How water fleas detect predators

Water fleas of the genus Daphnia detect via chemical substances if their predators, namely Chaoborus larvae, are hunting in their vicinity. If so, they generate defenses that make them more difficult to consume. The signalling molecules that enable detection have been identified by biologists and chemists. It is a cocktail of substances that occurs during digestive processes of Chaoborus larvae.

from Top Environment News -- ScienceDaily https://ift.tt/2PUD342