We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Factors affecting the predation of Marisa cornuarietis on Bulinus (B.) truncatus, Biomphalaria alexandrina and Lymnaea caillaudi.
- Authors
Demian, Emile S.; Lutfy, Ramsis G.
- Abstract
1. The rate at which adult individuals of Marisa cornuarietis prey on adult and juvenile Bulinus truncatus and Lymnaea caillaudi increases with temperature up to about 30°C, then decreases slightly again. 2. This predatory activity normally decreases to some extent in presence of abundant vegetable material edible to the predators. 3. It seems that adult Marisa, while preying on Bulinus and Lymnaea, develop a certain progressive predatory habit, and that with the development of such habitual predation their attack on both these snails becomes less affected by the presence of vegetable food. 4. The rate of predation is more or less directly proportional to the ratio of predators to prey, and is far less affected by population densities. 5. Adult and juvenile Marisa are capable of preying freely on newly hatched individuals of Bulinus, Biomphalaria alexandrina and Lymnaea. There is strong evidence that Marisa ingest whole such very small individuals. With larger specimens, they attack only the soft parts. In the case of Biomphalaria, however, Marisa can only devour small specimens with shell diamater less than 5 mm. 6. Adult Marisa are capable of consuming the egg-masses of the three vector snails investigated and with a greater voracity than do newly hatched and juvenile individuals of Marisa. 7. The predation of Marisa of all ages on the egg-masses and newly hatched individuals of Bulinus, Biomphalaria and Lymnaea does not take place only accidentally while the predators are browsing and feeding on aquatic plants, but also deliberately. 8. It seems probable that Marisa of all ages are capable of reducing considerably Bulinus, Biomphalaria and Lymnaea populations.
- Subjects
PREDATION; MARISA cornuarietis; BULINUS; LYMNAEA; PREDATORY animals; AQUATIC plants; AQUATIC ecology; AQUATIC biology
- Publication
Oikos, 1966, Vol 17, Issue 2, p212
- ISSN
0030-1299
- Publication type
Article
- DOI
10.2307/3564945