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Sticker of Alderfly
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Alderfly

Sialis lutaria
Eats: Nothing as a grown-upOther insectsPonds, rivers and shores6 legs

The alderfly is a stocky, dark brown insect with smoky see-through wings. When it rests, it folds its wings over its back like a little roof. It is a clumsy flier and never goes far from the pond where it grew up.

Lives in
Europe, near ponds and slow streams
Length
2 cm (0.79 in)
Wingspan
2.2 to 3.4 cm (0.87 to 1.3 in)
Top speed
about 3.9 km/h (2.4 mph)
Flying, estimate
Can it hurt you?
Harmless
Harmless. It does not bite or sting people.
What does it eat?
The grown-ups do not eat at all. Their babies live under water and hunt small water animals with strong jaws.
For real!Photo of Alderfly
Picture by Hectonichus. CC BY-SA 3.0, via Wikimedia Commons.

How big is it?

How long is it?

Alderfly about 2 cm long (0.79 in)A grain of rice about 6 mm (0.24 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)

How wide are its wings?

Alderfly wings about 3.4 cm tip to tip (1.3 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)A banana about 18 cm (7.1 in)
as long as 3 grains of rice in a rowwings as wide as 6 grains of rice in a rowcould fly across a whole football pitch in 97 secondsmoves 54 times its own body length every second

How big is Alderfly compared to YOU?

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How fast is it?

cool stuff

Fun facts

1

The grown-up alderfly lives for only two or three days and does not eat anything.

2

Its babies live in the mud under water for one or two years.

3

The baby has big jaws and feathery gills on its sides for breathing under water.

4

The mother lays lots of eggs on plants hanging over the water. When the babies hatch, they drop straight in.

5

You can see grown-ups mostly in May and June.

you asked

Most asked questions about Alderfly

?What does an alderfly eat?

Grown-ups do not eat. The larvae hunt small animals under water.

?How long does an alderfly live?

Its whole life takes one or two years, but the grown-up lives only two or three days.

?Is the alderfly dangerous?

No. It is harmless to people.

For bug experts

Scientific name
Sialis lutaria
Named by
Linnaeus, 1758
Group
Other insects
Family
Sialidae
Classification
Insecta > Megaloptera > Sialidae
Lives on
Europe

Where the facts come from

  1. Sialis lutaria (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Hectonichus. CC BY-SA 3.0, Wikimedia Commons. The round sticker of this bug is cut from the same picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

More from the same group: Other insects

Also at home here: Ponds, rivers and shores