butterfly prenatal development

[John Snyder]

Jim at gpnc.org writes:
>Or is there some
>unformed pre-larva in butterfly eggs that has to finish developing before
>it
>hatches? 

>>>>Let's get technical here (pardon to biologists).  An egg is the gamete
that the female produces, before the sperm fertilizes it.  Upon
fertilization, the "egg" is now a zygote (still single-celled).  Sooner or
later, it undergoes repeated cell divisions, followed by cell movements. 
At this early stage of development the new organism can be called an
embryo, but its cellular arrangements don't closely resemble a larva.  One
could indeed call it a "pre-larva."  Gradually, the cells interact, become
differented into functional cells of many types, and continue movements
until the form of a larva becomes apparent.  It is still within the shell
of the original egg, and looks outwardly like the original egg.  But it is
at this point a pre-emergent larva.

Here's where my expertise wanes.  I suspect, but don't know, that among
those tens of thousands of lep species, there are all varieties as to how
far along the embryo has come toward being a larva when the female
deposits it.  Using the fruit fly as a possible model, it is entirely
conceivable (pardon the pun) that all or  much of the embryonic cell
movements and changes can occur after deposition--fruit fly "eggs" go
through all of the pre-larval changes after the mom lays them, and all
within just a few days until the larva hatches.


John Snyder
Dept. of Biology
Furman University
Greenville, SC USA



 
 ------------------------------------------------------------ 

   For subscription and related information about LEPS-L visit:

   http://www.peabody.yale.edu/other/lepsl