Holly Blue

Celastrina argiolus


Male, Switzerland, May 2013

Celastrina argiolus

Female, June 2015, Italy

Underside, Switzerland, August 2012

Celastrina argiolus

Male, UK, October 2014

1st brood female, April 2011, Switzerland

2nd brood female, Switzerland, July 2009

2nd brood female, Switzerland, July 2009

Female, Switzerland, July 2009

Female underside, Suffolk, UK, August 2012

Female upperside, Suffolk, UK, August 2012

Female, Suffolk, UK, July 2004 (video frame)

Male, Suffolk, UK, August 2005

Oxford, spring 1987, taking minerals from a bird dropping

The holly blue is a familiar garden sight, even within the boundaries of cities. In fact, I have seen it in some numbers from trains in London, flying over the ivy banks that often straggle near the railsides. Both sexes are unmistakeable once the 'jizz' has been learned. The very white underside, with a washing-powder 'blue-whiteness', colours the insect even in flight, and the upperside too is distinctive, though different in the two sexes. The female always has a very broad dark border to the forewing, broader in the second, summer brood, unlike anything found in any other species. The male, when fresh, shows a broadening of the narrow border near the apex of the wing and also chequering to the margins, but neither of these is visible in worn insects.

In England, the first brood of this butterfly feeds on the fresh, new leaves of holly, while the second brood feeds on ivy. Anywhere (in the south) where both these plants grow you are likely to find holly blues. On the continent, apparently (I learned recently), they are not so regimented and will feed on either plant throughout the season.