Bark Spiders are orb-web spiders. They construct webs up to 1.5 meters in size stretching from tree to tree. They are very well camouflaged spiders mimicking the colour and shapes of bark brilliantly. Bark Spiders are nocturnal. This shot was take just before the sun was about to set.
There are four species report from southern Africa namely: Caerostris corticosa, Caerostris mitralis, Caerostris sexcuspidata and Caerostris vinsonii.
Caerostris corticosa occurs away from forest and appears to be an arid to fynbos species found in Botswana, the Northern and Western Cape with a record for Pretoria. At Grootvadersbos Nature reserve it was found to be common in burnt fynbos with webs spread between dead branches about 1.5-2metres above the ground. No spiders were found in the adjacent forest some 100-200metres away. It was not as common in unburnt fynbos. The egg sacs has a yellowish tinge and the spiderlings are black. The adult females were all a dark grey and no males are known.
Caerostris mitralis is found in Mozambique and Kwazulu/Natal in South Africa.
Caerostris sexcuspidata, although nocturnal, can be found on her web in shaded forested areas during the day. This is the most widespread species occurring south of the 5° North (central and east Africa) It is the common species in South Africa and the species with the most variations in abdomen shape.
Caerostris vinsonii occurs from central Africa to Botswana, Mozambique and Kwazulu/Natal in South Africa.
This information was courtesy of Norman Larsen.