Sub-species, forms and their caterpillars question

[Dave McCormick]

I just wondered something. You know the way there is sub-species of butterflies and forms? Are the early stages of the sub-species or forms any different from the main species eggs/caterpillars/pupae itself?

[Piers]

Hi Dave,

A subspecies is a clearly defined taxonomic division where characteristics that serve to make the subspecies differ from the nominate form are derived from changes that have taken place or evolved as a result of geographical distribution or isolation of the subspecies from the nominate form.

A 'form' (in the context of your posting) is a loose term that can refer to a regularly occurring genetic aberation, a seasonal dimorphism (the spring/summer forms of the wood white) or when a species exhibits sexual dimorphism (clouded yellow for example - form helice)

Certain subspecies have larvae that do behave in a manner that is distinctly different from type; for example different larval food plant, or perhaps a different colouration, both of which would have occurred through evolution to suite the habitat and environment in which the subspecies lives.

Certain larvae and pupae exhibit different forms, for example the pre hibernation 'waxy' form of certain pierid pupae (to aid successful over wintering), and the seemingly random different colour forms of the large heath pupae, or the many different colour forms of holly blue larvae.

Felix.

[Neil Hulme]

Hi Dave,
Felix is spot on with his explanation. But to complicate matters even further, it is also possible to get variation (in these cases most likely environmentally- rather than genetically-influenced) in the early life-cycle stages, that are NOT later manifested (visibly) in the adult. This can be seen for instance in the wildly different colouration of, for instance, Hawkmoth caterpillars. The Convolvulus Hawk most often has bright green larvae, but sometimes they are pitch black with brown markings! The adult moth will look the same though.
Neil