Common Blue Butterfly: Identification, Life Cycle, and Behavior

In this article, you’ll uncover everything about the Common Blue butterfly. You’ll grasp its identification, life cycle, and unique behaviors.

Get ready for an in-depth look at this captivating creature.

Common Blue butterfly

What is the Classification of Common Blue?

The Common Blue, scientifically classified as Polyommatus icarus, belongs to the large family of Lepidoptera, which includes butterflies and moths.

This species resides within the Lycaenidae family, often referred to as the gossamer-winged butterflies.

Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Lycaenidae Genus: Polyommatus Species: Icarus

This butterfly is one of approximately 5,000 species living under the Lycaenidae canopy, emphasizing the immense biodiversity within this family alone.

The genus Polyommatus is specifically known for species characterized by vibrant blue coloration, which the Common Blue brilliantly exemplifies.

Bearing the mythical name of Icarus—who flew too close to the sun in Greek mythology—it is befitting of this creature’s adventurous nature and skyward habitat.

Through understanding the classification of the Common Blue, you gain more than just a name. You uncover a narrative intricately woven into the taxonomy of this exquisite creature.

What is the Distribution of the Common Blue?

The Common Blue butterfly (Polyommatus icarus) is a well-travelled butterfly species. With a range that spans from North Africa to Europe and even parts of Asia, it has adapted to be able to survive in a variety of different climates and terrains.

  • In the UK, Common Blues can be found almost anywhere. Grasslands, heathlands, and even your garden are just a few of the places you might catch a glimpse.
  • In Asia, they reside mostly in temperate regions. They show a preference for meadows and sunny clearings.
  • North Africa offers another suitable habitat. Scrublands, forests, and meadows are where they’re generally found.

Despite the species being ‘common’, recent decades have seen a decline in their numbers in certain areas. Particularly in the UK, over the past 40 years, their population has decreased by nearly 50% due to habitat loss and change in land use.

This distribution paints a stark picture of the impact human activities can have on even the most adaptive of species like the Common Blue.

Take note of the habitats you visit. Remember to watch out for this beautiful specimen. It dances in the air with such a unique cadence, you won’t want to miss it!

What are the Main Characteristics of the Common Blue?

The Common Blue is distinctively captivating, exhibiting alluring shades of blue. Males parade a vibrant blue color, brilliantly noticeable when their wings are spread.

Females, on the other hand, have a distinctive brown color with scattered blue scales and orange crescents decorating the borders of their wings.

In terms of size, the Common Blue is relatively small with a wingspan typically ranging from just 1.3 inch to 1.5 inches (33mm-38mm).

Also, these butterflies possess quite a visible trait of having offset pairs of white-ringed black spots on the underside of their hind wings.

These butterflies primarily inhabit grassy fields, meadows, parks, and gardens. Unlike many other butterfly species, the Common Blue has a habit of closing its wings soon after landing.

This behavior aids in their camouflage as the underside of their wings tends to blend well with the surroundings.

While the color variance and patterns serve as the main differentiation factors, Common Blue also has a peculiar flight pattern.

They are known for their erratic, fast, and low flight, fluttering above ground level, before settling on a plant.

How to Identify Male and Female Common Blue?

Identifying the gender of the Common Blue butterfly is a simple task, once you know what to look for. The key differences lie in their color and pattern.

Males are a vibrant blue, thus lending them the name, ‘Common Blue.’ They also bear a set of thin black borders around the wings of the butterflies.

But be wary not to confuse them with the Adonis Blue or the Holly Blue, which are also of the blue hue.

On the other hand, females primarily display a brown coloration with orange spots along the boundaries of the wings.

Their upper wings may have a dusting of blue near the body but it’s not as pronounced as in males.

Let’s illustrate the distinguishing features:

Gender Color Borders Potential for Confusion
Male Vibrant Blue Thin Black Adonis Blue, Holly Blue
Female Brown with Orange Spots Occasionally blue near body None

Remember, male or female, the Common Blue has a wingspan between 1 and 1.4 inches (27-36mm). While exploring, take your time to observe these beautiful creatures, as identifying them rightly may enhance your appreciation for them.

What is the Mating Ritual of Common Blue?

The mating ritual of the Common Blue butterfly is a spectacle to behold. First and foremost, males stake out territories—usually rich in flowers—to attract the females.

Like warriors waiting for a challenge, male Common Blues perch on a prime spot early in the morning, ready to defend their area from rivals.

Watch as the vibrant, blue-marked males make their presence known. They’ll fly abundantly, darting through the air chasing off competitors and making aerial maneuvers that would put an acrobat to shame.

It’s the butterfly equivalent of flexing and showing off, with the males demonstrating physical prowess and eagerness to protect their chosen territory.

Behavior takes a dramatic turn when a female flies into the picture. Placed within the protective territory, she becomes the object of the male’s adoring attention, and the mating dance begins.

The male envelops her in a cloud of pheromones, erotic scents that leave no room for misinterpretation.

