Field and laboratory studies on the life-cycle, growth and feeding preference in the hairy snail Trochulus hispidus (L., 1758) (Gastropoda: Pulmonata: Hygromiidae)
Abstrakt
For the first time the life cycle of the common land snail Trochulus hispidus was completely described in Central Europe (Poland). This is a semelparous species predominantly with an annual life cycle and the reproductive period lasting from April till October.
The first young snails hatch in spring, grow rapidly in summer and reach ca. 4 whorls until winter. In spring of the next year they mature and reproduce.
After that they die. There is hardly any growth from late autumn till early spring.
The average proportional growth rate is ca. 0.3 whorl/month in the wild. The fastest growth is present in the youngest snails and then gradually decreases over the course of their age.
Laboratory and field observations allowed for establishing the following life cycle parameters: eggs calcified, almost spherical, ca. 1.5 mm, laid in spring and summer in batches of between 1 and 47. Time to hatching is 6-24 days, hatching is asynchronous; newly-hatched snails have approximately 1.5 whorls.
Analysis of food preferences revealed, that T. hispidus tends to restrict its diet during the life. Generally the youngest snails equally consumed leaves of all four tree species offered (Fraxinus excelsior, Acer pseudoplatanus, Tilia cordata and A. platanoides) whereas adults preferred F. excelsior over A. pseudoplatanus and A. platanoides.