Behaviour and Life Cycle of the Portia Spider

The portia spider is one of the most incredible spiders known to man. This 6-10mm long jumping arachnoid comes in 15 different types and is mainly found in Australis, Asia and Africa. What sets the portia apart from other predatory animals, is the sheer intelligence behind the predatory skills this tiny creature possesses. Its behaviour has been closely studied and some remarkable facts discovered. The portia spider is not just intelligent, but is cunning too and has a well-structured plan behind its hunting motives. Preying on other spiders in preference to insects, the portia's scheming actions are deployed to trap and kill its prey in very imaginative ways, thereby making it one of the most effective serial killers in the world.

Portia spiders have an awkward gait, unlike scurrying spiders, they move in a juddering, robotic fashion. They can build webs of their own, but are usually found skulking around the webs of other spiders. Resembling a dead leaf when still and with very good eyesight, (most spiders cannot see very well) part of the luring strategy of the portia is to pluck on the web of their prey, to replicate the movement of freshly-caught insects. This tricks the other spider into thinking it has just caught a tasty meal and it is lured towards the waiting portia. However, if their prey panics, sensing that the vibrations on the web are from a predator rather than an insect, the portia will back off and wait, often returning via a circuitous route, hours later, to make another attempt at the kill. Portia use a deadly venom to kill their prey.

The portia also uses nature to disguise movement when stalking and hunting. By moving in time with the wind or breeze, the portia can trick its prey into thinking the vibrations of movement on a web are coming from a sudden current of air, rather than a predator.

In studies and analysis of the behaviour of the portia, six different factors in their hunting have been identified. These include, taking on board information, homing in on individual hunting strategies, building a picture of the situation, retaining information and solving problems when things don't go according to plan. Finally, the portia spider can feign communication with its prey, by mimicking the other's mating pattern, as part of the lure to kill.

Unfortunately for the male portia, their life cycle tends to be cut short due to the cannibalistic behaviour of the female in all but one of the sub-species. The portia has different mating styles to other jumping spiders. The male puts on a mating display to attract the female. The female vibrates the web in response. When the male makes sexual contact, the female may spin and drop a line and they mate in mid-air, or they can mate on the web.

If the male is killed before mating has finished, his sperm is removed by the female before he is eaten. If copulation occurs before the male is eaten, his sperm are kept for fertilisation and the life cycle of the portia begins again when the young are born from the eggs the female lays. The vast majority of male portia are killed during mating. The typical life cycle span for a portia spider is just 1-3 years but during that relatively short time, the portia will have triumphed many, many times over every other kind of spider in its environment.