Who ate the dock?

I like a mystery to solve! Yesterday at Parke I saw a dock leaf which had been almost completely eaten – only the veins on the leaf remained. I’ve seen such leaves before but had never given them much thought as to who the culprit might be. Yesterday I decided to investigate.

The leaf in question

A close up

I turned the leaf over and found this – initially I thought it was a caterpillar but upon closer inspection I concluded it was a beetle larvae

Then I spotted and few more larvae

And finally on an uneaten leaf I found lots and lots!

Google is a wonderful tool “Black beetle larvae on dock” provided the answer immediately. These are the larvae of a chrysomelid beetle known as the green dock beetle or Gastrophysa viridula – here is a link with more details of the beast. It is a small (4-7mm) metallic green beetle which totally relies on eating dock as a larvae to complete its life cycle.

Despite searching I couldn’t find any adult beetles – it would seem that they have long left the scene of the crime – see the earlier link  for photos of the adult.

It is a common species found throughout the British Isles – here is the map from the National Biodiversity Network

Always satisfying to solve a mystery.