Temperature, density and ammonia effects on growth and fecundity of the ramshorn snail (Helisoma anceps)

2017 ◽  
Vol 49 (2) ◽  
pp. 1072-1079 ◽  
Author(s):  
Tien-Chieh Hung ◽  
Troy Stevenson ◽  
Marade Sandford ◽  
Tewdros Ghebremariam
Keyword(s):  
Helisoma Anceps

Intraspecific gastropod shell strength variation among north temperate lakes

1999 ◽  
Vol 56 (9) ◽  
pp. 1687-1695 ◽  
Author(s):  
David Bruce Lewis ◽  
John J Magnuson
Keyword(s):  
Freshwater Snail ◽  
The Body ◽  
Feeding Time ◽  
Strength Increase ◽  
Resource Depression ◽  
North Central ◽  
Helisoma Anceps ◽  
Predator Abundance ◽  
North Temperate Lakes ◽  
Slow Growing

Defensive morphological traits may vary intraspecifically. Freshwater snail shells are conspicuous defensive structures. In north-central Wisconsin, we investigate whether among-lake differences in shell strength relate to water chemistry or predator abundance and whether shell strength is inducible owing to predation risk from crayfish. Amnicola limosa shells were stronger in lakes with abundant crayfish predators. An experiment and a general understanding of prosobranch evolution suggest that this may result from selection rather than induction. The experiment indicated a weakening of shells of slow-growing A. limosa in the presence of crayfish. This may have resulted from resource depression caused by a strong behavioral response that reduced feeding time. Physa skinneri shell strength was correlated with lake calcium concentrations, and a weak trend with calcium was apparent for Helisoma anceps. Decreased P. skinneri shell strength in low-calcium lakes may result from retention of scarce calcium by the body at the expense of allocation to the shell. Populations of H. anceps differed in rates of shell strength increase with body size, suggesting that rates of shell strength accumulation with ontogeny vary among populations. Shell strength increased more rapidly in lakes with abundant predators than in lakes with few predators.

LONG-TERM ANALYSIS OF CHARLIE'S POND: FECUNDITY AND TREMATODE COMMUNITIES OF HELISOMA ANCEPS

2007 ◽  
Vol 93 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
N. J. Negovetich ◽  
G. W. Esch
Keyword(s):  
Helisoma Anceps ◽  
Term Analysis

Distribution of aquatic gastropods across an interface between the Canadian Shield and limestone formations

1972 ◽  
Vol 50 (11) ◽  
pp. 1433-1445 ◽  
Author(s):  
W. B. McKillop ◽  
A. D. Harrison
Keyword(s):  
Natural Waters ◽  
Calcium Concentration ◽  
Individual Growth ◽  
Natural Gradient ◽  
Reverse Pattern ◽  
Physa Gyrina ◽  
Helisoma Anceps ◽  
Individual Growth Rate ◽  
Lake Simcoe

This quantitative study gives a convincing demonstration in situ of the direct relationship which exists between the distribution and density of aquatic gastropods and the calcium concentration of their natural waters. The area chosen, in the Gravenhurst–Barrie district of southern Ontario, north of Lake Simcoe, provided a well-demarcated natural gradient across the interface between limestone formations and the calcium-poor rocks of the Pre-Cambrian Shield. Monthly quantitative samples over a 14-month period at 25 stations showed that most pulmonates, notably Physa gyrina and Helisoma anceps, had high densities in hard and medium water, whereas the prosobranchs Amnicola limosa and Campeloma decisum showed a reverse pattern, with highest densities in soft and medium water and very low densities in hard. Most pulmonates showed a slower individual growth rate in soft water and a lower proportion of large individuals.

A comparison of the life cycles, reproductive ecologies, and size–weight relationships of Helisoma anceps, H. campanulatum, and H. trivolvis (Gastropoda, Planorbidae)

1975 ◽  
Vol 53 (12) ◽  
pp. 1812-1824 ◽  
Author(s):  
Hans Boerger
Keyword(s):  
Life Span ◽  
Life Histories ◽  
Live Weight ◽  
Dry Weight ◽  
Life Cycles ◽  
Spawning Season ◽  
Minimum Size ◽  
Regression Equations ◽  
Shell Weight ◽  
Helisoma Anceps

Helisoma anceps, H. campanulatum, and H. trivolvis were studied separately in three ponds near Waterloo, Ontario, and were found to differ in the following parameters, respectively: life span, 2.1, and 2 years; mean growth rate during the first 2 months after hatching, 0.2, 1.0, and 0.06 mm/week; minimum size at which snails laid eggs, 8, 10, and 18 mm shell diameter; number of breeding periods during the life cycle, 2, 1, and 1: length of the spawning season, 18, 10, and 8 weeks; date by which 50% of the eggs had been laid, July 2, May 14, and May 15; mean number of eggs per egg capsule, 14, 14, and 24. Although mature H. trivolvis occurred throughout the pond during the spawning season, eggs were laid only along the margin. The average number of eggs laid during the life span of a snail was 300 for H. campanulatum and 590 for H. anceps. Linear regression equations relating size to live weight, shell weight, and shell-free dry weight were calculated for each species. Differences between the three species in geographic distribution, tolerance to environmental perturbations, and frequency of congeneric associations seem to be related to differences in their life histories.

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