Fish cocoons block biting bugs

摘要

The mucus cocoons in which some fish sleep seem to protect them from attacks by parasitic invertebrates.rnAlexandra Grutter at the University of Queensland in Brisbane, Australia, and her colleagues placed coral-reef parrotfish (Chlorurus sordidus) in bins of water with parasitic gnathiid isopods overnight. They found that only 10% offish in cocoons were attacked by the parasites, compared with 94.4% offish that had been teased out of their shelters.rnSecreting the mucus to prevent parasite attacks - a mechanism thought to be unique to these fish - costs around 2.5% of a fish's daily energy budget, the researchers calculate.