cecropia larvae

Kurt Jacobs morphidae at earthlink.net
Tue Jun 20 02:15:54 EDT 2000

"Lisa Larson" wrote

> > There was some murky liquid around them which they may have exuded while
> dying, or may have drowned in.  The leaves I put in last >night were a
little damp from rain--

It is a great idea to always wash the leaves you give you silkmoths with
cold water.  It is also very important that the leaves are air dried before
they are put into an enclosed container with H. cecropia.  Putting first and
young second instar larvae into a large glass container is A-OK because the
larvae are gregarious at this age, but the leaves should be taken out a
couple times a day even if signs of condensation are not evident on the
interior surfaces of the container.  The air will also be foul from the
frass.  After the second instar, it is unwise to put larvae in an enclosure
unless it is screened.

Conditions of 100% humidity are not natural for larvae.  They exist in
nature at relative humidity levels of 40-65%(during the daylight).

> Or could some disease have afflicted them, despite their being indoors?

Everyone claims that cecropia is very susceptible to sickness, while
polyphemus is very easy to raise.  I have never had a problem with cecropia,
but have never had a polyphemus make it past the molting into the fourth
instar!  I use box elder (manitoba maple).  As an experiment, I have tried
Norway maple and had 75% death rates and have also tried Red Maple and had
90 % death rates.  I havent tried lilac, but wouldnt think it that great.
My first choice for cecropia would be box elder, and my second choice in a
pinch would also be box elder. I am sure that there exists alot of
disagreement among silkmoth breeders on the choice of hosts.  This is
interesting to me so who would even think of raising luna on anything but
paper birch, and who would attempt raising promethia on anything but hickory
spp.  Sorry I dont have the scientific names of trees handy.  My lack of
success with polyphemus has always been with Oak, as that is what I have
always found them on.

> Or should I just expect this sort of mortality rate?

Expect to lose 10-25% of your stock.  I have so far lost 1% of my 1st Instar
larvae (only rearing 75-100).  They both were dry dead, which tells me that
they died a healthy death!  When your larvae die and leave pools of fluid
around their outer skins, expect a few more problems.  I have seen this
problem with luna, and quick removal of diseased larvae as well as a total
change of rearing containers (screened or totally enclosed) is necessary.

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