The “typical” Orb-weaver Spiders (family Araneidae) are the most common group found in gardens, fields and forests. Their common name is taken from the round shape of this typical web. Orb-weavers have eight similar eyes, legs hairy or spiny and no stridulating organs. The orb-weavers include over 10,000 species and make up about 25% of spider diversity.
The backyard master-builders that work by night and rest by day. Garden Orb-weavers are harmless spiders and are fascinating to watch as they construct their intricate webs. The web is a classic round ‘orb’ web, which is suspended in a position that is likely to be a flight path for insects.
One thing that often perplexes people is how they get their web from one place to another. The answer is simple – the air carries it. When the spider is ready to build a web, it moves to a high vantage point, puts the tip of its abdomen in the air, and releases a steady flow of silk from its spinnerets. The silk is so light that the slightest breeze will carry it, and it will float on the wind until it snags against a solid object. The spider continues to do this until is has a line attached to a suitable site. Once the spider has this initial line in place, it can move out along it to build the rest of the web.
Unlike some other spiders which construct a web and stay in it both day and night, Garden Orb-weavers remove the web at dawn each day, and construct a new one each night. The reason for this is predator avoidance.
These spiders would be easy prey for hungry birds, so they have developed the hide-by-day strategy. Although the main ‘orb’ part of the web is gone during the daylight hours, some of the structural lines are often left in place, and the spider usually shelters at a point where these meet a tree, house or fence.
The camouflage of the Garden Orb-weavers is excellent when they are in ‘day-time’ mode; their compact, mottled brown bodies and tightly folded legs look just like a bump on a branch.
At night these spiders take on a completely different look, spreading their legs out in the ‘ready’ position as they sit in the middle of their web. The upper joints of their legs (which are hidden during the day) are exposed and are usually red in colour.
Their web is designed to catch flying insects, and the most common at night are moths and beetles. When prey strikes the web, Garden Orb-weavers move like lightning – they must. If they give a struggling insect time to thrash around in the web, it will usually free itself, so speed is of the essence. Once the spider reaches the prey it will wrap it quickly with copious amounts of silk in bandage-like form, before biting it and returning the central hub of the web.
Like all spiders, Garden Orb-weavers can only eat liquid food, so the indigestible solid parts of their insect prey are discarded and dropped to the ground below the web.
I found all of this information on the web…I thought it was just fascinating for such a little spider! Pretty scary-looking creature, huh?