First records of Hyalomma aegyptium (Acari: Ixodida: Ixodidae) from the Russian spur-thighed tortoise, Testudo graeca nikolskii, with an analysis of tick population dynamics.

During the fall of 1995 and the spring of 1996, 77 statistically comparable tick collections, comprising 792 specimens, were made from adults of the Russian spur-thighed tortoise, Testudo graeca nikolskii, at 4 sites along Russia's Black Sea coast. These are the first tick collections reported from T. g. nikolskii since its recognition as a taxonomic entity. All ticks were determined to be Hyalomma (Hyalomma) aegyptium, a common tortoise parasite in southern Russia that in 1930 was erroneously designated the type of subgenus Hyalommasta. Male ticks were recovered from more tortoises (67) than were females (57) or immatures (14), and nymphs were seen only in the fall. Significantly more ticks parasitized male tortoises than females, perhaps because males of T. g. nikolskii have larger home ranges. However, no functional relationship was found between tortoise ventral surface area and degree of tick infestation. Like other tortoise ticks, H. aegyptium is expected to decline in concert with its increasingly threatened hosts.