Slow and steady

Moving slowly through the UK countryside


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Green Tortoise Beetles

Yesterday I found several of these bright green beetles, about 1cm long, on the Hedge Woundwort (Stachys sylvatica) in our garden. The leaves had lots of holes in, which is fine, as although it is a wild flower, it’s a bit of a nuisance in the garden as it spreads by runners. Plus it stinks.

Cassida viridis

Green Tortoise Beetles mating (Cassida viridis)

They are Green Tortoise Beetles, Cassida viridis, distinguishing features being the rounded shape of the back corners of the pronotum (the front shield-like part) and having no red/brown markings, plus living on a plant in the dead-nettle family. The internet is very useful.

On the same plants were small papery brown packages, a few millimetres across. The top layer had bits in that looked a bit like legs…

Green Tortoise Beetle (Cassida viridis)

Mystery egg package

I bravely (or foolishly) investigated. They contained eggs. I wondered whether they were Green Tortoise Beetle eggs, but internet searching only showed up one picture and it was only labelled as ‘likely’ as they hadn’t hatched.

Cassida viridis eggs

Eggs from underneath protective layers

I put a few in a box, to see whether they might hatch out, as the larvae are quite interesting too, covered in spines and camouflaging themselves with excrement. Not everyone would find that interesting, I suppose.

I went out today to see whether I could find any larvae emerging yet, and instead found a female just starting to lay eggs. So I brought her inside and watched for 45 minutes, and took about 70 photos. Yes, I had lots of other things to do, but they didn’t get done.

Cassida viridis egg laying

Green Tortoise Beetle (Cassida viridis) just beginning to lay eggs

After each egg is laid, she goes over the heap and exudes a fluid that seems to instantly dry into a cellophane-like layer.

Cassida viridis oothecum making

Cling-wrapping the eggs

Then, when she has finished, she adds a pool of fluid – and then defecates into it. Whether it is for camouflage, or out of relief after all that hard work, I don’t know.

Green Tortoise Beetle egg-laying

Female Green Tortoise Beetle defecating onto completed egg-mass

I’d read that similar beetles do this, so I was waiting for it… Hmm. So the bits that looked like legs weren’t.

This was about 15 minutes after she’d finished. Clearly the same thing as the ones I found yesterday.

Cassida viridis oothecum

Egg-mass just laid

Well, it was interesting for me. 🙂