Chemical conditioning of the environment by the freshwater pulmonate snails (<i>Biomphalaria glabrata</i>) and its effect on growth and natality rates

Thomas, J. D.; Goldsworthy, G.J.; Benjamin, Marcus

doi:10.1111/j.1469-7998.1974.tb04378.x

Cited by 12 publications

(4 citation statements)

References 11 publications

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“…The experimental method used has been described by Thomas, Goldsworthy & Benjamin (1974). Each assay snail was kept isolated in 200 ml of medium in 1 of 10 compartments of an inner tank made of white, opaque perspex.…”

Section: Methodsmentioning

confidence: 99%

“…Further increases in snail numbers or a decrease in volume or conditioning time can have the opposite effect. It has further been shown that these effects can be induced by chemical conditioning alone (Thomas, 1973 ;Thomas, Goldsworthy & Benjamin, 1974). The purpose of the investigations described in the present paper is to measure the effects of chemical environments produced by plant fed snails kept at densities of 10, 20, 30, 50, 90 and 170 snails per 6 1 on some of their growth characteristics and metabolism.…”

Section: Introductionmentioning

confidence: 96%

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Studies on the chemical ecology of Biomphalaria glabrata: The effects of chemical conditioning by the snails kept at various densities on their growth and metabolism

1975

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It has been shown that heterotypically conditioned media (Het. C.M.) produced by lettuce fed snails maintained at various densities can influence the allometric growth and the rates of specific growth, ingestion, egestion, assimilation and heart beat of isolated assay snails. The growth rate of the assay snails was enhanced by increasing the density of snails producing the Het. C.M. to an optimum threshold of one snail per 100 ml. Further increases in density were followed by a decline in their growth rate. The higher growth achieved by the assay snails in the optimum treatment can be attributed to the fact that their specific growth rates over the first three weeks of the experiment were higher than those of snails in other treatments. Ingestion and assimilation correlated well with specific growth rates. Percentage assimilation values are high, ranging from 78.4 to 89.6%. The onset of reproductive activity is followed by a dramatic decline from approximately 26 % to 5 % in the gross efficiency of utilization of food for somatic growth. Snails not receiving Het. C.M. from the outer tanks have a relatively higher ratio of specific growth rate in weight to length than was the case with snails in the other treatments. The heart beat rates of snails in the Het. C.M. produced by snails at densities of 80 to 160 snails per 41 are significantly lower than those of snails at other densities. The possible causation and adaptive significance of these effects are discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Studies on the chemical ecology of Biomphalaria glabrata: The effects of chemical conditioning by the snails kept at various densities on their growth and metabolism

1975

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“…Vernon (1995) suggested that an absence of social facilitation, caused by deprivation of social communication as a result of isolation, may play a role in reducing reproductive output of isolated B. glabrata although the substance(s) that are responsible for this observation are not known. Basommatophoran freshwater snails may release communication substances in the water that may influence feeding, growth, metabolism and reproduction in conspecifics (Ritchie et al, 1966;Thomas et al, 1974Thomas et al, , 1975. Individuals of B. glabrata are thought to be receptive to even very low concentrations of chemicals that are released by nearby conspecifics but the exact nature of these communication substances is not yet known.…”

Section: Social Facilitationmentioning

confidence: 99%

Effects of mating, breeding system and parasites on reproduction in hermaphrodites: pulmonate gastropods (Mollusca)

