Physiological aspects of Stagnicola bulimoides techella

Abstract

Several aspects of the metabolism of the lymnaeid snail Stagnicola bulimoides techella were examined. Studies of respiration rates demonstrated the effects of oxygen concentration, age, reproductive status, weight and temperature were each significant. The relationship between respiration rate and weight was not linear. Rates were highest for uninfected snails during early growth and egg production, and were lower at all other times. The respiration rates of snails infected with the trematode Fasciola hepatica were varied and unpredictable. Respiration rates decreased with decreasing oxygen concentration, although snails showed the same apparent activity level at different oxygen concentrations. Parasitized and unparasitized snails maintained underwater without access to air survived as long as parasitized and unparasitized snails maintained with access to air. The parasite developed normally. None of the parasitized snails (regardless of maintenance) and one of the uninfected snails (maintained underwater) produced eggs. All uninfected snails with access to air produced eggs. Both parasitized and unparasitized juvenile snails migrated before aestivating. Fasciola hepatica was able to survive aestivation. A comparison of the caloric content of the tissues of snails during or immediately after oviposition to the tissues of snails two weeks after oviposition showed the differences were not statistically significant.