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Nature or nurture?

August 10, 2020

The last blog introduced Nellie and Griff, two young ‘Attenboroughs’ who at our Landcare planting last week spent more time lying prostrate on the ground examining what lived at that level than they did walking around. It raises a very David Attenborough-type question ‘How did they become so interested in this stuff? Is it some inherent quality or did they learn it from the home environment? Nature or nurture?’ It prompted me to find a set of photographs which their mother, Cat, our Landcare facilitator gave me late last year for use in a blog (see below).

Most will associate the insect life-cycle as comprising four distinct stages – egg, larvae, pupa and adult e.g. butterflies. However many insects such as cicadas and dragonflies develop through three phases – the egg, nymph and then the adult. The nymph looks almost identical to the adult (but has no wings) and as it grows it goes through several moults where it casts off the old, small skin (exoskeleton) and develops a new larger one. This process of moulting is known as ecdysis. In the final moult the adult emerges complete with wings.

Cockroaches also develop by this pathway. Cat photographed a cockroach moulting in her wood shed. The emerging insect can be seen backing out of its old skin that is left containing all the features of the recently departed insect including the antennae. The new exoskeleton is initially soft but hardens when exposed to air. From the photo it is hard to tell if the emerged cockroach is the adult or one of the instars (a term used to describe a nymph during the lifecycle e.g. 1st instar, 2nd instar, etc).

And I suspect the answer to the title question is both.

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