Arachnid
Heather Crab Spider
Thomisus onustusFemale heather crab spiders perch motionless among floral petals, shifting their coloration over several days between pure white, pink, and vibrant yellow to match host blossoms. Equipped with robust, crab-like forelegs, they ambush pollinators multiple times their size with a swift strike directed behind the head. During lean periods with few visiting insects, they adapt by feeding directly on nectar and pollen grains.
CamouflageAmbush HunterDimorphic
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & preyHoney bees, Hoverflies, Small butterflies
Predators
- Insectivorous birds
- Spider-hunting wasps
- Praying mantises
ThreatsHabitat loss from overgrazing, agricultural development, and pesticide usage
HabitatsHeathlands, dry grasslands, sunny scrub, and open meadows
Life span1–2 years
Classification
- FamilyThomisidae
- SpeciesThomisus onustus
Range data is not available yet.
Interaction riskLow
- Low
- Moderate
- High
- Very high
- Why interaction risk is low
- Harmless to humans; safe to observe closely on flowers.
Responsible observation
- Spotting: Scan sunny flowerheads of heather, thistles, and composite blooms for crab-like legs tucked beneath petals.
- Observation: Approach without casting direct shadows over the flower to avoid prompting a defensive freeze or retreat.
Host Plant (c) Andreas Rockstein, some rights reserved (CC BY-SA) · cc-by-sa
Prey Andreas Trepte / CC BY-SA 2.5 · cc-by-sa
Same Family (c) Wolfgang Jauch, some rights reserved (CC BY), uploaded by Wolfgang Jauch · cc-by
Same Family (c) Martin Scheuch, some rights reserved (CC BY), uploaded by Martin Scheuch · cc-by
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