By Vida, volunteer photographer
A couple of weeks ago I was out in the walled garden of Fulham Palace with my macro lens, tracking a beautifully vibrant, giant pink larkspur (delphinium), when a flash of silver-blue caught my eye. High up on the stems, a delicate little holly blue butterfly (Celastrina argiolus) was flitting restlessly. She would land briefly on a cluster of flower buds, take off and repeat the dance before finally settling down.
I snapped a quick series of macro shots, but it wasn’t until I got home and zoomed in on my computer that the real magic revealed itself. There she was, with her abdomen tightly curled under, carefully cementing a single microscopic egg right at the base of a plump larkspur bud!
The holly and the ivy (the usual rules):
If you look up the holly blue on authoritative sites like Butterfly Conservation, you’ll find they are famous for a very specific, strict seasonal menu:
The Spring generation: Females almost exclusively seek out holly (Ilex aquifolium), placing eggs on the young spring flower buds.
The Summer generation: The next brood hatches and switches entirely to ivy (Hedera helix), utilising late-summer ivy flower buds.
This strategy allows the species to maximise the survival of it’s two distinct annual generations.
While they are known to occasionally break the rules for other shrubs like dogwood, spindle, or Portuguese laurel, seeing a holly blue opt for a herbaceous garden perennial like a pink larkspur is an incredibly lucky, non-textbook moment. The caterpillar that should have hatched around four days later would have a very gourmet, pastel-pink start to life!
