There is just a single species in Britain belonging to the genusMisumena(2). As the common name suggests, it is reminiscent of a crab, with its wide, flattened body form and habit of sitting with the first pair of legs held apart (3). This spider has the remarkable ability to alter its colour to match its background, usually a white or yellow flower, allowing it to become beautifully camouflaged (3). The sexes are different in appearance; females vary in colour from white to pale green or yellow, depending on the background. They tend to have two pairs of bright red spots on the abdomen, but these may be fused to form red lines or even entirely missing. Males are much smaller in size than females and have more slender greenish white abdomens that feature brown stripes (2).
This species does not spin a web to catch its prey. Instead it lies in wait on flowers and vegetation for a suitable prey species to visit and swiftly ambushes the insect (2)(3). It then injects venom into the prey with the slender fangs (3).
Males deposit a drop of sperm which is taken up by specialised leg-like appendages known as ‘palps’. During copulation, the sperm is passed to the female’s reproductive organ (the ‘epigyne’). After mating, the female lays the eggs, folds a leaf over them and spins a protective silk cocoon around the folded leaf. She will then cease to feed and stands guard over the eggs for around three weeks, after which the eggs hatch and the female dies (3).
In arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree (but not visibly in most spiders). In crustacea (e.g. crabs) some of the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).
A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
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