The form of Pumice that I referred to is a crushed, natural-occurring form
of the stone. The particles are pulverized until a size of about 4mm is
achieved. This process results in several different-sized,
irregular-shaped particles. When these particles are piled into a plastic
container for incubation, they are by far more superior than vermiculite.
I say this in accordance with my experience. The quality of each of these
two mediums is quite different. When Diplodactyline eggs are half-buried
in the crushed pumice stone they apparently are in a better position for
gas exchanges (water, 02, C02). Eggs incubating within 100% vermiculite
are subject to radically changing moisture/humidity levels, and the gas
exchange is also impaired. When the pumice stone is utilized, moisture
present at lower levels (sometimes perhaps a half-inch below the eggs) in
the container seem sufficient for proper development. In this manner the
eggs are not directly in contact with moisture, thereby eliminating the
possible liquid membrane that would encompass the lower 50% of the egg
lying in straight moist vermiculite (which may interfere with gas
exchanges, or inconsistent moisture absorption). This is already well
understood by attentive Phelsuma keepers.
I learned several years ago about the problems associated with vermiculite.
I had several full-term rare gecko babies die in the egg. Many of these
babies appeared bloated - a condition perhaps aggravated by excessive
moisture which may have caused any of the following: excessive pressure
within the egg on the developing embryo, a general deterioration of the egg
tooth - due to prolonged exposure to excessive moisture (this may also be
caused by improper supplementing), the inability to pip the egg due to
excessive moisture/pressure between the embryo and the egg-shell, and so
forth. Basically, I have completely eliminated vermiculite from my
husbandry practices and have never looked back. I don't miss the product,
nor do my improving hatch percentages. In the span of time that I have
bred geckos, many things have evolved including the knowledge of the
keepers and their ensuing success', products, terrariums, literature, and
certainly the proper selections of incubation mediums. It is quite tragic
to allow animals to pass through important breeding seasons while watching
neonates drown from excessive moisture absorption. Sometimes these one or
two year periods may well be the most important cycles the animals will
live through (reproductively).
Lastly, it is difficult for me to make generalizations regarding this topic
within a reasonable read for most other list members. In reality, there
are several factors which contribute to the proper chain of events. Any
weak link in this chain may ultimately alter the strength of a person's
husbandry successes. Starting of course with proper mediums.
Despite all of my rambling above, the evolution continues. I feel there
are further superior mediums to the pumice stone.
These I am already using with even better success, but this period has been
rather brief (about one year). Perhaps after another year or two of
experience I may better support my statement regarding it (seramis,
seramis/charcoal). Fortunately, I have seen improved success with both
hard-shelled eggs, and soft-shelled eggs with the use of seramis.
Jon
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