Dear Patty,

Your question is a good one, in which I have long been interested.
In the course of evolution of cone shells, a number of them attained the
ability to subdue fishes by means of venom apparatus and other tactics
that enabled the slow animals to consume more agile prey. The big
question is whether or not the juvenile cone shells, just after settlement
and metamorphosis, can find and eat very small fishes. Most very small
fishes are in the planktonic life and hard to find them on the coral reefs.
The larval cone shells (veligers) are most likely plankton-feeding and
would consume phytoplankton as there is no veligers known to eat
animal or zooplankton. I have not got the book by Alan Kohn and his
colleague on the larval development of Conus, but there may be very
few species of Conus that were reared from veligers to settlement.
(Those juveniles that crawl away from egg cases are easy to raise.)
I kept several Conus geographus in my aquarium in hope of getting them
to spawn, but failed to get any egg mass. I really wish to find out the
first juvenile food for any piscivorous cone shells. Perhaps, the early
juvenile might eat something else than very small fish that may not
be available at right size at right time. I suspect, because of the
general tendency of conservatism in larval stages of many marine
invertebrates, the juvenile Conus would be about a few millimeter
or less in length at settlement. The largest settlement size for marine
gastropods from pelagic veligers (not crawl away juveniles) is less than
five millimeters. The smallest fish (even juveniles of smaller species)
may be much larger than the early juvenile cone shells that needed
the first meal to establish themselves on the reef flat.

When I discovered that the juvenile crown-of-thorns starfish ate encrusting
coralline algae just after settlement, it was a good surprise to those who
assumed that the juvenile starfish ate corals from the beginning of sedentary
life. The juvenile starfish was too small to attack coral polyps, and coral
polyps could easily kill the small juvenile starfish of less than a millimeter.
The evolution of unique feeding habits may need substantial preparation
through the development of appropriate system.

Masashi Yamaguchi
e-mail: [log in to unmask]
Faculty of Science,
Univ. of the Ryukyus


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From:  Patty Jansen [SMTP:[log in to unmask]]
Sent:  Sunday, August 13, 2000 15:37
To:  [log in to unmask]
Subject:  Conus geographus questions

Dear all,

In light of Guido's request, and responses pointing the finger at
pharmaceutical companies, I was wondering if anyone has ever successfully
bred this species (or any other cone for that matter) in captivity. And how
old is a mature shell?

Patty

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