Quick answer: “Flower crab spider” is a common name for crab spiders (family Thomisidae) that hunt on flowers instead of building webs. In North America and Europe the name usually means Misumena vatia, also called the goldenrod crab spider, whose adult females can slowly switch between white and yellow. In Australia, “flower spider” is used more loosely for several flower-dwelling thomisids, including the white crab spider Thomisus spectabilis.
What Is a Flower Crab Spider?
Crab spiders get their name from the way they hold their legs: the first two pairs are long, strong and spread out to the sides, so the spider can shuffle sideways and grab prey much like a crab. The family Thomisidae includes many ground- and bark-dwelling species, but the ones people notice most are those that sit on open flowers, often matching the petals closely enough to be overlooked.
Because the name is informal, it does not point to the same spider everywhere. Before matching a photo to a species, it helps to know where the spider was found.
| Region | What “flower crab spider” usually refers to | Notes |
|---|---|---|
| North America | Misumena vatia (goldenrod crab spider) | Other flower-visiting crab spiders occur there too, such as Misumenoides formosipes (Canada and USA) and Mecaphesa asperata, which was formerly placed in Misumenops. |
| Europe, including the UK | Misumena vatia | The British Arachnological Society uses “Flower Crab Spider” for this species. |
| North Africa and Asia | Misumena vatia where it occurs | Its recorded range runs from Morocco and Europe across Russia and Central Asia to China, Korea and Japan. |
| Australia | Flower-dwelling thomisids in general (“flower spiders”) | Misumena vatia is not part of the Australian fauna. Common flower dwellers include Thomisus spectabilis, whose range extends from India to Australia. |
The rest of this guide focuses mainly on Misumena vatia, the best-studied flower crab spider, and points out where Australian flower spiders differ.
Flower Crab Spider Quick Facts (Misumena vatia)
| Scientific name | Misumena vatia (Clerck, 1757) |
|---|---|
| Family | Thomisidae (crab spiders) |
| Other names | Goldenrod crab spider, flower crab spider |
| Body length | Females about 9–11 mm; males about 3–4 mm (body length, not leg span) |
| Range | North America, Morocco, Europe, Turkey and the Caucasus, Russia, Central Asia, China, Korea and Japan |
| Habitat | Flower-rich meadows, gardens, field edges and woodland margins |
| Web | None for catching prey; it ambushes insects on flowers |
| Main prey | Flower visitors such as bees, flies and butterflies |
| Known for | Adult females changing between white and yellow over several days |
How to Recognize a Flower Crab Spider
No single feature is enough. White or yellow color in particular is weak evidence, because several unrelated spiders can look pale. Use a combination of clues:
- Leg posture: the first two pairs of legs are clearly longer and thicker than the back two and are held open to the sides, ready to close on prey.
- Body shape: a short, rounded to slightly flattened abdomen that is often wider toward the back.
- Where it sits: on the face of an open flower or a flower head, usually still for long periods. It does not sit in a web.
- Size: adult females of Misumena vatia are around 1 cm long. Males are only a third of that size and are easy to miss.
- Region: check the table above. A flower crab spider photographed in Australia is not Misumena vatia.
Females and males look very different
In Misumena vatia, the two sexes are so unlike each other that they are sometimes mistaken for separate species.
- Adult females are white, cream or bright yellow. Some have a pair of red streaks or spots on the sides of the abdomen. The legs are pale, matching the front part of the body.
- Adult males are small, with a dark brown front body section, a whitish abdomen marked with dark stripes, and dark-and-light banded front legs.
- Juveniles, and some adult females, have a chalky white abdomen.
How the Color Change Works
The color change is real, but it is slow. It is not the quick switch seen in a chameleon or an octopus.
In Misumena vatia, it is described in mature females. The British Arachnological Society notes that the change takes several days, passing through cream shades before reaching bright yellow, and that it can be reversed. The white color comes from reflective guanine crystals under the skin. The yellow comes from a pigment the spider produces and later breaks down again.
Research on a related European species, Thomisus onustus, found that background color was the main trigger: spiders kept against yellow turned yellow, and those kept against white turned white. The same study reported that earlier work on Misumena vatia found the change toward yellow to be noticeably slower than the change back to white.
Not all flower spiders change color, and not all of them try to match the flower. Some Australian flower spiders have green to brown legs and a patterned abdomen that blends into leaves and mixed backgrounds rather than a single petal color.
How Flower Crab Spiders Hunt
Flower crab spiders are sit-and-wait predators. They take up a position on a flower, keep very still and let insects come to them. When a bee, fly or butterfly lands within reach, the spider closes its front legs around it and bites, usually near the head or neck.
Venom works quickly to subdue the prey. The spider then releases digestive fluids and sucks out the liquefied contents. Because it punctures rather than chews its food, what is left often looks like an intact, empty insect. Prey can be much larger than the spider itself, including bumblebees and butterflies.
A different trick in Australia
Not all flower spiders rely on blending in. A study published in Nature found that the Australian white crab spider, Thomisus spectabilis, is hard for people to see on white daisies but stands out to honeybees because its body strongly reflects ultraviolet light. Honeybees actually chose daisies with a spider on them more often than empty ones. The spider seems to exploit the bees’ attraction to contrasting flower markings rather than hiding from them.
