Field Notes: A commensalism friendship

Glenlude Conservation Officer Ellie Oakley looks into an unusual friendship she spotted while surveying adders.

^ The brown female adder with a heather beetle

With this amazing warm weather, we have been busy surveying adders at our Glenlude site in the Scottish Borders.

A few weeks ago, we spotted a female adder with several brown/green beetles resting on her. As I hadn’t seen this before and didn’t recognise the beetle I did some research back in the office.

We guessed it was a heather beetle but were unsure as they are not seen very often as they are far too busy munching away and living its life happily in the thick dense heather.

I got in touch with ARC (Amphibian and Reptile Conservation) to double check it was identified correctly, and to ask why they might be on the adder?

We were right, it was a heather beetle. This is no surprise as they can be found in the same habitats, particularly heathlands and moorlands where heather is abundant.

One of the reasons why they might be on the adder is because heather beetles are far more sensitive to temperature and do not usually emerge in temperatures below 9 degrees celsius. With the adder spending all morning in full sun, she was lovely and toasty for a heather beetle to sit using her like a hot water bottle, heating themselves up.

^ A grey with black zig-zag male adder.