Sean O'Grady: These ladybirds are bugging me

This is one of the moral dilemmas unleashed by climate change

The Snows of Kilimanjaro are melting. The Ganges is drying up. El Niño is unleashing freak weather all over the world. And, in my tiny corner of suburbia, I've been invaded by ladybirds, a small, colourful but puzzling consequence of climate change.

At least I assume it is. The little beetles wandering around my flat in disturbingly large numbers are definitely ladybirds, but I'm not sure which ones. I suspect they are the new non-native species, the harlequin ladybird, which is supposed to be bigger, tougher and generally more inclined to hang out with you indoors than our proper home-grown types.

Climate change has apparently encouraged them to migrate from southern Europe to my home in southern London, and further north as far as Leeds. The harlequin ladybird is bullying and out-competing our smaller ladybirds.

I say I'm not sure about which type of ladybird is trundling around the flat because I went on Wikipedia to find out (when do I not?) and ended up very confused indeed (when do I not?). So it could be that I'm in fact sharing my home with Nick Griffin-friendly, native ladybirds of the type that have lived on these islands for 17,000 years or whatever the BNP thinks qualifies you to be British.

Anyway, the ladybirds present me with a moral and practical dilemma, and I don't know who to turn to, even if I can successfully classify them. Should I kill them? There is, as far as I know, no Royal Society for the Prevention of Cruelty to Insects. It's not big enough for The Moral Maze, and I don't fancy troubling the priest for advice. Being an animal-loving type (who cannot vote Tory because of they'd bring back fox-hunting, as well as rickets and TB), I don't really want to go around squashing these pretty little creatures that, as The Hitchhiker's Guide might have had it, are mostly harmless to humans and their property. I was brought up to believe that ladybirds are our friends, keeping the greenfly down and beautifying our gardens.

On the other hand, I don't actually ask the harlequins in and they don't make a great pet. They are also evidently not that harmless to our 46 native varieties of ladybird. Things get more morally complex because I'm generally tolerant of culls of alien invasive things that are destroying our settled way of life. Not like Nick Griffin, though, you understand. I'm on about grey squirrels. Hope that's OK with you.

Maybe some readers have experienced a similar infestation, or are philosophically or entomologically trained to offer expert guidance on the issues I face. In the absent of that, I'm inclined to solve this pressing moral dilemma in the usual manner, and ignore it.

The ladybirds aren't causing any bother, and if one turns up in my cereal, and I can distinguish it from a bumper raisin, then I suppose it might get exterminated. But I can't do anything about them invading the nation, and there is a school of thought that holds that taking it out on invasive species is a bit racist. The whole thing is starting to bug me.

s.ogrady@independent.co.uk