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Hackled orbweavers

Uloboridae

What do they look like?

Like all spiders, hackled orbweavers have two body-segments, a cephalothorax in front and an abdomen behind. Adults are usually 3-10 mm long. They have eight legs, all attached to the cephalothorax. On the front they have two small "mini-legs" called palps. These are used to grab prey, and in mating, and are much bigger in male spiders than in females. Females in this family are often twice as large as males.

Michigan species in this family have two rows of four eyes each, though some tropical groups only have one row.

Unlike most spiders, this family doesn't have venom glands, their bite is harmless to people.

This is one of a few spider families that make a special kind of woolly, fuzzy silk. They have special structures on their abdomen and hind legs to produce this silk and make it into webs. This is where they get their name, webs made this way are called "hackled." See the Behavior section below for more information on this special webbing.

Most Hackled Orbweavers have dull colors: cream, gray, or brown are the most common.

Sexual dimorphism:

female larger.

Where in the world do they live?

Spiders in this family are found all over the world. Most species live in warm tropical climates, but we have a few species here in Michigan.

What kind of habitat do they need?

These spiders live in places with some vegetation, so they have places to put their webs. They also prefer warm and humid habitats, but a few species live in dry or cool places too.

These animals are found in the following types of habitat:

temperate; tropical; terrestrial.

Terrestrial Biomes:

taiga; chaparral; forest; rainforest; scrub forest; mountains.

Wetlands:

marsh; swamp; bog.

How do they grow?

Spiders hatch from eggs, and the hatchlings look more or less like grown-up spiders, though sometimes their colors change as they age. To grow they have to shed their exoskeleton, which they do many times during their lives.

How do they reproduce?

We know very little about reproduction in this family.

Key reproductive features:

seasonal breeding; sexual; oviparous.

Females make egg sacks of silks, sometimes attaching them to twigs or branches, sometimes lining them up in their webs. Unlike other spider groups, the silk of the egg sacks is often gray or brown.

Parental investment:

female parental care.

How long do they live?

Most spiders in this family probably live only a year or two at most.

How do they behave?

These spiders often hide during the day. They don't move around too much, but stay near the spot where they build their webs. Some species are solitary, others seem to live in groups, and attach their webs together.

How do they communicate with each other?

Like most spiders, Hackled Orbweavers use web-vibrations, touching, and scents to communicate.

What do they eat?

These spiders eat small insects and other invertebrates. They spin flat webs that often look like an orb web or a piece of an orb web. Hackled orbweavers usually spin their webs horizontally, unlike the regular orbweaver family that makes their webs vertical.

The webs made by this family aren't sticky. Instead they are made with "hackled" silk, which is fuzzy and has lots of tiny fibers. These little fibers easily tangle up prey. Also, many species of hackled orbweavers stretch their webs and hold them tight. When a prey animal bumps into the web, it lets go of the web so that it collapses around the unlucky insect. Whenever they catch an animal in their web, they grab it and wrap it in more hackled silk. They don't have venom in their fangs, so they rely on their silk to hold their prey still.

What eats them and how do they avoid being eaten?

Known predators

Spiders in this family rely on their small size and camouflage colors. They often hide during the day.

How do they interact with us?

These little spiders probably help eat insect pests, but the don't have any strong impacts on humans. A few species are found around houses, and some people may consider this a nuisance.

Are they endangered?

No Hackled Orbweaver species are known to be in danger, but there are many species still unknown to science.

 
University of Michigan Museum of Zoology National Science Foundation

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BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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