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Reproduction of Balea (Pseudalinda) fallax (Rossmassler, 1836) (Gastropoda: Pulmonata: Clausiliidae) kept under laboratory conditions

100%

Sulikowska-Drozd A., Maltz T. K.

Folia Malacologica

2012

tom 20

nr 1

Balea fallax (Rossm.) collected from the Roztocze Upland (SE. Poland) was kept in the laboratory for four years. Observations were conducted between March and October when the snails were kept at room temperature (18-25°C); in winter they were stored at 3°C. The egg-laying period started in late March and lasted till October, with maxima in spring and early autumn. The snails laid oval, gelatinous eggs with separatecalcium carbonate crystals in the external envelope (average egg size 1.96 × 1.73 mm). The eggs were deposited in batches (up to 14 eggs at a time) or singly. The number of batches per snail per year ranged between 1and 4. Snails isolated before maturation laid defective eggs which failed to develop, which suggest that the speciesis incapable of uniparental reproduction or at least the ability is very limited. The reproduction rate decreased during consecutive years, probably as a result of the aging or the shortage of allosperm in isolated individuals.Compared to batches of typically oviparous clausiliids, eggs of B. fallax hatched slightly earlier (interval between oviposition and hatching lasted 8-10 days at room temperature). It is likely that the adults retained developing eggs in the uterus for a short time. The juveniles needed at least 6 months to attain the ultimates hell size.

Egg retention in the clausiliid Balea (Pseudalinda) fallax (Rossmassler, 1836) from Roztocze (S. E. Poland)

80%

Sulikowska-Drozd A., Maltz T. K., Stachyra P.

Folia Malacologica

2012

tom 20

nr 1

Adults of Balea fallax sampled monthly from the Roztocze Upland were dissected to examine the occurrence of uterine egg retention. Developing eggs were found in snails collected between May and August. In June more than 60% of the studied individuals were gravid, while in other months egg-retaining snails constituted less than 10% of the sample. The number of retained eggs ranged from 3 to 17 (mean 12.3) and was not related to the adult shell size. In June the majority of eggs contained shelled embryos (maximum shell size1.1 whorl). The reproduction mode of B. fallax is compared with those of other ovoviviparous clausiliids of Central Europe.

Ograniczanie wyników

2 Folia Malacologica

2 Maltz T. K.

2 Sulikowska-Drozd A.

1 Stachyra P.

2 2012

Wyniki wyszukiwania

Reproduction of Balea (Pseudalinda) fallax (Rossmassler, 1836) (Gastropoda: Pulmonata: Clausiliidae) kept under laboratory conditions

Egg retention in the clausiliid Balea (Pseudalinda) fallax (Rossmassler, 1836) from Roztocze (S. E. Poland)