This silvery blue butterfly has two broods so can be seen in May and June and again in August and September. Common in gardens, woodlands and hedgerows. Holly Blue Facts: • The Holly Blue is the only British butterfly to produce two broods each of which uses a different primary foodplant; the spring brood uses Holly whereas the summer brood favours Ivy. • Early names for the holly blue included 'Blue Speckt Butterfly' which recognises the pattern of spots found on the underside and 'Wood Blue'. • Holly blue numbers fluctuate wildly thanks to the parasitic ichneumon wasp which lays its eggs in early Holly Blue larvae and adult wasps then emerge from the Holly Blue pupae. As the Holly Blue numbers decline so too do the wasp numbers and thus continues this see-saw effect on both populations.