Aspects of Pairing and Reproduction in the Hermaphrodite Freshwater Snail
Biomphalaria Glabrata (Gastropoda: Pulmonata)

Vianey‐Liaud, Monique; Dussart, G.

doi:10.1093/mollus/68.3.243

Cited by 10 publications

(9 citation statements)

References 24 publications

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“…Moreover, these correlations were more often detected in QTT than in DOY (see Web Appendixes 1 and 2). Similar results have been found in other studies of snails (Locher & Baur, 2000 ;Vianey-Liaud & Dussart, 2002). This is surprising since some negative correlations were expected in our study, as a result of re-allocation between fitness-associated traits (Reznick, 2000).…”

Section: (C) Limited Mating Activitysupporting

confidence: 93%

Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snailBiomphalaria pfeifferi

et al. 2008

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SummaryInbreeding species of hermaphroditic animals practising copulation have been characterized by few copulations, no waiting time (the time that an isolated individual waits for a partner before initiating reproduction compared with paired individuals) and limited inbreeding (self-fertilization) depression. This syndrome, which has never been fully studied before in any species, is analysed here in the highly selfing freshwater snail Biomphalaria pfeifferi. We conducted an experiment under laboratory conditions over two generations (G 1 and G 2 ) using snails sampled from two populations (100 individuals per population). G 1 individuals were either isolated or paired once a week (potentially allowing for crosses), and monitored during 29 weeks for growth, fecundity and survival. Very few copulations were observed in paired snails, and there was a positive correlation in copulatory activity (e.g. number of copulations) between the male and female sexual roles. The waiting time was either null or negative, meaning that isolated individuals initiated reproduction before paired ones. G 2 offspring did not differ in hatching rate and survival (to 28 days) between treatments, but offspring from paired individuals grew faster than those from isolated individuals. On the whole, the self-fertilization depression was extremely low in both populations. Another important result is that paired G 1 individuals began laying (selfed) eggs several weeks prior to initiating copulation : this is the first characterization of prior selfing (selfing initiated prior to any outcrossing) in a hermaphroditic animal. A significant population effect was observed on most traits studied. Our results are discussed with regard to the maintenance of low outcrossing rates in highly inbreeding species.

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Section: (C) Limited Mating Activitysupporting

confidence: 93%

Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snailBiomphalaria pfeifferi

et al. 2008

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“…Toda a superfície externa do corpo desses moluscos é provida de células neurossensoriais, que são muito abundantes ao longo das margens do pé e na região anterior do corpo, incluindo os tentáculos e as pregas orais (HYMAN 1967, CHEVALIER et al 2000. Entre os moluscos terrestres, a quimiorrecepção está associada à percepção do ambiente, à comunicação entre indivíduos de uma mesma espécie, ao comportamento de corte e cópula (COOK 1992, VIANEY-LIAUD & DUSSART 2002, à escolha e encontro de alimentos (STEPHENSON 1979, IGLESIAS & CASTILLEJO 1999, CHEVALIER et al 2000 e ao comportamento agregativo (DUNDEE et al 1975). …”

Section: Resultsunclassified

“…Evidências a respeito da influência de compostos químicos sobre o comportamento agregativo de moluscos gastrópodes vêm sendo obtidas por meio de observações a campo e de experimentação em laboratório (COOK 1992, ANSELL 2000, CHEVALIER et al 2000, FRATINI et al 2001, VIANEY-LIAUD & DUSSART 2002.…”

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Comportamento agregativo em Subulina octona (Brugüière) (Mollusca, Subulinidae)

