Harlequin Ladybird?

Sorry if this has already been discussed, but today I was out about about in the garden helping my mum when I spotted loads and loads of bugs that look like this all over the leaves of a particular tree.
My mum wanted to spray something (read: anything, just to make her feel better ) all over the poor tree to kill them. I told her to hold off, in case they were good bugs.
I've subsequently discovered that actually they are far from it, as I'm 99% sure they are so-called 'harlequin ladybirds'.
How should we deal with this infestation, as the leaves on the tree are going quite yellow, despite the time of year.

Ta. x

 

I see...thanks for the info. I suppose just leave it then as there do seem to be an awful lot of the things!
Thanks for putting my mind at rest :D

 

Can you tell if its a harlequin from looking at the larvae ?

I'd leave it alone.

 

Well I'm pretty sure I've identified them correctly after Googling them and finding pictures of critters that look the same. I think I'll advise Mum to leave them alone.
Aside from eating bugs that might actually do our garden good - do they do any other kind of damage that we should be worried about?

 

Armandii, thats been going on since Roman times, (probably before), in one way or another.
We dont stand still and neither does nature.

But I'm sure some conservationist would like it to.

 

Surely we should just let nature do her thing...don't we mess things up enough? haha