The effect of isolation on the life-history traits of Pseudosuccinea columella (Pulmonata: Lymnaeidae)

Abstract

Growth, survival and reproduction in the family Lymnaedae (Mollusca: Prosobranchia) have been widely studied. Snails of this taxon are known to be hermaphrodites and to reproduce both by selffertilization (selfing) and outcrossing. The proportion of selfing in natural populations of lymnaeid snails is to our knowledge unknown, but presumably more important in small populations and in stable environments.Pseudosuccinea columella (Say 1817) is in importance the second intermediate host of the trematode Fasciola hepatica Linnaeus, 1758 in Cuba (Mauri 1981). As this parasite is the causal agent of fasciolosis, a disease that affects domestic animals as well as people, the study of its hosts' biology may help the control of its transmission.Several studies have been published on the demography of lymnaeids (Vergani 1955, DeWitt & Sloan 1958, Malek & Chrosciechowski 1964, Martinez & Miranda 1968, Morales et al. 1983, 1985). Regarding Cuban populations, some studies compare the biology of P. columella with that of Fossaria cubensis, the most important intermediate host of F. hepatica, (Ferrer et al. 1988(Ferrer et al. , 1989) and other works emphasize on the biology and demography of F. cubensis (Yong et al. 1996). However, most of the previous papers based their results on groups of snails, where competition for available resources takes place. groups, sometimes deviations of expected results have been observed as populations grow older and their size is reduced due to the death of some snails. The present research aims to report on the life-history traits of P. columella under the effect of complete isolation, fertilization being accomplished only by selfing; compared to snails raised together with a conspecific partner, allowed to both crossand self-fertilization and where intra-specific communication takes place. MATERIALS AND METHODSThe parental snails for the study were collected from a temporary pond in La Palma municipality, Pinar del Rio Province, located west of the island of Cuba. The specimens were removed from their habitat with a hand sieve, sampling the bottom as well as the vegetation present on the shores, then taken to the laboratory on wet filter paper inside plastic cases. Upon arrival to the laboratory all snails (60 in total) were placed in a petri dish (PYREX® USA, 88 ml of water volume) for 15 days with a pool of algae of the genera Lyngbya, Leptolyngbya, Phormidium and Schimidleinema as the food source. After seven days a number of egg masses was removed and placed into another similar dish, then 40 newly hatched snails were randomly selected for the life tables experiment. Twenty newly-hatched individuals (isolated snails) were raised in complete isolation (one snail per dish) and the other 20 (paired snails) were grown in pairs (two snails per dish).The age zero of the experiment was considered as the week when all 40 newly hatched snails emerged from their egg masses. All mollusks were raised using the petri dishes and pool of algae mentioned above as container and food source respectively ...

SPATIAL DISTRIBUTION OF LYMNAEIDAE (MOLLUSCA, BASOMMATOPHORA), INTERMEDIATE HOST OF Fasciola hepatica LINNAEUS, 1758 (TREMATODA, DIGENEA) IN BRAZIL

“…1; 95.7%) and is certainly the most important intermediate host in Brazil. This is probably due to its biological aspects, such as its high capacity for self-fertilization, favorable condition in dispersion and colonization of new habitats 20,35 . Pseudosuccinea columella is commonly found in most human or animal fasciolosis outbreaks while the occurrence of G. viatrix is, currently, restricted to the state of Rio Grande do Sul 24,33,63,76,101 and in Minas Gerais 22 .…”

Are there interactive effects of mate availability and predation risk on life history and defence in a simultaneous hermaphrodite?

“…, 1996), whereas preferentially selfing individuals experience increased fecundity when isolated (Wedekind et al. , 1998; Gutiérrez et al ., 2001a,b). Interestingly, studies that have observed reduced fecundity by isolated snails also reported a long waiting time prior to self‐fertilization (Jarne et al.…”

“…Interestingly, studies that have observed reduced fecundity by isolated snails also reported a long waiting time prior to self‐fertilization (Jarne et al. , 1991, 2000) whereas studies documenting high fecundity of isolated snails report little or no waiting time (Gutiérrez et al ., 2001a,b). In contrast to previous research on different populations of P. acuta (Wethington & Dillon, 1997; Tsitrone et al.…”

Snails as Biomonitors of Oil-Spill and Bioremediation Strategies

“…It is a hermaphroditic pulmonate capable of withstanding prolonged periods of desiccation and anoxia. They have a short life cycle of approximately 6 months (Gutierrez et al, 2001), hatching from eggs after 12 to 15 days incubation and growing rapidly from 5 mm to adult size (15 mm) within a 6-week period. These snails are intermediate hosts to liver flukes and have been the subject of toxicological studies (Tate et al, 1997(Tate et al, , 2000.…”