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Web decorations, sometimes termed ''stabilimenta'', are conspicuous silk structures included in their webs by many species of orb-web Spider . There is much controversy surrounding the function of these structures. Some people believe that they provide protection to the spider by either camouflaging it or making it appear larger. Another theory is that they make the spider visible and therefore animals such as birds are less likely to damage the spider’s web. (Herberstein et al. 2000; Bruce 2006). A more recent theory is that web decorations attract prey by reflecting Ultraviolet Light (Craig & Bernard 1990). Light in the ultraviolet part of the spectrum is known to be attractive to many species of insects (Craig & Bernard 1990). Many other theories have also been proposed such as thermoregulation, stress, regulation of excess silk and web stabilization (the source of the term "stabilimenta"). Although web decorations are common in a number of spider species in the families Araneidae , Tetragnathidae and Uloboridae , they are probably best known from spiders of the genus '' Argiope '' that includes a number of species known as the ''St Andrew's Cross spider'', so named because of the characteristic cross-shaped web decoration. However, spiders in this genus also construct web decorations as a vertical line and juveniles commonly construct disc-shaped decorations (Bruce & Herberstein 2005). While the most conspicuous and well-studied decorations are constructed entirely of silk, some spiders combine silk with other items such as egg sacs and debris. It seems likely that these decorations camouflage the spider, thus providing protection against predators (Eberhard 2003). However, one interesting case occurs in some species of the golden orb spiders in the genus '' Nephila ''. These spiders commonly attach lines of uneaten prey items to their webs. Recent studies have shown that these items help the spider to attract more prey (Bjorkman-Chiswell 2004). An alternative theory has been put forward that the purpose of the stabilimentum is to attract the male of the species to the web when the female is ready to reproduce. A limited study (unpublished - Tickner 1992) carried out in the Calahonda area of Spain in the summer of 1992 showed that there was a positive correlation between the presence of a male in the webs of ''Argiope Lobata'' and the presence of a stabilimentum. SEE ALSO REFERENCES
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