Feeding and diet

Scorpions are nocturnal hunters, feeding mainly on arthropods such as beetles, cockroaches, spiders, slaters, centipedes and millipedes. One Australian species, Isometroides vescus, is specialised to feed solely on burrowing spiders, especially trapdoor spiders, invading and often occupying their burrows. Many scorpions are lie-in-wait ambushers that forage at or in the vicinity of the burrow entrance (eg Urodacus spp.), but some, notably bark and litter dwellers (eg Lychas spp.), are more active foragers.

Ground vibrations caused by moving prey are sensed both by slit-like tarsal sensory organs on the scorpion's legs and vibration sensitive tarsal hairs. The clawed grasping pedipalps are used to hold the prey while the scorpion stings or crushes it. The scorpion digests its prey by pouring digestive juices onto the prey and breaking it up with its jaws. The hard outer body casings are discarded. The main predators of scorpions are carnivorous marsupials, rodents, lizards, nocturnal birds, centipedes and other scorpions.

Other behaviours and adaptations

Scorpions are arachnids, which means that they are related to animals such as spiders, ticks, mites and harvestmen. Arachnids are characterised by possessing four pairs of legs and a body divided into two parts - the cephalothorax (containing the mouthparts, eyes, pedipalps and legs) and the abdomen (containing the reproductive and digestive organs). One particular group of arachnids that can closely resemble scorpions is known as Pseudoscorpions. These possess large grasping pedipalps, but lack the characteristic tail and sting of true scorpions.

Breeding behaviours

Males and females find each other by vibration, scent and touch. During mating, the sensory pectines under the body are used to find a suitable place for the male to deposit his sperm parcel - the spermatophore. The male and female then perform a mating dance above the spermatophore, with the female being wrestled into position over it in order to draw it up into her genital pore. The fertilised eggs develop inside her body, and she then gives birth to live young. She carries the pale young scorpions on her back for the first few days or weeks, until they are strong enough to become independent. The young then disperse to find food and shelter. Scorpions take a long time to reach maturity, moulting frequently (up to five or six times over two to six years) in order to grow, and may live for two to ten years. Some have been recorded as living up to 25 years.

Danger to humans

Australian scorpions can give a painful sting which can cause inflammation and pain for several hours. First aid for a sting is to apply a cold pack and to seek medical aid if pain persists. It is also a good idea to try to catch the scorpion and have it identified. The scorpion usually seen in houses is the small Marbled Scorpion.



To avoid being stung by a scorpion, wear good gloves and shoes in the garden and don't leave things lying around on the floor in the house or garage. Reduce invertebrate habitat by covering compost and garbage, and cleaning up building materials around the house. Scorpions are great pest controllers in the garden, so if one is found in the house, collect it carefully in a jar and remove it to a safe distance, rather than killing it.

References