chrysalis adaptive colouration

Stephen Hall s_k_hall at
Wed Aug 19 05:19:18 EDT 1998

It has long been known that the pupae, particularly those in the
Papilionidae family (eg., Papilio)  appear to be able to adopt a colour at
the time of pupation, dependent on the surrounding colour - for example, if
the larva pupates on a dead twig the pupa tends to be brown; if the larva
of the same species happens to pupate on a leaf, it tends to be green. I
have pupae of a Madagascan swallowtail, Papilio epiphorbas, in front of me
at the moment, and in addition to the common green and brown forms there
are white, yellow, lilac ones, and some with mixture of colours. This
adaptive colouration in pupae is common in the butterfly world, though in
nymphalid pupae the variety of colours may be limited to shades. I also
have pupae of Phoebis sennae here, most of which are green but two pupae
found off the foodplant are a beautiful rosy pink colour! Many theories
have been presented to attempt to explain this, from Chemical Stimulus, CO2
concentration or humidity, to natural selection. One of the latest papers
on this subject (Hazel, 1995) discusses environmental, neuroendocrine and
genetic factors and although its rather heavy going it provides an
excellent source of other references. This is a very complex topic and each
has its own valid arguments, but it seems that every other paper
contradicts what previous author has stated - its all very confusing.

Recommend anyone interested to read:
*****Hazel, W. 1995. The causes and evolution of phenotypic plasticity in
pupal color in Swallowtail butterflies. p.205-210 In: Scriber, J. M.,
Tsubaki, Y. & Lederhouse, R. C. [eds.], Swallowtail Butterflies: Their
Ecology and Evolutionary Biology. Gainsville, Scientific Publ.


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