2006

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que favorecem a agregação incluem características do ambiente, tais como diferenças no microclima, heterogeneidade do habitat e distribuição em manchas de recursos; assim como fatores relacionados à reprodução e à sobrevivência dos moluscos, tais como a probabilidade de encontrar um parceiro sexual e o risco de dessecação (KLEEWEIN 1999, COOK 1992 Sub Subulinidae). ulinidae). ulinidae). ulinidae). ulinidae). The current study aimed to verify the existence of aggregative behavior in Subulina octona (Brugüière, 1789) and to obtain behavioral evidence of chemical mediation of this behavior. We used 150 adult animals allocated in 15 boxes with humus (10 animals per box). In each box we placed four identified plastic disks in an equidistant position. These disks worked as shelters for the animals. In experiment I, 10 animals were put in the middle of each box. After 24, 48, 96, 120, 144, and 168 hours we observed the number of formed aggregations, as well as the position of the aggregates (in each shelter), the number of individual per aggregation and the number of isolated individuals. In order to test the hypothesis of conditioning of disks by chemicals compounds, the experiment II was carried out. All the individuals were transferred to other boxes with humus, three new disks and the disk containing the larger aggregate after the 168 hours of the experiment I (denominated conditioned disk). We verified, after 24 and 48 hours, the number of individuals below the conditioned disk. In experiment I, aggregations were observed in every used box and in every time intervals. In all boxes, there was a significant increase in the number of individuals per aggregation and a reduction in the number of isolated individuals until the end of the experiment (ANOVA, p < 0.005). In experiment II, after 24 hours, six from 15 boxes presented aggregations under the conditioned disk, and after 48 hours, seven boxes presented aggregations under conditioned disk. These were the aggregations with a larger quantity of individuals, which suggests the conditioning of the used disks by some factor, possibly a chemical compound. KEY WORDS. Aggregation; chemical communication; land snail.RESUMO. O objetivo deste trabalho foi verificar a existência de comportamento agregativo na espécie Subulina octona (Brugüière, 1789) e obter evidências da mediação química desse comportamento. Foram utilizados 150 animais adultos, distribuídos em 15 caixas com terra vegetal (10 animais por caixa). Em cada caixa foram colocados quatro discos plásticos identificados, em posição eqüidistante, os quais serviram como abrigos para os animais. No experimento I, foram colocados 10 animais no centro de cada caixa. Após 24, 48, 96, 120, 144 e 168 horas foram observados o número de agregados formados, a posição dos agregados (sob qual abrigo), o número de indivíduos por agregado e o número de indivíduos isolados. No experimento II, todos os indivíduos foram transferidos para outras caixas contendo terra vegetal, três novos discos e o disco que continha o maior agregado...

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“…Biomphalaria glabrata is a facultative self-fertilising hermaphrodite such that snails will preferentially outcross when given access to a mate, but when isolated will usually reproduce through self-fertilisation (e.g. Vianey-Liaud and Dussart, 2002; and personal observations). For example, our laboratory population is in Hardy–Weinberg equilibrium for all the loci used in this study.…”

Section: Methodsmentioning

confidence: 99%

Three genes involved in the oxidative burst are closely linked in the genome of the snail, Biomphalaria glabrata

Blouin

Bonner

Cooper³

et al. 2013

International Journal for Parasitology

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Allelic variation at the Cu–Zn superoxide dismutase (SOD1) locus has been shown to be associated with resistance of the snail, Biomphalaria glabrata, to infection by the trematode parasite, Schistosoma mansoni. SOD1 catalyses the production of hydrogen peroxide, a known cytotoxic component of the oxidative burst used in defence against pathogens. In our laboratory population of B. glabrata, the most resistant allele at SOD1 is over-expressed relative to the other two alleles. Because hydrogen peroxide also causes oxidative stress on host tissues, we hypothesised that over-expression of SOD1 might be compensated by epistatic interactions with other loci involved in oxidation–reduction (redox) pathways. Catalase, peroxiredoxins and glutathione peroxidases all degrade hydrogen peroxide. We tested whether alleles at each of these loci were in linkage disequilibrium with SOD1 in our population, as might be expected given strong epistatic selection. We found that SOD1, catalase (CAT) and a peroxiredoxin locus (PRX4) are in strong linkage disequilibrium in our population. We also found that these loci are tightly linked, within 1–2 cM of each other, which explains the high linkage disequilibrium. This result raises the possibility that there is a linked cluster of redox genes, and perhaps other defence-relevant genes, in the B. glabrata genome. Whether epistatic interactions for fitness actually exist among these loci still needs to be tested. However the close physical linkage among SOD1, PRX4 and CAT, and subsequent high disequilibrium, makes such interactions a plausible hypothesis.

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Aspects of Pairing and Reproduction in the Hermaphrodite Freshwater Snail Biomphalaria Glabrata (Gastropoda: Pulmonata)

Cited by 10 publications

References 24 publications

Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snailBiomphalaria pfeifferi

Prior selfing and the selfing syndrome in animals: an experimental approach in the freshwater snailBiomphalaria pfeifferi

Comportamento agregativo em Subulina octona (Brugüière) (Mollusca, Subulinidae)

Three genes involved in the oxidative burst are closely linked in the genome of the snail, Biomphalaria glabrata

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