Armor Up! Water Fleas Grow Helmets and Spines for Battle

Water fleas prepare for battle by growing armor that's customized to specific enemies, new research finds. Now, researcher Linda Weiss of Ruhr-University Bochum in Germany and her colleagues have found the neurotransmitters that help water fleas customize their bodies in response to the chemical cues in their watery environments. Daphnia is a genus comprising many species of the tiny crustaceans known as water fleas.