Date: Sat, 20 May 2000 16:59:28 -0300 From: Vitor Fernandes Oliveira de Miranda <vmiranda@rc.unesp.br> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1601$foo@default> Subject: re: Daphnia- Utric's speculation.
Howard wrote:
> Cast your net lots of times or leave your net out wait for food to
come to > you. You're still need a similar net. Call it
'filtering" or 'trapping' > it just a matter of time perception.
Realize there are difference but we > are talking about structural
design not behavior in acquiring same prey.
Dear Howard,
I guess I could unterstand your point of view. Structural design
of both utrics and water fleas are similar, but there are some
diferences. But you should remember that structural design is
almost always related with behavior. Water fleas, even being
filtering animals, have a predatory habit. It means that they
*catch* your preys, not in a passive way but in a *active* way. It
is not enough to wait for the particles that could be reached for
their antennas, on the other hand the little predator has to bite
the food. Therefore, utrics traps have to wait for a prey that
could *touch* the sensitive hairs, wich so discharge the mouth
opening. Thus, it\\264s difficulty to believe these two organisms
acquired same design in convergence. Researching the utrics traps,
in some analisys that we did with them, we can see several kinds of
glands. I guess some of them has a attraction role, maybe producing
some substances that could attract the prey. Maybe prey specificity
(each utric species seems to catch the same set of preys spp) could
collaborate this idea. Therefore, it is just a particular
speculation.
Regards.
Vitor.
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