Silk utilisation and defensive behaviour of Thiania , an iridescent jumping spider (Araneae: Salticidae) from Malaysia

Thiania demissa (Thorell) and an undescribed congeneric species were studied in nature and the laboratory. Thiania is a brightly coloured, iridescent salticid from Malaysian rainforests. Its bright markings may be eucryptic in the spider’s natural habitat. The spinning behaviour of Thiania was unusual for a salticid. It made a nest by binding a pair of green leaves together with strong silken rivets and rested, moulted, and oviposited in the narrow space between the bound leaves. Males cohabited with subadult females in the nest and mated after the subadult matured. Egg sacs were unusually flattened and densely woven for a salticid. At rest Thiania adopted a specialised posture that obscured the outlines of its body and appendages, and used a specialised leaping behaviour when approached by a potential predator. As a predator, Thiania seemed to use ambush more than active hunting. The behaviour of Thiania is discussed in relation to hypotheses concerning salticid evolution.