Genetic similarity and diversity of parthenogenetic and bisexual populations of the freshwater snail Melanoides tuberculata (Gastropoda: Prosobranchia)

Abstract

Genetic variability and similarity were analysed in four parthenogenetic and five bisexual populations of the snail Melanoides tuberculata found in Israel. Electrophoretic studies of six enzymatic systems revealed 28 zones of activity. The average genetic identity between populations was low-0.725. A particularly low similarity (0.628) was obtained between parthenogenetic populations, compared to the average of 0.822 observed among the bisexual ones. The percentage of fixed electrophoretic bands in parthenogens was 53.9% compared to 12.5% observed in bisexual populations. The diversity of parthenogenetic populations was found to be lower than those of bisexual. The amount of electrophoretic diversity between populations of the parthenogenetic group was found to be 80%, whereas within the bisexual group the diversity between populations was only 42%.

Growth models and shell morphometrics of two populations of Melanoides tuberculata (Thiaridae) living in hot springs and freshwater pools

“…Pointier (1993) reported that M. tuberculata snails from the marshy forest zone of Guadeloupe, French West Indies, reached a length of 10 mm after 4.5 months, 15 mm after 14 months, and in more than 30 months they reached 20 mm. Experimentally Livshits and Fishelson (1983) reported that M. tuberculata snails become fertile when reaching 15-16 mm at the age of six months and continued to grow to attain a maximum length of 27 mm, at a water temperature of 26-27 o C. Although there were differences between the two populations in length, the relationships of the shell length to shell width, aperture length, and aperture width were linear and similar regression equations were obtained. The relationship of the shell length to shell weight and body weight were curvilinear.…”

“…This problem was overcome by excellent conditions at hot springs. Livshits and Fishelson (1983) reported that M. tuberculata snails are mainly algivorous or detrivorous. In relatively warm water at a desert spring in United Arab Emirates (29.0-31.0 o C) M. tuberculata snails reached 26.0 mm in length (Ismail & Arif 1993).…”

“…1988;Ismail 1990;Ismail & Arif 1991). This feature has attracted the attention to study its population dynamics, and reproduction (Livshits & Fishelson 1983;Dudgeon 1986;Ismail & Arif 1993).…”

Estudo da composição taxonômica e da densidade de macroinvertebrados bentônicos no sistema de lagoas naturais do vale do médio Rio Doce (MG), com ênfase na espécie de molusco exótica Melanoides tuberculata (Müller, 1774)

“…Os embriões dessa espécie invasora desenvolvem-se em uma bolsa posterior à cabeça, sob o manto (BEDÊ, 1992), podendo cada indivíduo carregar de 1 a 71 embriões na sua bolsa reprodutiva (com número variando de acordo com o tamanho do indivíduo) (LIVSHITS & FISHELSON, 1983). Estes moluscos alimentam-se principalmente de algas perifíticas, partículas orgânicas e bactérias depositadas sobre o sedimento (DUDGEON, 1989;POINTIER et al, 1991), o mesmo tipo de alimento utilizado por diversas espécies de moluscos nativos, sendo, portanto potenciais competidores, que devido ao elevado potencial reprodutivo, poderão excluí-las competitivamente.…”

“…Esta espécie exótica ocupa diversos tipos de habitats, incluindo águas doces e salobras, nascentes térmicas, canais de irrigação, rios e lagoas (em regiões tropicais, subtropicais e temperadas) em diferentes graus de eutrofização (LIVSHITS & FISHELSON, 1983;POINTIER & MCCULLOUGHT 1989;ABÍLIO, 2002).…”