The apple snail (in the mollusc family Ampullariidae) is among the Amazon's largest land snails, hence its name, being about the size of an apple. It is aquatic, living in freshwater in shallow slow-moving rivers and ponds, but can survive a short time out of water. It feeds on soft vegetation, but will feed on almost anything including detritus. Predators include fishes, birds, caiman and turtles among other creatures.
Locals consider the apple snail a delicacy and scientists are researching its potential for cultivation by farmers. The species pictured above (most likely a variant of Pomacea canaliculata) is among the most favored.
Most land snails lay their eggs hidden under leaves or in soil where they're safe from predators. For aquatic species such as apple snails, the threat is from fish. This may be why they lay their eggs above the water line. This clutch of eggs (laid by an unidentified species) is attached to the trunk of a tree. When the eggs hatch, the snailings will drop out of the egg and intor the water below. Until the waters rise (due to annual flooding) the eggs will be relatively safe from aquatic predators.