Feeding, maintenance and reproduction of Microplana terrestris (Platyhelminthes: Tricladida: Continenticola: Geoplaninae: Microplaninae) under laboratory conditions

Abstract

Seven specimens of Microplana terrestris were kept individually to establish seven dynasties of flatworms. Flatworms were fed almost exclusively on chopped Eisenia fetida. Feeding commenced sometimes within 2 minutes and continued for up to 11.5 hours. One specimen lived for 39 months, and some individuals over-grew to more than double normal size. No reduction in feeding during cocoon production was observed. Over four years 77 adults produced 407 cocoons and 1518 hatchlings, 1204 without mating. A total of 18 first, 142 second, 235 third and 12 fourth generation cocoons were obtained. The first cocoon was shed 195 ± 75 days after hatching, the median shedding frequency was 30 days thereafter. The number of cocoons shed per flatworm was 5.7 ± 7.3 at a rate of up to 0.37 cocoons per flatworm per week. There was a relationship between the time to first shedding and longevity and between longevity and the number of cocoons shed. The incubation period was 28 ± 2 days at 16.9°C, 40 ± 3 days at 11.5°C and 85 ± 8 days at 7.1°C. Differences in generation times were apparent between flatworms in different dynasties. Fortnightly fed M. terrestris shed smaller cocoons and produced smaller hatchlings than weekly fed flatworms. Over-growers shed larger cocoons. The number of hatchlings per cocoon was 5.52 ± 1.8. Hatchling size ranged from 1 mm to over 1 cm. The number and size of hatchlings did not increase with cocoon size. A relationship existed between longevity and the number of hatchlings per flatworm. The median number of hatchlings per flatworm was 12. Differences in reproductive strategies were apparent between the dynasties. Bisected M. terrestris were capable of regeneration.