Flower spiders, often called flower crab spiders, are members of the family Thomisidaethat hunt on flowers rather than build classic prey-catching webs. They rely oncamouflage and ambush, lying in wait on petals and flower heads to seize visiting pollinators and other insects.
Ecology & Biology
Foraging strategy: mostly sit-and-wait predators, stationed on the centre or margin of flowers where bees, butterflies and hoverflies regularly land.
Colour change: some species (e.g. Misumena vatia) can slowly shift body colour between white and yellow to better match the host blossom.
Locomotion: as “crab spiders”, the front legs are longer and more robust; they often move sideways or diagonally, reminiscent of a crab.
Reproduction: females place egg sacs on flower stalks or leaves and guard them for a time; juveniles disperse onto nearby vegetation after hatching.
Identification
Body size: typically small; females about 4–10 mm, males smaller.
Shape: characteristic crab-like outline with enlarged front legs and a broad, flattened body suited to resting on petals.
Colour: often white, yellow, pale green or pinkish, sometimes with spots or stripes that enhance concealment among flowers.
Range & Habitat
Flower crab spiders are widespread across temperate and tropical regions worldwide. They inhabitmeadows, fields, woodland edges, gardens and shrublands, especially where blossoms and pollinating insects are abundant.
People & Safety
Medical relevance: of very low medical importance to humans. They are shy, seldom bite, and bites are usually minor if they occur at all.
Ecological role: by preying on pollinators and other small arthropods, they play a role in structuring flower‑visiting insect communities.
Observation: excellent subjects for macro photography; they should be observed rather than handled.
IUCN: most flower crab spider species are currently Not Evaluated (NE); this entry covers the group as a whole.
