Brown argus

A long, hot day of fieldwork, followed by a visit to Sainsbury's to stock our almost bare cupboards has pretty much wiped me out! I should have taken the dogs out for a walk this evening, but I'm afraid I fell asleep instead....Luckily they're very forgiving and I've promised them an extra special walk tomorrow morning, when it's nice and cool.

So one again it's a photograph snatched while working. This is a brown argus Aricia agestis, the most frequent butterfly seen today. In the field this butterfly can be recognised by it's neat brown appearance, though ideally the pattern of spots on the underside of the wing should be checked, to ensure it's not mistaken for a female common blue, which also has brownish wings, but always has at least a dusting of blue scales at the base. In female common blues the black mark on the forewing is also much less distinct.

Interestingly, to the naked eye this butterfly looked completely brown, but the camera has detected a bluish iridescence. This is a common phenomenon, especially in strong sunlight, and can make identification even more confusing! But although it has a bluish sheen, there are no blue scales.

This is a warmth-loving species and, as such, is often found in sheltered areas or on south-facing slopes, where it forms discrete colonies that don't move more than a few hundred metres. It thrives on brownfield sites, where the larvae eat dove's-foot crane's-bill or common stork's-bill, both of which were plentiful at the site. Like most blues, the larvae are attended by ants, which helps to protect them from predators.

One of the reasons I took this was to try out the macro-possibilities of my new lens, bought to replace the broken kit lens. I was pleasantly surprised considering I bought it mostly for landscape and general site photography. My monitoring photographs certainly show a lot more detail now!