Goldenrod Crab Spider

Misumena vatia is one of about 2,000 species in family Thomisidae — the crab spiders, named for their wide flattened bodies and the way they walk sideways like crabs. M. vatia is one of the few spiders that can change color: females shift between bright white and golden yellow over a 1-3 week period to match the flower they are hunting from, by either secreting xanthophyll-derived liquid pigment into the cuticle (yellow phase) or excreting it back to the gut (white phase). The mechanism is hormonally controlled and triggered by visual cues from the petal background. Crab spiders do not build webs; they sit motionless on flowers with their two long pairs of front legs spread wide in a 'crab' posture, waiting to ambush pollinators. The bite delivers a fast-acting venom that paralyzes prey within seconds — crab spiders routinely kill honey bees, bumblebees, butterflies, and wasps several times their own body weight. Despite the venom, the bite is harmless to humans (small jaws, mild dose). The species is found across temperate North America, Europe, and Asia. Other notable Thomisidae species include the giant crab spiders (genus Heteropoda, Asia, leg span 30 cm) and the bark crab spiders (Bassaniana, perfectly camouflaged on tree bark).