The history of butterfly recording on Thásos is not extensive and the first significant contribution appeared as recently as 1991 (Littler 1991). Five years later, J.D. Holloway (1996) published a review of the butterfly fauna of Thásos, listing sixty-eight confirmed species. Possible records of a further six species are discussed and one of these, Anthocharis gruneri, has since been confirmed (Abadjiev 2000). Pamperis (1997) maps records for 62 species for Thásos, including five not mentioned by Holloway. However, Pamperis indicates that these are unconfirmed and the record of Pyrgus serratulae has since been withdrawn. Leptidea duponcheli, mapped by Pamperis, has recently been confirmed by Sylvia van Leeuwen and Bart van Tooren. I have added Pyronia tithonus, seen in open woodland above Potamia in 2007. Four more potential additions were included in a list of butterflies recorded from Skala Potamias (Chilton 1999). In 2011 & 2012 Langourov et al. (2013) discovered Chilades trochylus breeding on the south coast of the island. This amounts to a total of eighty-five butterfly species which have been reported from Thásos.
In a comprehensive review of the butterfly fauna of the Aegean islands, Dennis et al (2001) consider that 69 species have been reliably recorded from Thásos (more than for any other Aegean island) and predict that a further five species should be recorded given their distribution in the region. One of these, Charaxes jasius has already been reported by Chilton (1999) and hence should be added to the Thásos list. The information presented in Dennis et al (2001) indicates that seven of the unconfirmed species included in Holloway (1996), Pamperis (1997) and Chilton (1999) have not been recorded on any of the Aegean islands and are therefore unlikely to have been correctly identified. The remaining six species (plus Heodes tityrus reported in 2002) are possibly present on Thásos but confirmation is desirable. The addition of Leptidea duponcheli (which is otherwise known in the Aegean only from Samothraki) and Pyronia tithonus was not predicted by Dennis et al (2001) and, thus, the Thásos checklist consists of seventy-three confirmed species, seven unconfirmed species, and a further four that should be present but have probably been overlooked. Holloway (1996) attributes this diversity to the lush wooded habitats of Thásos and its proximity to the Greek mainland. This is supported by the detailed analysis presented by Dennis et al (2000, 2001), who conclude that distance from mainland coasts and island area are the main factors in promoting butterfly diversity on the Aegean islands. The only other islands with more than sixty recorded species are Lesvos and Samos, eastern Aegean islands that are very close to the coast of Turkey.
Various browns and blues predominate amongst the Thásos fauna but there is also the spectacle of the swallowtails and, locally in coastal areas such as Skala Potamia, the beautiful southern festoon. In the uplands, as on the flanks of Profitis Ilias, Queen of Spain fritillaries sparkle on montane limestone grassland amongst the pine forests. Despite this diversity, butterflies are rarely abundant on Thásos, with most individuals being seen during early summer in the low-lying olive groves in the cool of late afternoon. Dennis et al (2001) comment that "a striking feature of the Greek islands is the very low population density of many species" and speculate that this may be due to predation by ants.
Whilst many species are easy to identify with standard European field guides, such as Higgins & Hargreaves (1983), there are difficult groups amongst the graylings, blues and skippers, for instance, that require careful scrutiny and occasionally dissection for accurate identification. Pamperis (1997) provides a lavish and beautifully illustrated account of the Greek fauna with hundreds of stunning photographs but some of the identification characters employed in this book for the more difficult species have since been questioned.
Abadjiev, S. 2000. Anthocharis gruneri gruneri Herrich-Schaffer, (Lep.: Pieridae) new for the Greek Islands. Entomologist's Record and Journal of Variation, 112: 131-132.
Chilton, L. 1999. Plant list for Thasos. Marengo Publications.
Coutsis, J. 1979. About two recent butterfly records from the island of Thassos, Greece. Entomologist's Record and Journal of Variation., 91: 57
Dennis, R.L.H., Shreeve, T.G., Olivier, A. & Coutsis, J.G. 2000. Contemporary geography dominates butterfly diversity gradients within the Aegean archipelago (Lepidoptera: Papilionoidea, Hesperoidea). Journal of Biogeography, 27: 1365-1383.
Dennis, R.L.H., Olivier, A., Coutsis, J.G. & Shreeve, T.G. 2001. Butterflies on islands in the Aegean archipelago: predicting numbers of species and incidence of species using geographical variables. Entomologist's Gazette, 52: 3-39.
Higgins, L.G. & Riley, N.D. 1983. Field guide to the butterflies of Britain and Europe. London, Collins.
Holloway, J.D. 1996. The butterflies (Lepidoptera) of the northern Aegean island of Thásos. Entomologist's Gazette, 47: 143-149.
Langourov, M.S., Simov, N.P. & Abadjiev, S.P. 2013. Chilades trochylus (Freyer, ) (Lep.: Lycaenidae), new for the North Aegean Islands. Entomologist's Record and Journal of Variation, 125: 137-143.
Littler, E. A. 1991. Autumn and spring butterflies of Thassos (Lepidoptera: Hesperioidea & Papilionoidea). Phegea, 19: 25-28.
Pamperis, L. 1997. The butterflies of Greece. Bastas-Plessas, Athens.