Life Habits
The sea butterflies have a peculiar way of feeding. They used to be regarded as passive feeders, but in reality they are active hunters, feeding mostly on plankton but also bacteria, small crustaceans, gastropod larvae, dinoflagellates and diatoms. They entangle their planktonic food through a mucous web that can be up to 5 cm wide, many times larger than themselves. This web is eaten as soon as there is enough food entangled and then a new one is soon deployed. This net also provides them additional buoyancy. If disturbed, they dump the net and flap away. There is a posterior footlobe with cilia, and a pair of lateral footlobes. They transport food, collected by the mucous web, to the mouth.
When they migrate to the surface, they may do so in unbelievably huge numbers. These aggregations usually attract their predators, the sea angels of the genus Clione (family Clionidae, suborder Gymnosomata). They are also on the menu of baleen whales, chunk salmon, pink salmon, herring and certain seabirds.
Read more about this topic: Limacina
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