With a flick of his wing, his chemicals surround the female, triggering in her an instinctual urge to reproduce.

This courtship dance is not a quick affair. It may last several hours, during which the male and female flutter around each other, sometimes even touching wings.

It’s a delicate, measured dance that requires the participation of both parties. The female signals her acceptance by allowing the male to rest his antennae on her wings, a gesture that signals her consent.

You’ve now witnessed the first step on the journey of life for new Common Blues. It’s a magical process that reveals not just the beauty, but the intricate behaviors of these captivating creatures.

What Does the Caterpillar of Common Blue Look Like?

The caterpillar of the Common Blue butterfly is a fascinating creature to observe. Just like its adult counterpart, it has a unique outward appearance that’s necessary for its survival.

Often, you’ll see Common Blue caterpillars in a range of colors from pale green to brownish grey.

Their shades are an adaptation that allows them to blend with the leaves and stems of their host plants. However, common identifying features remain constant.

Studying their physical attributes, these caterpillars are typically 14-16 millimeters long, which is equivalent to about 0.5-0.6 inches. They’re covered with minute hairs which give a feel of rough texture when touched lightly.

Your focus should be on their body pattern. Common Blue caterpillars showcase a white line that runs along the center of their back, flanked by alternating lighter and darker stripes on each side.

This patterning acts as an impressive camouflage system, deceiving potential predators.

To finish off their unique look, each caterpillar sports a reddish-brown head, which is small and scarcely seen due to being retracted most of the time into the body.

It indeed takes a keen observer to spot these cleverly disguised creatures in the wild.

Next time you’re out in nature, why not accept the challenge and try to spot one of these marvelously camouflaged caterpillars?

Remember, observing without disturbing is the key to respecting and preserving their much-needed habitat.

What is the Life Cycle of Common Blue?

The life cycle of the Common Blue butterfly is fascinating and quite specialized. Like many other species of butterflies, it undergoes a process known as complete metamorphosis, with four main stages: egg, larva (caterpillar), pupa (chrysalis), and adult.

First, the female butterfly lays her eggs on the underside of host plants. Bird’s-foot trefoil and clover are some common plants preferred. The eggs are left there for about a week until they hatch into the larval or caterpillar stage.

The caterpillar then spends their time eating and growing. As it completes each growth stage, the caterpillar sheds its outdated skin in an event known as molting. After several molts, the caterpillar is ready to enter the pupal stage.

The caterpillar forms a chrysalis or pupa. Within this structure, it undergoes a transformation, breaking down its body and rebuilding it into the structure of the adult butterfly. This part of the life cycle typically lasts for about 2 weeks.

Lastly, the transformed adult butterfly emerges from the pupa, fully formed but needing a few hours for its wings to dry and harden before it can fly.

This cycle varies in length depending on the environmental conditions. In the wild, it could take around 4 to 6 weeks.

In general terms, the adult Common Blue butterfly may live only for a few weeks to about a month. They live long enough to mate and lay eggs to ensure the survival of the species.

What Is the Average Life Expectancy of a Common Blue?

As you delve deeper into the enticing world of butterflies, understanding their longevity is key. On average, the Common Blue butterfly (Polyommatus icarus) lives for about a month.

However, each stage of their life cycle has a different duration:

  1. Egg: The Common Blue butterfly starts its life as an egg which lasts for about a week.
  2. Caterpillar: The next stage includes a two-week journey in the caterpillar form.
  3. Chrysalis: The pupal stage, or the chrysalis, also takes around two weeks.
  4. Butterfly: Lastly, the butterfly stage itself lasts for nearly a month, given favorable conditions.

Take note, these durations are averages. Stresses such as weather and predation can significantly impact the lifespan of a Common Blue.

Their life may seem short, yet it is filled with significant transformation and beauty. Ultimately, like many things in the natural world, the lifespan of a Common Blue butterfly is determined by a combination of genetics, environmental factors, and a touch of luck.

Remember, the lifecycle of a butterfly, including the Common Blue, demonstrates the delicate, almost poetic balance of nature.

Every stage, every day is important in the continuation of their species. Appreciating these fragile creatures’ life span helps us become aware of the urgency of maintaining their habitats, and the broader ecosystem, in a healthy state.

What Does the Diet of a Common Blue Consist Of?

When it comes to the diet of the Common Blue butterfly (Polyommatus icarus), it’s all about nectar. This type of butterfly is especially fond of flowering plants, where they can find ample nectar supplies for their subsistence. As larvae, they feed on leguminous plants species.

The Common Blue embraces a diverse array of flowering plants. From the vibrant Red Clover (Trifolium pratense) to the humble daisy.

These butterflies prefer wildflowers, displaying a preference for native species. They extend their natural sugar source by frequenting garden flowers as well.

One moment you may find them sipping the nectar of Marjoram, the next at a Daisy or Thyme. Their preference lands on plants blooming in their habitat at the time.

So, if you’re on a butterfly-spotting adventure, let your eyes guide you towards the nearest wildflower meadow.

