Karner blue facts for kids
Quick facts for kids Karner blue butterfly |
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| Conservation status | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Lepidoptera |
| Family: | Lycaenidae |
| Genus: | Plebejus |
| Species: |
P. melissa
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| Subspecies: |
P. m. samuelis
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| Trinomial name | |
| Plebejus melissa samuelis Nabokov, 1944
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| Synonyms | |
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Lycaeides melissa samuelis (Nabokov, 1944) |
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The Karner blue (Plebejus melissa samuelis) is a small, beautiful blue butterfly. It is an endangered species in the United States. You can find it in some Great Lakes states, parts of New Jersey, and southern New Hampshire. It's even the official state butterfly of New Hampshire!
This butterfly's entire life depends on a special plant: the wild blue lupine flower (Lupinus perennis). Without this flower, the Karner blue butterfly cannot survive. Because of this, it was declared an endangered species in 1992.
The famous writer Vladimir Nabokov was the first to study and describe this butterfly. He named it after Karner, New York, where he first found it. This area is part of the Albany Pine Bush.
Contents
Life Cycle and Reproduction
Karner blue butterflies have two generations each year. The first group of butterflies flies from late May to mid-June. The second group flies from mid-July to mid-August. This timing matches when the wild lupine flowers bloom.
The eggs laid in late summer stay safe through the winter. They hatch in mid-to-late April. It takes about 25 to 60 days for a Karner blue to grow from an egg to an adult butterfly. Adult butterflies usually live for only 3 to 5 days.
First-generation females lay most of their eggs on wild lupine plants. These eggs grow into the second generation of adult butterflies. Second-generation females also lay eggs near lupine, but they might also lay them on grasses or other plants. The second generation is usually much larger than the first.
What Karner Blues Look Like
These small butterflies have a wingspan of about one inch. The males and females look different.
- Males: The top of their wings is silvery or dark blue. They have thin black edges.
- Females: The top of their wings is grayish-brown, especially near the edges. Some parts might be blue. They have orange crescent shapes in a wavy pattern near the black border.
The underside of both male and female wings is gray. They have a line of orange crescents along the edges. There are also scattered black spots with white circles around them.
Where Karner Blues Live
Karner blue butterflies live in parts of Minnesota, Wisconsin, Michigan, and New York. People are trying to bring them back to Ohio and New Hampshire. Sadly, they have disappeared from Iowa, Illinois, Pennsylvania, Massachusetts, Maine, and Ontario, Canada.
These butterflies love open areas like oak savannas and pine barrens. They also live in places that are often disturbed, like old fields, roadsides, and areas along power lines. These disturbed spots often have the right plants for them.
Wild Lupine: Their Special Plant
Wild lupine is the only plant Karner blue butterfly caterpillars eat. This means the butterflies need healthy lupine plants to survive. Studies show that more lupine usually means more Karner blue butterflies.
However, older lupine plants that are dying are not good food for the caterpillars. Young lupine plants might also not be the best. The best lupine plants for caterpillars have larger leaves and thicker stems. Lupine plants with more nitrogen in their leaves help caterpillars grow faster.
Sunny and Shady Spots
Karner blue butterflies need a mix of sunny and shady areas. This is because different parts of their life cycle need different conditions.
Adult butterflies prefer open, sunny places. In these spots, they can find more lupine and nectar flowers. It's also warmer, allowing them to fly and find mates more easily.
Female butterflies sometimes use shadier spots more than males. This might be to avoid too many males or to find better quality lupine plants.
Caterpillars often do better in shaded areas. This is likely because shade helps the wild lupine stay healthy longer. Lupine grown in the shade can be more nutritious for the caterpillars. In sunny areas, lupine might dry out too quickly, leaving caterpillars without food.
Nectar Flowers for Adults
Adult Karner blue butterflies drink nectar from many different kinds of flowers. They need these flowers for energy. The types of flowers they use can change depending on the time of year.
