ARACHNIDS | Overseas Collection

NB. these photos show some nice examples of stabilimenta in spider’s webs - a term used to describe the ‘decorations’ that are formed at the centre of some orbwebs by certain members of the Araneidae family Argiope genus. The first spider featured here is Argiope submaronica, but I’m not too sure about the other two. In Australia, Argiope keyserlingi is commonly known as the St.Andrew’s Cross Spider due the stabilimenta forming the arms of an X-shaped cross, very similar to that seen in the second photo. Obviously that’s not the same species, but the common name is still adopted. These ‘decorations’ are zig-zags of silk that form specific and consistent patterns. The name stabilimentum suggests a stabilising device, but certainly in respect of the British Wasp Spider, Argiope bruennichi, which typically has a band that stretches down, there are different opinions ranging from an attractive decoration that helps to attract prey, but possibly deters larger flying species such as small birds flying into it, to a strengthening feature that stops the web breaking up if large prey is thrashing about.