Euura proxima facts for kids

Euura proxima is a small insect known as a sawfly. It's part of the Tenthredinidae family, which are common sawflies. The young sawflies, called larvae, feed inside the leaves of willow trees. This sawfly was first described by Jean Guillaume Audinet-Serville in 1823.

What is a Sawfly Gall?

A gall is a special growth on a plant. It's like a small house made by the plant itself. The Euura proxima sawfly creates a gall on willow leaves. This gall is shaped like an oval or a bean. It can be up to 12 millimeters long and 6 millimeters wide.

When the female sawfly lays her egg, she also injects a substance into the leaf. This substance makes the plant grow a hard, thick wall around the egg. At first, the galls are green. As the larva inside eats the plant tissue, the walls become softer. Sometimes, a gall might be empty. This can happen if an egg wasn't laid or if it didn't hatch. You can often find several galls on one leaf. They usually don't touch the main vein of the leaf.

Willow Trees and the Sawfly Gall

E. proxima galls are found on several types of willow trees. These include white willow (S. alba) and weeping willow (S. babylonica). They also appear on S. x blanda, S. excelsa, crack willow (S. fragilis), and bay willow (S. pentandra).

Life Cycle of the Sawfly

The Euura proxima sawfly usually has two generations each year. The first group of sawflies grows up around mid-summer. The second group matures in the autumn.

E. proxima is one of three very similar sawfly species. The other two are:

• E. bridgmanii
• E. triandrae

Other Creatures in the Gall

Sometimes, other insects move into the sawfly's gall. These are called inquilines. An inquiline is like a guest that lives in someone else's home. They often harm the original host. Here are some insects that can be found in E. proxima galls:

• Archarius salicivorus: This is a type of weevil. A female weevil lays her egg inside the Euura gall. The weevil larva then grows and usually kills the sawfly larva. However, the weevil larva doesn't eat the sawfly larva. You can tell a weevil larva apart because it doesn't have feet and curls up like a horseshoe. It changes into an adult in the ground. The weevils born in autumn spend the winter as adults.

• A. crux: This is another weevil. It also has two generations a year. The female weevil lays her egg in Euura galls. The larva of this weevil will eat the original sawfly egg or larva. It also changes into an adult in the ground. Weevils born in autumn hibernate through the winter.

• Euphranta toxoneura: These are fruit flies from the Tephritidae family. The larva of E. toxoneura feeds inside this gall. It also feeds in the galls of Euura bridgmanii. This fruit fly larva first kills the host sawfly larva. Then, it pushes the dead sawfly larva out of the gall. When the fruit fly larva is fully grown, it leaves the gall and changes into an adult in the soil.

Where Euura proxima Lives

This sawfly species is found all over Europe. It lives as far north as southern Finland and as far east as the Caucasus mountains. It has also been brought to other parts of the world, including Australia, North America, and New Zealand.