Ladybirds…

I opened a window that had been shut for about six months and found a good collection of ladybirds hiding among the carpentry imperfections.

I was struck by the diverse patterns and wanted to explore if they were different stages of development or different varieties. What I need to find was a key or identification guide. I thought that this one from the UK Ladybird Survey would be a good starting point. There may be some differences between the varieties in la Vendée and the UK but I expect there is considerable overlap. What I quickly discovered was the existence of a beetle called the Harlequin ladybird. This is what Wikipedia has to say about it…

Harmonia axyridis is a large coccinellid beetle. Its colour ranges from yellow-orange to black, and the number of spots between none and 22.

Well that’s great! My huge variety of interesting and different beetles are in fact all the same type.

These are beetles native to Asia, introduced to Europe to try to help control aphids in agricultural and horticultural crops. The Independent reports that they are now beginning to be bit of a nuisance in the UK by pushing out the native species to the extent that they are now the most numerous species. They don’t just eat aphids either but have developed a taste for the larvae of lacewings, hover flies and even other ladybirds.

The colour of a ladybird is a good indicator that it will probably not be good to eat. They produce a chemical in their wing casing (elytra) called isopropyl methoxypyrazine which is bad smelling and puts predators off. The Asian invaders have even higher doses of this than the native varieties giving them yet another competitive advantage. The BBC has a nice page about them here.

Harlequin ladybirds can be identified by the fact that they are bigger than most of the native species and by the W or M shaped black marking on their pronotum. The pronotum is the first part of the thorax and is the section just behind the head, to which the first pair of legs attach.

From the UK Ladybird Survey, this diagram shows you a little about the ladybirds life cycle but also when you might be spotting them. Especially go to the Harlequin ladybird pages if you want to help their numbers being monitored.

This is a rather charming (i.e. amateur) video about the harlequin ladybird made in Oxford.

And this is equally charming but perhaps a little less science-based…

.

Questions…

1. What are the three sections of an insect’s body called?
2. Suggest another identifying feature of an insect.
3. What trophic level do ladybirds occupy within the ecosystem?
4. What word describes a period of sleep through winter?
5. What word describes the complete change in body shape over the life cycle of an organism>