Holly Blue (Celastrina argiolus)

Male. (The thin black border to the forewing distinguishes the sexes).
Male. (The thin black border to the forewing distinguishes the sexes).
1st-brood female. (The black border is slightly wider in the 2nd-brood).
1st-brood female. (The black border is slightly wider in the 2nd-brood).
Spring-time courting (male on the left)
Spring-time courting (male on the left)
2nd-brood female
2nd-brood female
Underside. (This individual is taking in fluids from fresh horse manure!)
Underside. (This individual is taking in fluids from fresh horse manure!)
Female laying on pyracantha
Female laying on pyracantha
 
Information

NERC Act S41: Not listed
Local status: Common. Widespread across the county.
Numbers rise and fall with a period of about 3-5 years as a result of the parasitic wasp Listrodomus nycthemrus which almost wipes out the species, and itself with it. Both species subsequently recover to repeat the cycle.
Size: Small.
Larval foodplant: Mainly Holly and Ivy, but may also use Dogwood, Spindle, Snowberry and several other shrubs including bramble.
No. of broods: Two
Flight time(s): Early April to Mid June. Early July to mid September.
Winter: Pupa (The only Bedfordshire "blue" that overwinters in this stage).
Habits: Usually seen flying around tall shrubs and trees, often above head height. In summer sometimes seen flying around Ivy in large numbers. Usually rests with wings closed, but may open them in weak sun.
Habitats: Hedgerows, woodlands, churchyards, gardens and parks. This is the "blue" most often seen in urban parks and gardens.
Distribution:

Normalized Weekly Abundance


Flight time graph


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