Disease in Cecropia larvae????

Rob & Ryan lepidopterists at home.com
Sun Aug 13 11:20:29 EDT 2000

Emily, here is a posting from my son Ryan from a while back regarding the
sudden demise of larva. One ever increasing culprit is the below mentioned
nuclear polyhedrosis virus. This may be true in your case, However you
mentioned your larva were very small for the later instars they are in.
Normally the polyhedrosis virus will not affect larva in this fashion but
infect and kill it quickly. Your current food source may be contaminated?
    Hope this helps out.

    Hey there everyone. In our many years of larva rearing occasionally we
run into a situation where all or most of our larva would be healthy one
minute and the next day be deflated bags of mush. We have always accounted
this to a spider or some such vermin escaping our watchful eyes and
feasting on our specimens. Only within the last year have we learnt of a
virus called the nuclear polyhedrosis virus. This virus is a major player in
the sharp rise and fall of tent moth populations. Although can effect most
any larva. the following is an exert from Chapter 7 of "British Columbia, A
Natural History" by Richard and Sydney Cannings.

Viral bodies on leaves that in turn are eaten by the caterpillar and
replicate in the nuclei of the larva's cells. Within a week or so millions
of viral bodies are produced and the caterpillar bursts, leaving a limp
cadaver on the leaf and a huge number of viral bodies to spread the disease
to other caterpillars. when  most of the caterpillars are dead the viral
bodies have very few hosts in which to replicate and outside their hosts,
the viral bodies are slowly destroyed by ultraviolet light.

Happy Collecting,
Robert & Ryan Vandermoor, B.C. Canada.


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