White-legged Damselfly (Platycnemis pennipes).

A recent and most unexpected find during one of my butterfly transect walks through the ancient woodland pasture on Ashtead Common was the White-legged Damselfly (Platycnemis pennipes).

This medium sized damselfly is described as favouring unshaded, muddy, slow-flowing waters with abundant emergent and floating vegetation but only rarely in lakes and ponds although evidence suggests it is increasingly being recorded at standing waters.

 

Whilst I have walked this area for many years this is only my second year of recording the wildlife, specifically butterflies, throughout this northern section of Ashtead Common to assist the City of London who own and manage the common.

I don't believe I have been any less observant in the past but my first sighting of the White-legged Damselfly was on 11 June this year.

All my sightings since then have all been within 100 yards of the clay-coloured standing waters of Flag Pond, with no inlet or outlet streams, which was probably a former clay pit associated with the nearby site of the Roman villa, bath house and tile works.

The distinctive field characteristics are the thorax markings and that they differ from all other blue damselflies in having expanded white edges to the tibiae plus pale chestnut wing-spots.

My first record shot (left) on a cloudy morning was either a teneral or an immature female resting quite some distance from any water.

The immature female develops from the creamy-white 'lactea' phase, as seen above, into pale yellow-green mature individuals (see below).

The immature male (see above) also goes through a colour change as it matures with black markings on blue, often pale and sometimes green on the thorax. I will be on the lookout for some fully mature males in the next few weeks.