Common Blue: a two-minute wildlife lesson

Butterflies of Europe · day 6 of 7

Five facts

1. Males are bright blue, females mostly brown with orange spots. But a female that grows up in colder weather ends up bluer.
2. Its blue isn't a pigment. It comes from tiny bubble-like structures in the wing scales that play with light.
3. Ants look after its chrysalis and often carry it into their nest. In return, they feed on a sweet honeydew the caterpillar makes.
4. It stores pigments from its food plants in its wings. Females store about 60% more than males, which may make them easier to spot.
5. In 2023, the common blue was voted Israel's national butterfly. Like the country's flag, it is blue and white.

The quiz

1. What can make a female common blue bluer?

• Eating blue flowers
• Developing in colder temperatures (correct)
• Growing older
• Living by the sea

Colder temperatures during development produce bluer adults, especially females.

2. Where does the common blue's blue colour come from?

• A blue pigment from its food
• Dust from flowers
• Tiny bubble-like structures in its scales (correct)
• Drops of water on its wings

Its blue is a structural colour made by bubble-like nanostructures.

3. What do ants get from the common blue caterpillar?

• Sweet honeydew (correct)
• Silk for their nest
• Fresh leaves
• Protection from birds

The caterpillar makes honeydew, which the ants eat.

4. Who stores more plant pigments in their wings?

• Males
• Both store the same amount
• Neither: they make their own
• Females (correct)

Females store about 60% more of these pigments than males.

5. Which country chose the common blue as its national butterfly in 2023?

• Greece
• Ireland
• Israel (correct)
• Canada

It was elected Israel's national butterfly in 2023.

More about the Common Blue

Same week

All lessons

Nature documentaries