Where Flower Crab Spiders Live
Misumena vatia lives in open, sunny places with plenty of flowers: meadows, gardens, field margins and grassy or scrubby woodland edges. It is often reported on white and yellow flowers such as daisies and goldenrod, which is where its common name comes from.
In Britain, the British Arachnological Society describes it as a southern species, largely absent from the north. There, males usually mature in May and early June, and females from mid to late June, so adults are most noticeable in summer.
Australian flower spiders are active by day and are often found on native flowering shrubs such as grevilleas and wattles. Many settle on a single flower and stay until the petals fade before moving on. At night they tend to shelter under petals or leaves.
Life Cycle
Males of Misumena vatia find females by following their silk draglines. After mating, the female wraps her egg sac inside a rolled or folded leaf and stays on guard. The young hatch after about three to four weeks, spend the winter as juveniles, and mature the following year. Females can live about two years.
Guarding the egg sac is common among flower spiders, and many Australian species also hide their eggs in a folded leaf or grass-blade shelter.
Social flower spiders
Some Australian crab spiders break the usual solitary pattern. In southern Australia, members of the genus Australomisidia (formerly placed in Diaea) live in family groups inside nests made from eucalypt leaves. The best-studied example, Australomisidia ergandros, is recorded from New South Wales, the Australian Capital Territory, Victoria and Tasmania; its nests usually hold one adult female and her offspring, and the group keeps enlarging the nest by adding more leaves.
The Australian Museum describes how a female in these social species starts with a single curled leaf, lays one egg sac, and brings large prey such as beetles and wasps back for her young. If food runs short, the young may eventually feed on their mother.
Are Flower Crab Spiders Dangerous?
Flower crab spiders are not considered dangerous to people. The Australian Museum describes flower spiders as harmless to humans, and the University of Minnesota Extension notes that the goldenrod crab spider does not harm people. Their venom is suited to subduing insects, and they spend their time waiting on flowers rather than seeking contact with people.
As with any spider, it is sensible not to handle one roughly. If someone has a strong reaction after any suspected bite or sting, or symptoms that spread or get worse, they should get advice from a doctor or a local poison center. For a broader look at spider risk, see our spider bite and danger guide.
Spiders Commonly Confused With Flower Crab Spiders
- Other crab spiders on flowers: several thomisid genera use flowers. In North America these include Misumenoides and Mecaphesa. Telling them apart from Misumena often needs a sharp, close photo of the body markings and front of the head, and sometimes an expert check.
- Bark and ground crab spiders: many members of the same family are brown, grey or mottled and live on bark, in leaf litter or on the ground. They have the same crab-like leg posture but not the pale flower-matching colors.
- Jumping spiders on flowers: jumping spiders also hunt without webs and may sit on flowers, but they have a pair of very large forward-facing eyes and move in quick, sudden hops rather than waiting motionless with their front legs spread.
If you are unsure what you have found, our spider identification guide walks through the clues that matter most, and the spider types section covers other spider groups.
Are Flower Crab Spiders Good or Bad for Gardens?
They are a natural part of a flowering garden. Like most spiders, they help keep insect numbers in check, which is part of why spiders are important in ecosystems. They do also catch pollinators, including bees, so their effect on any one garden is mixed. A few spiders on flowers are not a sign of a problem, and they need no control.
Frequently Asked Questions
Do flower crab spiders make webs?
No. They use silk for draglines and to protect egg sacs, but they catch food by ambush, not with a web. You can read more about how different spiders hunt in our spider behavior section.
How fast can a flower crab spider change color?
Slowly. In Misumena vatia, the change between white and yellow takes several days and is seen in adult females. A spider that has just moved to a different flower will not match it right away.
What do flower crab spiders eat?
Mostly insects that visit flowers, such as bees, flies, butterflies and beetles. For a wider view of spider feeding habits, see our spider diet section.
Is the goldenrod crab spider the same as the flower crab spider?
In North America and Europe, usually yes: both names are commonly used for Misumena vatia. In Australia, “flower spider” refers to a wider group of crab spiders, and Misumena vatia does not occur there.
References
- World Spider Catalog (2026). Misumena vatia (Clerck, 1757); Thomisus spectabilis Doleschall, 1859; Thomisus onustus Walckenaer, 1805; Australomisidia ergandros (Evans, 1995); Mecaphesa asperata (Hentz, 1847); Misumenoides formosipes (Walckenaer, 1837). Natural History Museum Bern. wsc.nmbe.ch
- Oxford, G. & Smith, H. Flower Crab Spider, Misumena vatia. Advancing Arachnology Factsheet 12. British Arachnological Society. britishspiders.org.uk
- Gray, M. Flower Spiders. Australian Museum. australian.museum
- Heiling, A. M., Herberstein, M. E. & Chittka, L. (2003). Crab-spiders manipulate flower signals. Nature, 421, 334. nature.com
- Llandres, A. L., Figon, F., Christidès, J.-P., Mandon, N. & Casas, J. (2013). Environmental and hormonal factors controlling reversible colour change in crab spiders. Journal of Experimental Biology, 216, 3886–3895. journals.biologists.com
- González-Tokman, D., Ruch, J., Pulpitel, T. & Ponton, F. (2014). Cuticular antifungals in spiders: density- and condition dependence. PLoS ONE, 9(3), e91785. ncbi.nlm.nih.gov
- University of Minnesota Extension. Goldenrod crab spider. extension.umn.edu
