Pomatiopsis lapidaria

Reproduction

     Pomatiopsis lapidaria's life cycle is direct (Dundee, 1957). This means that there are no larval stages before the individual reaches adulthood.  Slender Walkers can only reproduce sexually (Dundee, 1957).  They are diecious (DeWitt, 1952), meaning that male and female reproductive organs are on separate individuals.  This requires the snail to find a member of the opposite sex, rather than any member of the same species, as a monecious animal could.  However, they will not travel far looking for a partner (Dundee, 1957).  Dundee (1957) says that Pomatiopsis lapidaria will not intentionally move more than 6 feet throughout their lifetime. 

      Copyright hannah barrett and licensed for reuse under this Creative Commons Licence (Cloudy Lake Scene)

     Mating times follow the change of seasons as well as daily weather variations (Dundee, 1957).  Pomatiopsis lapidaria reproduces twice a year: once in spring and once in fall (Dundee, 1957).  The exact dates of copulation vary just as weather patterns for each year do (Dundee, 1957).  They begin mating shortly after spring arrives and finish their second mating session before the onset of the cold (Dundee, 1957).  The Slender Walker does not seem to prefer certain times of the day for mating but does mate more often on cloudy, damp days (Dundee, 1957).  This preference is likely for the female’s benefit, as her head-foot area is outside of the shell during copulation (Dundee, 1957).  The moist days keep her body from drying out while copulating on land (Dundee, 1957). 

    

     After copulation, the female finds a suitable place for her eggs to develop.  For Pomatiopsis lapidaria this is near, but not directly in, water (Dundee, 1957).  The eggs can be laid on flat ground or a vertical surface (Dundee, 1957).  Dundee (1957) says that the number of eggs each female lays throughout the year is quite variable.  Once the eggs are laid, Dundee (1957) observed a seven week lag before hatching in the laboratory.  However, he also noted that this time varied depending on room temperature and guessed that the actual hatching time would be less than that observed in the laboratory.  Slender Walkers use their radula to rasp their way out of the shell (Dundee, 1957).