The Mygalomorphae are a diverse group of spiders and most species (except the Microstigmatidae) live in silk-lined retreats. The retreats could be either vertical burrows or chambers made under rocks or under the bark of trees. The retreats can be left open or be closed by a trapdoor. Extensions of the entrance are frequently found in the form of lids, signal threads, collars, turrets or catch webs. This structure extend the range of the spider and help the substrate vibration receptors located on the palps and legs of the spiders to detect prey. Most of the prey is usually captured at or close to the entrance of the retreats. The construction of trapdoors and other structures around the retreats have evolved many times independently.
The Microstigmatidae are the only free-running mygalomorph spiders in Southern Africa that do not living in a burrow or web. Mygalomorphs are usually nocturnal and hide during the day in their retreats. At night some species wander around in search of food while most of the burrow living spiders lay and wait for prey in the entrance of their retreats.
against predators and parasites
for the eggs and developing spiderlings in the brood chamber
during the moulting process
while intercepting or ambushing prey
during inactive periods, especially during winter
against flooding as the silk used is waterproof
against field fires when spider withdraw deep into the burrow
against thermal stress as temperature and humidity stay relatively stable in the burrow
against fungal and bacterial attacks due to the antibiotic properties
Checklist of species
Spider Research Centre