Some common nectar sources include:
- Canadian horseweed
- Spotted beebalm
- Butterfly milkweed
- White sweetclover
- Flowering spurge
- Common cinquefoil
- New Jersey tea
- Goldenrods
Open, sunny areas usually have more nectar flowers. This is another reason why these areas are important for adult butterflies.
How Disturbances Help
Karner blue butterflies seem to do well in areas that are disturbed. This can include things like controlled fires, vehicle traffic, or clearing land. These disturbances help keep the habitat open and sandy, which is perfect for wild lupine.
For example, in Wisconsin, areas with more disturbances had more Karner blue butterflies. Military vehicle traffic even helped the lupine plants get more caterpillar feeding damage, which means more caterpillars were eating there.
Temperature Effects
Temperature directly affects Karner blue butterflies. They start flying when it's around 76-80°F (24-27°C). If it gets too hot, around 96-98°F (35-37°C), they start to show signs of stress.
Temperature also affects where they lay eggs. On cool days, females prefer to lay eggs in sunny spots. On hot days, they move to shadier areas to lay their eggs.
Cold winters can harm the first generation of butterflies. Snow cover can protect their eggs from freezing or getting too hot from direct sunlight.
Habitat Size and Connections
Karner blue butterflies need a mix of different habitats. This helps them meet their needs throughout their life. They need open areas for adults and nectar, and shadier spots for egg-laying and caterpillars.
Larger patches of habitat are better for Karner blue butterflies. Smaller patches are more likely to lose their butterfly populations. It's also important for these habitat patches to be close together. This allows butterflies to move between them. Experts suggest that patches should be within 230 feet (70 meters) of each other.
Sometimes, people create "corridors" or pathways of suitable habitat. These corridors help butterflies travel safely between different areas.
Who Eats Karner Blues?
Many creatures prey on Karner blue butterflies.
- Caterpillars: Spiders, lady beetles, paper wasps, spined soldier bugs, and some ants eat Karner blue caterpillars.
- Adults: Dragonflies, robber flies, ambush bugs, assassin bugs, and spiders (like crab spiders) hunt adult butterflies.
- Other animals: Even white-tailed deer can accidentally eat Karner blue eggs, caterpillars, or pupae when they graze on lupine.
Some wasps and flies are also parasites of Karner blue butterflies. This means they lay their eggs on or inside the butterfly, and their young then feed on the butterfly.
Friends with Ants
Karner blue butterfly caterpillars have a special relationship with several types of ants. This is called a mutualistic relationship, meaning both benefit. Ants "tend" the caterpillars, protecting them from predators. In return, the caterpillars produce a sweet liquid that the ants like to drink.
Studies show that caterpillars tended by ants are more likely to survive. They also grow faster and gain more weight. This partnership is very important for the Karner blue's survival.
Protecting the Karner Blue
The biggest threats to the Karner blue butterfly are habitat loss and changes to their habitat. People are working hard to protect them.
- Habitat Restoration: This involves planting more wild lupine and managing areas to keep them open and suitable for the butterflies.
- Careful Management: Techniques like mowing or controlled burning can help maintain the right habitat. However, these activities must be done at the right time and in the right way to avoid harming the butterflies. For example, mowing should be done in fall or winter, and clippings should be left on the ground.
- Avoiding Harmful Practices: Activities that hurt lupine or nectar plants, or use pesticides that harm butterflies or their ant friends, are avoided.
It's important to plant a variety of nectar flowers that bloom throughout the season. This ensures adult butterflies always have food. Using native plants is best, as non-native plants can sometimes harm the natural food sources.
Conservation efforts are focusing on creating a mix of habitats. This includes both sunny and partially shaded areas, and connecting different habitat patches so butterflies can move freely.
- U.S. Fish and Wildlife Service (Midwest Region) Karner blue butterfly page
Images for kids
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Trail signage regarding the Karner blue at Miller Woods in Indiana Dunes National Park.
