Holly blue
Celastrina argiolus
Habitat
The Holly blue lives in Ireland and as far away as Japan. This butterfly species is also found in North America and from Scandinavia to North Africa. The Holly blue is found in thickets with spindle trees, wooded areas, gardens, parks, and rural areas. The Holly blue has two generations. The first generation can be admired from mid-April to the end of May. The second generation can be spotted from the beginning of July to the end of August.
Appearance
Life cycle
The Holly blue stays in the egg for 3 to 5 days. When the Holly blue emerges from the egg, this butterfly species is still a caterpillar. The caterpillar lives for 15 to 27 days, after which it pupates. Pupation lasts 11 to 20 days for the first generation and 220 to 230 days for the second generation. The Holly blue will then live as a butterfly for 9 to 18 days.
Host plants and nectar plants
Host plants are special plants on which butterflies, such as the Holly blue, lay their eggs. When the eggs hatch, the caterpillars feed on those plants. The caterpillars grow until they are large and strong enough to transform into butterflies. This is why host plants are essential for the survival of butterfly species, because without host plants there would be no caterpillars and ultimately no butterflies.
Each butterfly species has its own favorite plants. For example, the first generation (caterpillar) of the Holly blue likes to feed on Alder buckthorn (Rhamnus frangula) and Holly (Ilex aquifolium). The second generation feeds on Common ivy (Hedera helix), Butterfly-bush (Buddleja), Common heather (Calluna vulgaris), and Purple loosestrife (Lythrum salicaria). In addition, this butterfly species uses Common dogwood (Cornus sanguinea), Liquorice milkvetch (Astragalus glycyphyllos), Alfalfa (Medicago sativa), European buckthorn (Rhamnus cathartica), Darley Dale heath (Erica darleyensis), Vaccinium (Vaccinium), and Brambles (Rubus) as host plants.
Most butterfly species, such as the Holly blue, need nectar to survive. Butterflies obtain nectar from nectar plants. Nectar is a syrupy liquid that comes from flowers. This liquid contains a lot of sugar, small amounts of protein, and vitamins. Nectar provides the energy that the Holly blue needs to fly.
The Holly blue uses various nectar plants, such as Eupatorium (Eupatorium), Spanish lavender (Lavandula stoechas), Alder buckthorn (Rhamnus frangula), and Common heather (Calluna vulgaris).
To help the Holly blue butterfly, plant (some of) these plant species in your garden. Combine host plants and nectar plants so that you support both the caterpillar and the butterfly!
Caution with some plant species
The berries of the Alder buckthorn (Rhamnus frangula) are poisonous to humans.
The berries of the Holly (Ilex) are poisonous to humans.
Common ivy (Hedera helix) contains berries that are poisonous to humans. Ingestion of the berries causes skin rash, fever, vomiting, abdominal pain, and drowsiness.
The fruits of the Common dogwood (Cornus sanguinea) are moderately poisonous.
Parts of the Liquorice milkvetch (Astragalus glycyphyllos) are poisonous.
The berries of European buckthorn (Rhamnus cathartica) are poisonous to humans.
Eupatorium (Eupatorium) is used in natural medicine. This plant has medicinal properties for the liver, urinary tract, kidneys, bones, joints, and digestive system. If large quantities of the whole plant are ingested, it is poisonous.
