Brain the size of a ...

I am lucky to live in a large village surrounded by woods and fields and so yesterday I went for a walk with the current Mrs Haffey. It was hot and humid and clearly the insects were loving it. There were lots of greenfly about (I use the term "greenfly" loosely; we're talking about something tiny and green that flies) and it suddenly struck me how astonishing it is that greenfly exists at all.

Somewhere in its tiny brain (and I hope I am not being too rude by describing it in this way) is everything needed for a full existence, if not one which I would regard as complete. I suspect it doesn't have much appreciation of the Arts and its Scientific and Literary achievements are minimal. Yet it leads a full life. It eats out most days, probably every day come to think of it. It gets to fly places, something we humans don't do very well. It reproduces.

All of this is managed with a brain so tiny it weighs a fraction of what just one hair from my head weighs. Now I don't think I am being unduly modest when I tell you that if I cut off a tiny bit of one of my hairs equal in weight to the brain of a greenfly - or even the whole greenfly itself - it wouldn't do much. I may be wrong, but I think the fragment of hair would just lie there.

Isn't nature astonishing?