Flower spider fact sheet | Field of Mars EEC

What are flower spiders?

Flower spiders are a group of spiders in the family Thomisidae. They are also called crab spiders because their front legs are long and strong and their legs curve forward in a crab-like way. Flower spiders are common across much of southern and eastern Australia, but they are often hard to see because they hide so well on flowers, leaves and stems. They are arachnids, so they have eight legs and two main body parts, not six legs like insects. Flower spiders are not dangerous to humans.

A flower spider.

What do flower spiders look like?

Many flower spiders have smooth, glossy bodies, a wide abdomen and short uneven legs. Their front two pairs of legs are much stronger than the back legs, which helps them seize prey. Some species are bright white or yellow, while others are green, brown, black or patterned so they can blend into leaves, bark or grass. Males are usually smaller than females.

A white flower spider waiting on a flower.

Where do flower spiders live?

Flower spiders live on flowers, shrubs, foliage, bark and in grassy plants. They are especially easy to miss on flowering plants because they sit very still and blend into the background. Around places such as Field of Mars Reserve, they are likely to be found in vegetation with lots of flowers and insects, including native shrubs such as wattles, grevilleas and banksias. Usually only one spider sits on a flower at a time unless it is mating, and many hide under petals or leaves at night.

Flower spiders live in vegetation in gardens and bushland settings.

What do flower spiders eat?

Flower spiders are ambush predators. Instead of building a web to catch food, they wait on a flower or leaf for an insect to come close. They catch prey such as honey bees, butterflies, flies and beetles with their spiny front legs, then bite it and use venom and digestive juices to break down the body so they can suck up the liquid food inside.

Flower spiders sit and wait for their prey.

What is the life cycle of a flower spider?

After mating, the female flower spider hides a soft, woolly egg sac inside a folded leaf or grass blade shelter and guards it. In some species she may even bring food to the developing young. When the spiderlings hatch, they stay in the egg sac until after their first moult. Then they leave and disperse, sometimes by walking through vegetation and sometimes by using silk to bridge gaps or float away on the breeze.

Flower spiders lay their eggs in a woolly-looking egg sac.

What adaptations do flower spiders have to help them survive?

Flower spiders have excellent camouflage. Some are white or yellow like flower petals, while others are green, brown or patterned to match leaves, bark or grasses. Their strong front legs help them grab prey quickly, and their habit of sitting very still makes them difficult for both prey and predators to notice. Flower spiders are active during the day, and vision is important for hunting in this group.

Flower spiders have amazing camouflage.

Flower spiders have strong front legs to help grab prey.

Why are flower spiders important?

Flower spiders are important predators in gardens, bushland and other habitats. By catching insects, they help control invertebrate populations and form part of local food webs. Like other spiders, they are a natural part of healthy ecosystems.

Flower spiders are important predators in bushland and gardens.

How can you help flower spiders?

You can help flower spiders by growing native flowering plants, protecting shrubs and garden plants, and avoiding unnecessary insecticide sprays. It also helps to leave some natural shelter in the garden and not pull apart folded leaves or flower clusters, because a female spider may be guarding an egg sac there. Watching carefully without disturbing them is one of the best ways to learn about these hidden hunters.

Flower spiders need healthy flowering plants and shelter.

Related fact sheets

More invertebrate fact sheets

• Invertebrate fact sheets – overview
• Arachnids fact sheet
• St Andrew’s Cross spider fact sheet
• Golden orb weaving spider fact sheet
• Huntsman spiders fact sheet
• Trapdoor spiders fact sheet

Habitats and ecosystems

• Shrub habitats fact sheet

• Tree habitats fact sheet

• Eucalypt forest fact sheet– explains the local bushland context.

• Field of Mars Reserve fact sheet – explains the local reserve and habitat diversity.

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