Mating: Usually takes place in spring and summer. Before mating the male transfer sperm from the genital opening under the abdomen, to the secondary sexual organs on the palps. This is done by depositing sperms on a small sperm web. The sperm is then absorbed it with the palpal organ, where it is stored until mating. Adult males now usually change their life-style completely to become wanderers in search of a female. Sexual dimorphism occurs in many species of spiders with the male being smaller than the female and often looking very different, To ensure e recognition by the female, the male uses various techniques to approach the female. In some the male has an intricate courtship ritual that involves the waving and raising of the palps. In some of the burrowing spiders, the male carefully approaches the female. He reveals his presence, by tapping rhythmically against the sides of the burrow. Courtship in most mygalomorphs is usually of short duration. The mating spur present on the front leg of the male is used to force open the jaws of the female. This prevents her from attacking during mating.
Egg-laying: Eggs are usually laid during summer. Egg laying does not necessarily take place directly after mating. In the female only lays eggs five months after mating. The number of eggs produced by the different spider genera varies greatly. Eggs are usually deposited in a waterproof egg sac or sac made of silk. The number of eggs per sac and the construction of the sac differ greatly between species. It frequently differs in size, shape and colour. In most families the egg sac is deposited in the bottom of the retreats.
The female tends the eggs and young. Newly hatched spiderlings are not always mobile after hatching. It was found in Ceratogyrus darlingii and C. bechuanicus of the family Theraphosidae that they only commence moving around approximately 50 days after hatching. In some genera the young spiders stay with the mother for a period of time
Ecdysis: As young spiders grow they undergo a number of moults. The first moult already takes place in the egg sac. A few days before moulting commences, the spider stops eating. First the skin under the carapace just above the coxae of the legs apart. The carapace then lifts off like a lid but remains attached at the pedicel. Next the skin of the abdomen tears at the side and the abdomen comes free. The legs, palps and chelicerae are pulled free from the skin with rhythmic movements and finally the spider pulls free. At this stage the spider is soft and defenseless and it takes a while before the new skin hardens.
In young spiders, moulting is completed within a few minutes but as the spider matures the process may last for an hour or more. Males usually moult fewer times than females. Araneomorphs spiders moult only until they reach maturity while a female mygalomorph spider lives much longer, can also moults after reaching maturity. If a leg is lost between moults, the spider is capable of regenerating a new one which appears after the next moult. Initially, the new leg is shorter and thinner than the others.
Dispersal: Since a large number of spiderlings emerge from the nest simultaneously, it can quickly lead to local overpopulation. Competition for available food and cannibalism frequently occur. Most of the mygalomorphs are more or less gregarious. Not much information is available on their dispersal. In most families they disperse by walking away from the mother’s burrow. If a favourable patch of ground is found around the burrow of the matriarch, the small spiderling will settle there. They aggregate in such a way that many burrows of juveniles are frequently found grouped around the burrow of the adult female (she is known as the matriarch in the cluster). However this differ between families and genera. In Ceratogyrus bechuanicus and C. brachycephalus Hewitt only small colonies are found scattered over a wide area while in some Pterinochilus species large numbers of burrows are usually grouped together in colonies that can count upto 106 burrows in 80 square metres.
Longevity: Most araneomorph spiders in the temperate regions live only one year or sometimes two. However, the mygalomorphs are renowned for their longevity and the atypids can life 7 years and the theraphosids over 20 years. As a rule only the female have a high life expectation. Because males have no role to play after the mating season, they frequently do not live as long as the females and dies a natural death a few weeks after mating. Apart from normal death owing to age, there are various other factors that can influence the longevity of a spider e.g. shortage of food and water, cannibalism, unfavourable habitats, adverse climatic conditions, fires, predation and destruction of their natural habitats by man.
Prey: Mygalomorphs prey on a variety of small animals such as:
insects: ants, beetles (e.g. tenebrionids), cicadas, cockroaches, Orthoptera (e.g. grasshoppers, locusts, crickets), Isoptera (termites), , Lepidoptera (mostly Saturniidae and Sphingidae, Hymenoptera (driver ants of the family Dorylidae).
arachnids: spiders, solifugids and scorpions.
millipedes small reptiles, amphibians and snails: frogs and lizards, snails.
Natural enemies: Spiders of all stages are attacked by a wide variety
of predators, parasitoids and parasites. They are a food source for a number of animals such as: birds, centipedes, reptiles (lizards, chameleons); insectivorous mammals (honey badger Mellivora capensis (Smithers, 1983), shrews, bats, mice and baboons); other arachnids such as scorpions, solifugids and spiders. Members of the spider family Palpimanidae are frequently found associated with trapdoor spiders and they may prey on them. They are also attacked by various fungi .
A number of insects are specialized predators or parasites of spiders: Hymenoptera (Sphecidae, Pompilidae, Ichneumonidae); dipterous parasitoids (Drosophilidae, Phoridae, Chloropidae); predators of the eggs (Sarcophagidae) and endoparasites (Acroceridae). Spiders have also endoparasites such as the parasitic nematodes of the family Mermithidae.
Defensive beviour: In the mygalomorphs different mechanisms are used to defend themselves against their enemies.
Venom: spiders make use of their ability to produce venom to defend them against predators. The mygalomorphs have fairly large fangs and would be able to deliver a nasty bite.
Urticating hairs: The release of urticating hairs from the abdomen of the spider is commonly found in the Theraphosidae of the New World. The hairs can be shed or insert by direct contact with potential predators by rubbing the region with urticating hairs. Hair-flicking is restricted to burrow spiders of the Aviculariinae and all members of the Theraphosinae, whereas contact urticating hairs are used only by arboreal spiders of the subfamily Aviculariinae. Urticating hairs are absent from the theraphosids of the Afrotropical Region.
Stridulation: When alarmed some members of the Theraphosidae produce a hissing sound sounding much like snakes, when setae on the chelicerae and palp are rubbed together.
Toxicity to man: little is known about the effect of the venom of mygalomorphs on man and animals. A species of Pterinochilus (Theraphoidae) from East Africa produces a venom with neurotoxic activities when tested on mice and guinea pigs. However compared to that of e.g. the black button the venom is less toxic. From Southern Africa painfull bites have been reported for Harpactirella lightfooti Purcell, a theraphosid species known from the Western Cape Province. The most venomous spider to man is the male of a mygalomorph, Atrax robustus of the family Hexathelidae. It is commonly known as the Sydney's funnelweb spider and 14 known deaths have been attributed to it. Another genus of the Hexathelidae is known from the Afrotropical Region but none from Southern Africa.
Family Dipluridae: female dorsal view
Family Idiopidae: male dorsal view
Family Idiopidae Galeosoma sp.
Family Ctenizidae Stasimopus sp.
Family Theraphosidae Ceratogyrus sp.
Fangs of a baboon spider (family Theraphosidae)