2007

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There are approximately 20 000 pulmonate gastropod species that are all hermaphroditic and (with a few exceptions) can act in both (i.e., male and female) sexual roles. Life history traits such as growth (rate), age at first reproduction, fecundity, fertility, future survival and offspring survival are highly variable within pulmonate species, even among individuals of the same population. Here, we review some aspects of reproduction (availability of partners, size-dependent sex allocation, courtship, (multiple) mating, sperm longevity/viability, social facilitation), breeding system (selffertilisation, outcrossing or mixed) and parasitism that may influence an individual's reproductive success and therefore account for part of the intraspecific variation in life history traits. A literature study showed that fecundity, fertility and/or growth are significantly affected by: i) the mating group size through changes in interference competition (e.g., crowding), breeding system and sex allocation; ii) individual body size with larger individuals producing more eggs than smaller individuals; iii) mating whereby female fitness may be positively or negatively affected; iv) social facilitation whereby female fitness is positively affected by the presence of conspecifics; v) the breeding system including the phenomena of inbreeding and outbreeding depression; and vi) parasites that may suppress or stimulate reproduction, especially egg-laying, in parasitised individuals. Moreover, multiple mating and multiple paternity seem very common in pulmonates. Interestingly, several of the above-mentioned aspects seem to interact or even act synergetically. Although many aspects of life history variation in pulmonate gastropods are still poorly understood which makes it difficult to draw general conclusions, pulmonates offer ample opportunities to study the evolution of major topics in evolution and life history strategies. Indeed, there is a growing number of basommatophoran and stylommatophoran model species, experimental setups and molecular, histological and histochemical techniques that are used to test current hypothesis on sex allocation, sexual selection (sexual conflict, sperm competition or cryptic female choice), the evolution of breeding systems and host-parasite interactions which will yield much information for the study of life history strategies as well.

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“…Growth rates decline after egg laying and are inversely proportional to oviposition rates ( P. canaliculata ; Albrecht et al ., ). Apart from direct competition for limited food resources, lower growth rates under crowded conditions may also be due to chemical suppressants, including growth suppressive chemicals such as occur in slime trails of other aquatic snails (Berrie & Visser, ; Thomas et al ., , ). The possibility that suppressive chemicals may determine apple snail growth and development in paddy fields has received little research attention.…”

Section: Density Dependence and Intraspecific Competitionmentioning

confidence: 99%

The ecophysiology of apple snails in rice: implications for crop management and policy

Horgan

2018

Annals of Applied Biology

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This review relates the ecology and physiology of apple snails (Ampullariidae) to their impact on rice-production systems. Two species in particular, Pomacea canaliculata and Pomacea maculata, have been introduced to several rice-growing regions. Flooded rice systems represent a high-quality habitat for these apple snails because of similarities in the environmental conditions (water temperature, salinity, pH, water flow velocity) necessary for both rice production and for snail survival and development. Furthermore, amphibious respiration, a capacity to aestivate during dry periods, as well as cold acclimation and tolerance (particularly in P. canaliculata), increases the resilience of apple snails to rice farming practices, including agrochemical applications, intermittent drainage and crop rotations -under a wide range of climatic conditions. Risks to regional rice production depend on four principal factors: these are (a) regional climate, (b) regional rice-production systems, (c) prevailing production practices, and (4) the presence/absence of invasive, non-native apple snails. Based on these criteria, lowland irrigated rice in tropical and subtropical regions that is wet-direct seeded is most vulnerable to damage from both native and non-native apple snails (albeit with greater losses from non-native snails because of normally higher densities). Adequate quarantine regulations, particularly in vulnerable tropical regions that are adjacent to centres of recent outbreaks (e.g. India and Bangladesh adjacent to Myanmar, Peru and Colombia adjacent to Ecuador) and attention to the preparedness of farming systems could reduce potential impacts as these highly invasive snails continue to spread. The urgent development of labour-saving crop-establishment methods that reduce dependencies on chemical molluscicides is necessary to achieve sustainable rice production in regions at risk from non-native apple snails.

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Chemical conditioning of the environment by the freshwater pulmonate snails (Biomphalaria glabrata) and its effect on growth and natality rates

Cited by 12 publications

References 11 publications

Studies on the chemical ecology of Biomphalaria glabrata: The effects of chemical conditioning by the snails kept at various densities on their growth and metabolism

Studies on the chemical ecology of Biomphalaria glabrata: The effects of chemical conditioning by the snails kept at various densities on their growth and metabolism

Effects of mating, breeding system and parasites on reproduction in hermaphrodites: pulmonate gastropods (Mollusca)

The ecophysiology of apple snails in rice: implications for crop management and policy

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