It was a poor year for the Adonis Blue locally. It was reported from just 4 sites within the Upper Thames area.

Numbers at these sites were lower than usual with only Lardon Chase returning figures that suggest a strong colony.

Adonis Blue
Photo © Nick Bowles

Adonis Blue m.
Photo © Alun & Chrissie March

Amounts of Horseshoe Vetch (the sole foodplant of this species) appeared unchanged at all sites, so it is presumed that the cool, wet weather leading to taller growth of vegetation surrounding the Horseshoe Vetch, directly slowed the development of the immature forms of the butterfly or adversely affected essential interactions with ants.

In this country, larval development requires lengthy exposure to sunlight (resulting in locally higher temperatures) or it is too slow to be completed within the necessary time frame. Tall vegetation creates shade and lowers the temperature below critical thresholds for both butterfly and associated ants.

The 2007 distribution of Adonis Blue (Lysandra bellargus). Records via Levana.

Contact has been maintained at all key sites and regular surveys conducted.