| Popis: |
The freshwater planarian are often used in laboratory studies as proposed organisms to the environment control that is used in the toxic and genotoxic evaluation of the environment, as bioindicators of water quality and biologic control of mosquito larvae agent. However, data on the biology of laboratory planarians are scarce. This study aims to give subsidies for studies that use planarians as animal model, describing the reproductive biology of Girardia tigrina in relation to the following aspects: quantity and length of the egg capsules, hatching, quantity and size of the new born animals in each egg capsule. For this, a sample of 50 sexual mature specimens were placed in plastic recipients with water under controlled temperature (18oC 1oC) and observed daily. The egg capsules, which were attached to the substrate by a stalk, were removed with a brush, measured under a stereomicroscope, separated in micro tubes and catalogued. In 13 months the results showed a production of 2136 egg capsules with 5745 births, being the highest index in May 2006 with 406 egg capsules and the lowest in September with only 39 capsules. The average e time of eclosion was 19.9 days and the size average of the new born animals was 3.0 mm. The present study shows that under laboratory conditions, with temperature and food controlled, G. tigrina reproduces the whole year presenting period’s larger and smaller posture. |
