What do they look like?

This group of butterflies get their common names from their wings. Some groups have shiny blue on their wings, others are the color of copper. Some have very thin little "tails" on their wings that are called hairstreaks. Many are not so colorful, and have gray or brown wings with spots of black, white, or orange. They are usually small butterflies, with wingspans of 25 mm or less. Some species have males with reduced front legs like the Brushfoot family, but females always have all 6 legs for walking and standing.

Caterpillars in this family have small heads and legs, and sometimes look like slugs covered with tiny hairs. Most are green or brown, but a few are yellowish or reddish. Some can pull in their heads completely, like a slug.

Where in the world do they live?

There are nearly 5,000 species in this family around the world, but most only live in the tropics. We only have about 145 in the United States, and 32 species in Michigan.

What kind of habitat do they need?

Adults in this family are usually found close to the food plants of the caterpillars. This usually means around forest edges, open fields, along streams, and other open but vegetated areas.

Caterpillars in this family are found on their food plants, or in the company of ants.

How do they grow?

Like all Moths and Butterflies, this family has complete metamorphosis. See More Information on Butterflies and Moths for an explanation of this. Some species in this group spin cocoons, others don't but the pupae attach themselves to plant stems with silk. Different species overwinter in different stages, usually larvae or pupae, rarely eggs and never as adults.

How do they reproduce?

After mating, females lay eggs one by one on the flowers, twigs or leaves of food plants. This group often has two generations a year, one that spends the winter as caterpillars or pupae and fly as adults in the spring, and a second that complete their life-cycle in the summer and fly as adults in the fall.

These butterflies don't care for their young.

How long do they live?

All Blues, Coppers, and Hairstreaks live for a year or less. Many complete their whole life in a few months.

How do they behave?

Adults in this family fly only in daylight. They often only fly short distance, and may stay within a few tens of meters their whole lives. A few species do migrate and they fly much further. Some caterpillars feed only at night.

How do they communicate with each other?

These butterflies communicate mainly with their scent and their colors. Males attract mates with scent and display, and females leave a scent mark on plants where they have laid eggs.

What do they eat?

Caterpillars in this family eat a wider variety of foods than other butterfly families. Some species eat leaves, but others specialize in flowers or fruit. One species is a predator! This is very rare in butterflies and moths. It feeds on wooly aphids, and females lay their eggs near their insect prey.

Some adults sip nectar, but many prefer tree sap or puddles.

What eats them and how do they avoid being eaten?

These species are not usually toxic to predators. The caterpillars sometimes make silk nests to hide in, or rely on ants for protection. Some adults rub their hindwings together whenever they land. This may draw predators attention to the eyespots or hairstreaks on their wings, confusing a predator about where their head is.

What roles do they have in the ecosystem?

Adults help pollinate flowers. Caterpillars usually aren't a major factor for plant populations, but sometimes are when they occur in large populations. Many species in this group have caterpillars that have mutualistic relationships with ants. The caterpillars have glands that produce liquids that the ants like to drink, and in exchange the ants protect the caterpillars from predators, and in a few species even take the caterpillars into their nests.

Do they cause problems?

These butterflies don't have strong effects on people one way or another. A few species sometimes eat crop plants but this is not common and they rarely do enough damage to matter.

Are they endangered?

One species in Michigan is considered endangered. It is Lycaeides melissa samuelis, the Karner Blue. Scientists are still not sure if it is just a subspecies of a more common species, or if it is a completely separate species. The Karner Blue only exists in a few small populations scattered from Minnesota to New York. It needs dry pine-oak barrens to live in, and only feeds on one kind of plants (lupines, genus Lupinus). This habitat has mostly been converted into agricultural fields, and is hard to find.