chrysalis adaptive coloration

evoluhol at evoluhol at
Tue Aug 18 13:21:59 EDT 1998

As ova and very young larva polyxenes and glaucus are nearly identical.

If the caterpillars fed to maturity on umbrellifers, they quite certainly
are polyxenes as glaucus generally will not survive on them.  As they
matured as caterpillars if each segment was a repeat design of the one
next to it with its black, green, yellow, orange, then they were
polyxenes.  If as they matured they had an enlarged frontal section with
two "eyes" that stare at you then they were glaucus -- and green glaucus
caterpillars usually turn choclate brown as they finish eating and start
to wander.

In many species of lepidoptera there will be wide variation in color and
design, much the same as in adults.  This is evolution and survival at
work.  The environment has been changing since leps appeared on earth, and
will continue to change till after even we humans are gone.  Variations in
design and color on larvae help them keep up with changes particularly in
regards to predation.

As for the green pupa with yellow vs. the brown bark like pupa:
     When I have grown troilus (spice bush), and polyxenes (black
swallowtail) in every case the pupa that are green will emerge the same
summer (resembling leaves and stems) and the ones that are bark like will
     Polyxenes pupae are somewhat elongated and keellike.  As I only have
one generation of glaucus here -- all pupa I have raised are bark like,
quite roundish, but with bits of green down the side like "moss".

Hope this helps,
Dave Bouton

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