 (Hirudinea: Arhynchobdellida: Hirudinidae) in Romania

“…Only in 1999, the species status was re-established for the forgotten H. verbana (Nesemann & Neubert, 1999), which corresponds morphologically to the south-eastern H. medicinalis f. officinalis, yet that view was not generally accepted. By means of the random amplified polymorphic DNA technique and the analysis of nuclear and mitochondrial gene sequences and nuclear microsatellites, H. verbana was proved to be a distinct species from H. medicinalis (Trontelj et al, 2004;DeSalle et al, 2005;Siddall et al, 2007). The two species interbreed in captivity, but some degree of reproductive isolation has been found (Petrauskiené et al, 2009).…”

“…Both H. medicinalis and H. verbana are considered Near Threatened (Utevsky et al, 2010), but only the first species is listed in nature conservation international conventions (IUCN, CITES Appendix II, Berne Convention) and national legislations. Little is known about the distinct distribution, ecology and endangerment of the two species and about the anthropic influence on them respectively, yet the "H. medicinalis" samples from the southern Balkan Peninsula and Turkey, cited in literature, and the majority of commercially, exploited medicinal leeches from the same regions were actually H. verbana (Trontelj et al, 2004;Siddall et al, 2007;Laufer et al, 2008). Accordingly, appropriate taxonomic correction of international and national conservation conventions and legislation is a necessity.…”

“…Nowadays, their anticoagulant and antiinflammatory substances are of medical and pharmaceutical attention, and the direct therapeutic application of the now commercially bred leeches is revived, e. g. for restoring blood circulation and ameliorating congestion after reconstructive surgery (Siddall et al, 2007;Sket & Trontelj, 2008). Only recently it was proved that most commercially available leeches are not Hirudo medicinalis Linnaeus, 1758, but the long-neglected, more colourful and thermophilic H. verbana Carena, 1820, or sometimes H. orientalis (Trontelj et al, 2004Kutschera, 2006;Siddall et al, 2007).…”