Helix salomonica Nägele, 1899 (Gastropoda: Helicidae): annual activity cycles in its natural habitat in southeastern Turkey

Abstract

ABSTRACT This research focused on the annual activities, including aestivation, hibernation and reproductive behaviours, of the endemic species Helix salomonica Nägele, 1899 in its natural habitat in Şırnak, Turkey. Within an area of 900 m2, a population of at least 600 snails was monitored for a year. Eighty snail specimens were sampled and measured, with twenty of them observed in a laboratory environment (within a cage) for comparison of circannual snail rhythms. The annual activity patterns of H. salomonica revealed distinctive behaviours. The total hibernation period lasted around 85 days on average, with continuous hibernation lasting approximately 57 days and intermittent hibernation lasting about 28 days. In March and November, copulation occurs. Durıng the sprıng,the average number of eggs was 63, with an average diameter of 2.85 mm and a weight of 0.28 g. On average, eggs hatched after 34 days, during the second and third weeks of May. Aestivation persisted continuously from late May to early November, averaging 165 days. Arousal and the observation of juvenile snails coincided in the second week of November. Consequently, the annual activity cycles of H. salomonica are intricately regulated by a complex interplay of internal (endogenous) rhythms and external factors, with dormancy phases predominantly governed by circannual rhythms.