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Dolomedes

life science Maturity 7-9 Next article →

Dolomedes are a group of large spiders.

Water spider 2
Water spider 2

Many people call them fishing spiders or raft spiders. Most species in this group live near water. Some live in bogs or forest streams. A few even live in trees. The name Dolomedes comes from a Greek word. It means wily or deceitful. These spiders are very interesting because they use water in special ways. They can live on top of it or even underneath it.

These spiders do not hunt using a web. Instead, they use the water surface like a web.

Fishing Spider and dime
Fishing Spider and dime

They sit at the edge of a pool or stream. They stretch out their front legs to feel for movement. They have tiny, sensitive hairs called trichobothria on their legs. These hairs help them feel vibrations in the water. The spider can tell if a vibration is a struggling insect or just a falling leaf. When they find prey, they run fast across the surface. They use their front legs to grab the meal and then use venom to kill it.

Cameroon Clawed frog tadpole being consumed by fishing spider
Cameroon Clawed frog tadpole being consumed by fishing spider

Living near water requires special tools. Dolomedes are covered in short, velvety hairs. These hairs are hydrophobic, which means they do not like water. This helps the spider stay on top of the surface tension.

Dolomedes sling
Dolomedes sling

They can also dive under the water. When they do, air gets trapped in their body hairs. This creates a thin, silvery film of air around them. This air film lets them use their book lungs to breathe while submerged. This trapped air also makes them very buoyant. If they let go of a plant, they will float to the top.

There are over one hundred different species of Dolomedes. Some live in New Zealand, like Dolomedes aquaticus. Others live in Europe, such as the raft spider, Dolomedes fimbriatus.

Rangatira-spider-Dolomedes-schauinslandi
Rangatira-spider-Dolomedes-schauinslandi

Some species are very large. A female can have a leg span of up to 10 centimeters. These spiders are nocturnal hunters. This means they hunt at night when birds are sleeping. This helps them stay safe from predators like birds and snakes. Even some wasps, called Spider Wasps, try to hunt these spiders.

It is easy to mistake these spiders for wolf spiders. However, you can tell them apart by looking at their eyes. Dolomedes have eight eyes in two rows. Wolf spiders have eyes in three rows.

Nursery web spider 1
Nursery web spider 1

You can also look at their legs. Fishing spiders have thickset legs that help them fight large prey. Some even eat small fish like sticklebacks or goldfish. This shows how strong and capable these spiders really are. They are masters of life on the water's edge.

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🖼️ Images & Media (8)
File:Water spider 2.jpg
Water spider 2.jpg
File:Fishing Spider and dime.jpg
Fishing Spider and dime.jpg
File:Cameroon Clawed frog tadpole being consumed by fishing spider.jpg
Cameroon Clawed frog tadpole being...
File:Male Nursery Web Spider.jpg
Male Nursery Web Spider.jpg
File:Nursery web spider 1.jpg
Nursery web spider 1.jpg
File:Dolomedes sling.jpg
Dolomedes sling.jpg
File:DolomedesEggsack.jpg
DolomedesEggsack.jpg
File:Rangatira-spider-Dolomedes-schauinslandi.jpg
Rangatira-spider-Dolomedes-schauinslandi.jpg
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