World-wide web

For most people the stereotypical spider web is the flat wheel-like structure seen suspended between bushes or on fences (pictured left). These are constructed by a group of spiders known as Orb-weavers, in English the word ‘orb’ infers ‘roundness’. These spiders are found all over the world. As with any large group of fauna there are no strict rules – not all orb-weavers build orb-shaped webs and there are some spiders that are not orb-weavers that do build orb webs (it’s not the web that defines the spider!).

The orb-weaver builds the web by floating silk in the wind from one point to another. From the middle of that strand it repeats the process. These strands radiating from the centre are not sticky and the spider uses these to navigate around the completed web. Once the radial structure is completed the spider walks around the web laying concentric circles of ‘sticky’ silk with which it catches prey. Many such spiders are nocturnal. During the day orb-weavers will sit camouflaged in the vegetation (see photo below). At dusk they will consume or dismantle the existing web and build a new one for the night.

Slender Leaf-shaped Orb-weaver (Araneus talipedatus)

Like all spiders orb-weavers have eights eyes distributed as two rows of four, one row above the other. For orb-weavers the middle two eyes of both rows form a tight square configuration with the outer eyes being spaced further apart.

Orb-weavers exhibit a large variety of shapes, sizes and colours. In suburb gardens, Golden Orb-weavers (Nephila sp.), pictured right, are commonly seen orb-weavers. Those who go bushwalking during summer will be familiar with the webs of Spiny Orb-weavers such as the Australian Christmas Jewel Spider (Austracantha minax), below, which appear to cover every bush.

Orb-weaver webs are usually vertical and the spider sits with its head facing down. The male is much smaller than the female and mating is initiated by the male tapping the web to signify its presence – the arachnid form of Tinder!