The Holly and the Ivy.... and the Holly Blue

Holly Blue Butterfly, Celastrina argiolus

The Holly Blue butterfly (Celastrina argiolus) is on the wing at this time of the year, its delicate blue colour gracing holly trees where females will lay their eggs. This activity explains their common name, Holly Blue, but is something of a misnomer. C. argiolus is a polyphagous insect, one of the only true polyphagous butterflies in Britain and Ireland (1), and in North America (where it is called the Spring Azure) it is associated with an entirely different set of plants (2). At this time of the year, holly is certainly its preferred choice in this part of the world. It will however produce a second brood from August to September and it then will lay its eggs on ivy plants (3). The popularity of both these host plants in urban habitats has lead to C. argiolus adapting well to city environments (1).

Holly Blue Butterfly, Celastrina argiolus

References:

1. Dennis, 2010. A Resource Based Habitat View for Conservation: Butterflies in the British Landscape pp. 23, 231
2. Pyle, 2007. Sky time in Gray's River: living for keeps in a forgotten place p. 112
3. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 108