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Abstract

The life table characteristics of the invasive snail Physa acuta were assessed in the laboratory using the individuals occurring in a newly colonised area in Burdwan, West Bengal, India. Using the changes in the shell length and the body weight of the snails as surrogate, the population growth of the snails was estimated along with longevity and the fecundity schedule. The cohort of P. acuta lived for a maximum of 22 weeks with a life expectancy (ex) of 7.27 weeks and the age-specific survivorship being 0.825. Increment of the shell length of the snails complied with the von Bertalanffy growth equation, lt = 11.75(1 − exp−0.17(t−0.06)), and the observed and the expected data of the length at time t (lt) did not vary significantly (z score = 0.230; P = 0.818; n=20 pairs). Following attainment of sexual maturity between 28 and 42 days, oviposition continued till 20 weeks time, with 0.1-10 eggs laid by each individual. The eggs present per capsule remained between 01 and 11, whilst the net reproductive rate (R0), intrinsic rate of increase (rm) and the finite rate of increase (λ) were 116.07, 0.1 and 1.11, respectively. The observations are similar to those made earlier on the same species but from African and South American continents. The results of the present observation are pioneer in providing the initial studies about the life history of the invasive snail P. acuta in Indian context. Using the present information as a basis, further studies including long-term population monitoring should be initiated to understand the effects of the invasive snail P. acuta in the freshwater ecosystem of West Bengal, India.

Abstract

A finding of the subterranean population of the Caucasian invasive snail on the depth of 30 m below Odesa in Southern Ukraine is discussed.

Abstract

Thirty-six species of terrestrial molluscs were found in the dry grasslands and rock outcrops of the study area, including three that were not previously known for Central Ukraine: Granaria frumentum, Pupilla bigranata and Mediterranea inopinata. These species are relics related to dry open habitats and require conservation in Ukraine on the national level, G. frumentum is already listed in the Red Book of Ukraine, and the other two should be listed in its next edition. It is proposed to create the new protected areas in the most important newly revealed locations of these species. These rocky areas also retain the high diversity of land molluscs in the region. The invasive snail Xeropicta derbentina was found for the first time on the DNIPRO Upland, on the edge of natural dry grassland. The rare native snail Morlina glabra was recorded for the first time in Kyiv Region, it is proposed to be included into the regional red list.

intermediario de nematodes de interés sanitario-veterinario en Goias, Brasil Rev. Patol Trop. 39 3 199 210 Pritchard, M.H., Kruse, G.O. (1982): The collection and preservation of animal parasites . University of Nebraska Press, Nebraska, USA 141 pp. Pritchard M.H. Kruse G.O. 1982 The collection and preservation of animal parasites University of Nebraska Press Nebraska, USA 141 Thiengo, S., Faraco, A.F., Salgado, N.C., Cowie, R.H., Fernandez, M. A. (2007): Rapid spread of an invasive snail in South America: the giant African snail Achatina fulica . Biol. Invasions , 9: 693