Monday, 8 June 2015

Day 217 - Terrific Tansy Beetles

Tansy Beetle ( Chrysolina graminis)
Hi all today's Day 217 and yesterday I went out on a walk/bug watch at York. Now these weren't just any kind of Beetle, they were endangered beetles. Besides these amazing beetles, it was a great walk through that I think is one of York's nicest natural places called Rawcliffe Meadows. It's a very hidden away place with the Cycle Route 65 running through it which I do intend to ride sometime. Now these endangered beetles are the iridescent Tansy Beetle.

So, here are the facts:
  • Their population varies quite a lot as in 2012 their population was but 2,000 but last year their population was about 21,000.
    Meeting a Tansy Beetle Head on!
  • This is due to flood events happening a lot seeing as they live near rivers. If you live in the UK, you'll know that 2012 was the year with the Summer Floods but this year it seems to be gloriously sunny :-?
  • Now, you're probably thinking '21,000! Why are they an endangered species then?' well it's because there are only two places where they're found. A single summer flood along the Ouse could wipe out nearly the entire UK population. A 45km stretch of the river Ouse around Yorks is their main home. 
  • There is a very small population on a Fen in Cambridgeshire where a few individual beetles were found in 2014 for the first time in forty years. If it wasn't for this find they would be Critically Endangered.
  • I said above that a Summer flood could severely affect them. They do happen on th OUse but not as often as winter floods. It seems they don't mind winter floods when they have buried themselves in the ground and are hibernating.
  • Why don't they just fly to safety? Well this is linked to their life cycle. Adults emerge from the soil in around April and feed and mate. Eggs are laid and hatch around May to July. The larvae then feed up and when large enough burrow into the soil to pupate.
  • If the larvae get flooded they don't survive. New Adults emerge around mid July. The new adults have well developed wings and flight muscles and could fly away. The trouble comes when they hibernate and their flight muscles waste away. So if the flood is at the wrong time of the year for the beetles they could be in big trouble!
Eggs which are laid upright on the leaves
  • As you can see they are an iridescent beetle and you are probably wondering why. It's probably a bit of a defence mechanism. A recent study which had a quail pecking at normal green beetles and then iridescent beetles on a computer screen. It took the quails longer to peck at the iridescent beetles and they were less accurate. So the iridescence may confuse predators!
  • You've probably guessed this but they are called Tansy Beetles as they only feed on Tansy, an aromatic plant that is found in good numbers along this bit of the Ouse.
  • Plants have to be quite close together to support a population as it seems they will only walk 150m at most to find a plant.
Tansy Beetles live life on the edge!
  • A group (with a brilliant acronym) the Tansy Beetle Action Group is looking at ways of helping the beetle. This group is made up of lots of organisations and people that do different things like growing and planting Tansy, breeding the beetles for re-introduction on suitable sites etc. 
  • They are not doing well and spreading as changes in land use and invasive species such as Himalayan Balsam are reducing their habitat and food plant.
Well, most of the above I have to thank Dr Geoff Oxford for as he led a talk on the meadows all about the Tansy beetle. (thanks again Geoff). However if you want to find out a bit more try these sites.

Bug Life - Tansy Beetle & TBAG

Friends of Rawcliffe Meadows - TBAG

North Yorkshire County Council - Tansy Beetle

Hope you enjoyed,



  1. Amazing beetles Zach, I love that bright shade of green! - Tasha

    1. They really are great Tasha, the meadows were amazing too!