Adonis Blue: a common sight in the Palearctic region

Adonis blue, also called Lysandra bellargus or Polyommatus bellargus is primarily present in the Palearctic realm, known for its strikingly blue upperside on males and brownish-blue on females.

Adonis Blue Butterfly Species Summary

Scientific nameLysandra bellargus, Polyommatus bellargus
Family nameLycaenidae
HabitatChalk downland, warm, sheltered spots, areas with vegetation
Range The palearctic realm
Host PlantsHorseshoe vetch (Hippocrepis comosa)
Butterfly DescriptionMales strikingly blue, females darker
Caterpillar DescriptionGreen, with yellow lines from front to back

What Color is Adonis blue?

Adonis Blue Male
Adonis Blue Male

Adonis blue (Lysandra bellargus, Polyommatus bellargus) belongs to the family Lycaenidae. Male Adonis blue is brilliant sky blue on the upper side, with a thin black line near the white edge of the wings. The wingspan is around 1.2 in (3 cm).

Female Adonis is chocolate brown with some blue scales near the base of the wings. They also have orange spots around the edges of their hind wings. Both sexes have similar underwings — brownish grey with orangey spots.

Their most distinctive feature is the black line going through the white fringe. They’re similar to Chalkhill blue, but their lines are brownish.

Adonis Blue Caterpillar Description

While adult butterflies are blue, the caterpillars are green. They reach 0.63 inches (1.6 cm) in length. Their dark green body also has yellow stripes along the back and sides.

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This larva feeds during the day and goes through 5 instars. The first instar is pale yellow and fine. Still, it feeds only for a few days, then overwinters. The second instar is pale olive, still feeds on leaves and rests under them. The third instar remains olive-green, and the fourth instar is even richer in color. The final instar has recognizable yellow lines.

This larva also has a Newcomer’s gland, which provides secretions that attract ants, which protect it from predators.

The pupa (chrysalis) stage is light green and turns brown as it ages.

Adonis Blue Butterfly Lifespan

  • Egg stage – controlled by temperature, from about 2 weeks in the summer to over 6 weeks in late autumn
  • Caterpillar – if not overwintering, about 1 month
  • Chrysalis stage – about 3 weeks
  • Adult butterfly stage – unknown

Ideal Habitat

Adonis blue frequents chalk downland, warm, sheltered spots, areas with vegetation, flowery hillsides, limestone grassland, and south-facing slopes. Its ideal habitat is dry and hot, packed with horseshoe vetch (Hippocrepis comosa), which likes thin calcareous soils. Sometimes, it will visit human-made platforms, like the one on Martin Down in Dorset.

Usual Host Plants

Horseshoe vetch (Hippocrepis comosa) is the only host plant for this butterfly species. Caterpillars will rest at their base to stay protected from the sun.

Adonis Blue Diet

Horseshoe vetch acts also acts as the food plant for caterpillars. Early caterpillar instars feed by grazing one side of the leaf and rest at the base of the food plant, sometimes on bare soil. Adult butterflies drink flower nectar.

Life Cycle and Behavior

Adonis Blue Female
Adonis Blue Female

This butterfly has two broods, one in the second half of May, lasting until June, and the other in the second half of August, lasting until the beginning of September.

Adonis butterflies live in concentrated colonies. They seem as if they have limited potential for dispersal. Still, when observed in a good environment, hundreds of them could be in one area. They also roost communally during the night. Their flight is fast and erratic, and they’re observed flying low above the vegetation.

Females lay eggs one by one, usually on the underside of the food plant leaves. Eggs laid in May/June will hatch in about a week, while those laid in the fall will take several weeks longer.

Symbiosis with ants

Adonis is one of the rare butterflies that forms a symbiosis with ants. This relationship starts during the caterpillar stage, where the larva attracts ants with the secretion of honeydew. This is why Adonis butterflies may be common around ant nests. Ants are also known to protect the chrysalis.

Common Predators

Adonis blue butterflies are common in the UK, where shooting game birds is popular. Unfortunately, many non-native birds were released in the past decade to support the hobby. The increased number of birds had an adverse effect on wildlife, including this butterfly species. Other predators may include insects and small mammals.

Are Adonis Blue Butterflies Poisonous?

While Adonis butterflies aren’t toxic, they form a symbiotic relationship with ants. Ants enjoy the secretion of honeydew from the caterpillar, and caterpillars and chrysalises enjoy ants’ protection.

Is it possible to see an Adonis blue butterfly in Canada?

There are barely any reports of Adonis blue in North America, except for one in Washington. The most common sightings include the Palearctic realm:

  • Caucasus
  • Central Europe
  • Iran
  • Iraq
  • Southern Europe
  • Southern Russia
  • Turkey
  • Western Europe

Do Adonis Blue Butterflies Migrate?

This butterfly species doesn’t travel far. Colonies may get isolated and vulnerable if their habitat is disturbed.

Are Adonis Blue Butterflies Endangered?

At the moment, the butterfly conservation priority for Adonis is medium. This species heavily depends on calcareous grassland and has suffered from habitat loss and poor habitat management. This is why many experts are concerned about it.

Furthermore, this species has always been restricted to warmer, dry calcareous grasslands of southern England. In the last 50 years, there has been an evident decline in numbers due to new agricultural practices. The total population in Britain has seen a 90% decline during this time. Therefore, Adonis is no longer present in Cambridgeshire, Essex, and Suffolk.

However, the most recent climate change, which brought hot and dry weather, may improve the butterfly’s status. For example, this species was noticed in 2006 in the Cotswolds in Gloucestershire after being gone for 40 years.

There are also active attempts to help species conservation. Habitat management for Adonis blue includes allowing plants to flower or strategically placing or removing shrubs to create the ideal environment.

Why Are They Called Adonis Blue Butterflies?

Male Adonis is brilliantly blue, which is why it was assigned the name. Plus, Adonis is known as a beautiful young man and lover of the goddess Aphrodite in Greek mythology, so the name was perfect for this butterfly.

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