'There are a lot of parallels between the discus fish's parental care and the parental care that we see in mammals and birds,' says Buckley. Initially the parents invest all of their effort in raising their current batch of young, but wean the offspring when their investment in the current brood might begin affecting later broods. Buckley suspects that he sees signs of the conflict often seen between mammals and their young where parents want to wean their offspring and the offspring continue pursuing them in the fish's chasing behaviour during the third week after hatching.
Monitoring the composition of the parents' mucus before they spawned and through to the end of their parental responsibilities, Buckley found a huge increase in the mucus's antibody and protein levels when the parents laid their eggs, similar to the changes seen in mammalian milk around the time of birth. The protein and antibody levels remained high until the third week and returned to pre-spawning levels during the fourth week after hatching. Buckley suspects that the sudden increase in protein levels at spawning is hormonally regulated, much like the changes in mammalian milk, and is keen to find out more about the hormones that regulate the fish's mucus supply as they care for their young.
|Contact: Kathryn Knight|
The Company of Biologists