The caterpillars of Common Blue have a rather selective palate in contrast. Their diet consists mainly of legumes, specifically focusing on bird’s foot trefoil (Lotus corniculatus), a wild legume found in many of their habitats.

Common Blue larvae are myrmecophiles. They share a symbiotic relationship with ants. The caterpillars produce a sweet substance relished by ants, and in return, the ants offer protection to the larvae.

This fascinating relationship ensures survival during the vulnerable larval stage.

As you can see, the Common Blue’s diet is a delicate balance of nectar and legumes. Whether as a fluttering adult or a small caterpillar, the diet of the Common Blue connects them directly to the landscape surrounding them.

It’s a relationship of give and take, each element relying on the other for survival. Truly, this diet is as beautifully complex as the Common Blue itself!

Which Plants Serve as the Primary Hosts for Common Blue?

Common Blues are discerning when it comes to their transition from caterpillar to butterfly. They require certain host plants for survival. Without these plants, Common Blues can’t thrive.

Bird’s-foot Trefoil (Lotus corniculatus) is the primary host for Common Blue. Its leaves and shoots provide crucial food for Common Blue caterpillars. They feast on this plant until they’re ready to pupate.

White Clover (Trifolium repens) and Black Medick (Medicago lupulina) are also vital for their survival. These plants offer valuable nourishment for Common Blue caterpillars.

They’re found in good quantities where populations of Common Blue are high.

The choice of these plants is not random. They are rich in phytochemicals. These natural chemicals help caterpillars grow and defend against predators.

In addition to being essential food sources, these plants are also egg-laying sites for female Common Blue butterflies.

Here’s a table with the main host plants of Common Blue:

Common Blue’s Host Plants
Bird’s-foot Trefoil
White Clover
Black Medick

Remember, more diversity equals more butterflies. Plant these species in your garden to attract and host Common Blue butterflies.

You’ll support their population and contribute to maintaining biodiversity.

To conclude, Common Blues depend entirely on these plants for their life cycle. It underlines the importance of these plants in preserving the butterflies’ number.

What are the Unique Mimicry Behaviors in Common Blue?

When observing the delicate Common Blue, you might notice a fascinating phenomenon: mimicry. Mimicry in the animal kingdom often functions as a survival technique, and for this particular butterfly, it’s no different.

Common Blue butterflies show Batesian mimicry. This means they have evolved to look like other, less palatable species, to ward off predators.

To comprehend this, picture the bitter-tasting, yet pretty, Adonis Blue. The Common Blue masks itself as this less appetizing relative to mislead predators and escape harm.

Strikingly, only the female Common Blues display this behavior. They exhibit variability in their wing patterns, appearing similar to the male Adonis Blue, deterring potential threats.

The males, on the other hand, with their vibrant blue wings, do not exhibit this mimicry.

In addition to Batesian mimicry, Common Blues exhibit other behaviors for survival. One impressive tactic is their ability to hibernate.

Yes, you heard it right. These butterflies can hibernate as larvae in colder months, ensuring their survival despite harsh weather conditions.

Mimicry, apart from being a wonderful display of nature’s wizardry, demonstrates the adaptability and resilience of the Common Blue.

So next time you spot one of these creatures, take a moment to appreciate the remarkable survival techniques they’ve developed over the centuries.

What Are the Main Threats to Common Blue Populations?

Unfortunately, the Common Blue butterfly faces several significant threats.

First and most pressing is habitat loss due to human activities. Whether through agriculture, urban development, or other environmental adjustments, their natural homes are gradually being eroded.

  • Agriculture: Large-scale farming methods can destroy the habitats that these butterflies need for survival. It’s not just the physical changes to the land, but the use of pesticides that pose a danger.
  • Urban development: As our cities expand, the untouched meadows and grasslands the Common Blue needs are being eaten away. Parks and reserves often can’t replicate the same biodiversity.

In addition, climate change is impacting Common Blues. As global temperatures rise, it can disrupt their reproductive cycles and hibernation patterns, ultimately leading to lower population numbers.

Thirdly, invasive species are also a reason for concern. It’s not uncommon for invasive ants or other predators to disrupt or destroy Common Blue nests and larvae.

So, the Common Blue butterfly is under great pressure. Yet, with collective action – be that in more sustainable agriculture, curbing climate change, protection strategies – we can counter these threats.

Remember, every species plays a crucial role in the Earth’s ecosystem. The smaller they are, the easier they can be overlooked, but the bigger the impact their loss could have.


In conclusion, the Common Blue isn’t just a pretty face – it’s a symbol of the fragile intricacies of nature that we often overlook.

From its specific feeding habits to its unique mimicry and mating rituals, every aspect of its existence is a testament to nature’s marvels.

What are your thoughts or experiences with the Common Blue? Please leave a comment below.

Butterflies   Updated: July 8, 2023
avatar Welcome to Insectic, a blog to learn about insects and bugs. I'm Richard, and I've created this website to share my experience, knowledge, and passion with others.

Leave a Comment

Your email address will not be published. Required fields are marked *