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Last Updated on Friday, 23 May, 2025 11:41:17 PM

Spiders of Borneo > Family Thomisidae 蟹蛛科 > Genus Runcinia 鋸足蛛屬 > Runcinia affinis 近緣鋸足蛛

Family: Thomisidae
Subfamily: Thomisinae
Genus: Runcinia

Runcinia affinis
近緣鋸足蛛

Crab spiders are easy recognizable if you tease them. They widen their legs and move side ways like a crab. The size of these spider genus varies between 4 - 10 mm.

In some genera, there is a great disparity between the male and the female. The Philodromus dispar as shown below is a nice example. The male is completely different from the female.
The females usually stand guard with their egg sacs. The egg sacs are fastened to the vegetation and are usually flat.
Flower Spiders are also called Crab Spider. They are small to medium size with colour of green, yellow, white brown and grey.
Crab spiders are not hairy.

Flower spiders sit on flowers waiting for prey to come along, then ambush them and suck their juices out, as is happening above. The Flower Spider shown below can change its ground color at will, helping it blend in with the flowers among which it is hiding. Flower Spiders inject their prey with a potent toxin that disables insects much larger than themselves. Flower Spiders are part of a larger group of non-web-spinning spiders known as Crab Spiders, of which about 130 species are known just in North America. Crab Spiders hold their legs crablike and walk forward, backward or sideways like crabs.

They are not active hunters and make more use of the camouflage techniques than other hunting spiders. The colour of the spider is adapted to the hunting terrain they use. They remain unmoved until the prey arrives and catches it. They are usually found on flowers or leaves and and will stay there for days.

The Flower Spider hides on flower or branch, front four legs ready to seize a visiting insect. Their abdomen is white and yellow in colour, well camouflaged when it sits on flower.

Crab-like legs

Legs are held in crab-like position and can move forward, backward or sideways.
Their front pair of legs are spiny and pointed to the front, prepare to attack their prey.
This Crab spider is protecting her eggs.
Most Crab Spider females guard their egg sacs but die before the eggs hatch.

Crab spiders' median eyes are movable independently
Crab spiders have eight eyes, in two rows of four, near the front edge of their head.
They can move their median eyes independently.