Embryonic learning can be
important (apparently) for species that are on their own once they hatch from
the egg. Hatchlings of many species get help with protection, feeding and other
life lessons from one or both parents, but this is not always the case.
Newly hatched turtles have
to make a dash for the sea and learn on the fly. Cuttlefish hatchlings are
already in the sea, but they too are on their own. Romagny et al decided to document the perception and learning of cuttlefish
embryos in the latter stages of development (1,2). They have lots of stages,
but stages 23, 25 and 30 were chosen for them to sit their tests.
Once they get big enough to
flex their mantles, they are showing their ability to respond. They had to be
taken out of their protected egg cases for their test program. They were exposed
to the fishy smell of sea bass. That startled them and they flexed in
consternation as sea bass like to lunch on young, succulent cuttlefish. They
also weren’t very keen on being poked and prodded with a needle, blunt, of
course, but nevertheless they flexed away.
Later on, they were exposed
to light when their visuals were operational, and that too startled them into
flexing. At stage 30, light was becoming a little boring and they would only
bother flexing for a short while before quitting.
The team wondered if they
were just getting tired from overwork so they decided on the willing horse
solution – they spurred them on with a prod from their needle. That got them
working again. They weren’t tired. They had learned that they didn’t need to
respond to the light as nothing else happened. The spur, though, reminded them
that they were supposed to be performing for the team of researchers and they went
back to work with a will.
So it seems that it never
to early to learn which side of your bread is buttered and to mind your p’s and
q’s.
- http://jeb.biologists.org/content/215/23/4125.abstract
- http://jeb.biologists.org/content/215/23/i.2.full
