a1 Department of Environmental Sciences, Section of Conservation Biology, University of Basel, St Johanns-Vorstadt 10, CH-4056 Basel, Switzerland
a2 Laboratorio de Zoología de Invertebrados 1, Departmento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, (8000) Bahía Blanca, Argentina
Temperature can be a limiting factor on parasite development. Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection by R. limacum in populations of the land snail Arianta arbustorum is highly variable (0–78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4–7 months. Winter survival of host snails was negatively affected by R. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus, R. limacum survives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence of R. limacum.
(Received November 24 2011)
(Revised February 02 2012)
(Accepted February 05 2012)
(Online publication March 23 2012)
c1 Corresponding author: Department of Environmental Sciences, Section of Conservation Biology, University of Basel, St Johanns-Vorstadt 10, CH-4056 Basel, Switzerland. Tel: +41 61 267 08 46. Fax: +41 61 267 08 32. E-mail: firstname.lastname@example.org