#4 A Spider and its Offspring

Have you ever stumbled into a huge spider's web amongst the shrubbery or behind the shed and had to fight your way out of the clutches of the silk?

This common garden beauty is the likely owner of that web

As its common name suggests, the Golden Orb-weaver Spider, Nephila edulis, spins an orb web of golden silk. The extensive semi-permanent web is remarkably strong and makes a formidable sight when several spiders overlap webs creating a dense and almost impassable barrier. Walking into a mass of Golden Orb Spider webs either in daylight or the dark is enough to make even the toughest Aussie bloke squeal like a girl (now, correct me if I'm wrong please) .

A luckless cicada is no match for the strength of a Golden Orb-weaver's web

But the Golden Orb really is a gentle giant. Despite a mature female's body size of up to 3cms (excluding legs), these spiders are not aggressive and will dart to the top of the web if disturbed. Being diurnal, they spend the day in their web protected from birds and wasps by a network of subsidiary threads safeguarding the main web.

Moulting

A spider must shed it's external skeleton in order to grow. This is a complex process whereby enzymes dissolve the layer between the skin and the rest of the body, and a new skin begins to form below the old one. The nerves stay connected to the sensory organs on her old skin so that she is not deprived of essential signals from the sensory organs on her legs.

The skin starts tearing at her jaws and the crack enlarges to the abdomen. When the skin has become completely loose the spider falls out of her old skin.

A Golden Orb limp from having just moulted hanging below her old skin with a male lurking above

Spiders can often be seen with one or more missing legs, but after moulting these lost legs regenerate. Isn't nature amazing!

Mating

Spider sex is a lot more intriguing than one might initially imagine! While the female Golden Orb-weaver Spider's body measures over 20mm, the male is a mere 5mm. If you take into account the female's fettish to feast on her suitor once he's served his purpose, then the male appears to be courting danger. But like most males a courting, he can be quite resourceful.

The male Golden Orb lurks on the perimeter of the female's web feeding on left-overs, waiting for a mating opportunity. He then begins his mating sequence after the female has caught prey, therefore limiting the likelihood of becoming the female's next meal.

Spiders have a pair of feelers (or more correctly, pedipalps, or palps) located on the jaw. The male's palps have a bulb on the end that is used to hold sperm to be injected into the female. First, the male must eject semen from his genital opening under the abdomen then suck it up into his palps ready for insertion into the female.

In the image below you can see the swollen bulb on the tiny male's palps. Compare the shape of the male's palps to the female's palps in the third picture. Also in the image below, the male is hovering at the female's genital opening while she is limp from moulting and looks suspiciously like he is taking advantage of the incapacited female. Notice also, the screw-like extension on the end of the palp that is used to gain access to the female genital opening.

A male possibly attempting to mate with an incapacitated female

The female will wrap her eggs in a sac of golden silk

After several months the Golden Orb hatchlings will emerge from the egg sac and balloon away on the breeze. I first noticed the spiderlings in the image below emerging in June from an egg sac that was deposited in March. The tiny Golden Orb-weavers re-entered the sac and emerged again in August. They eventually disappeared in September after a total of six months.

Golden Orb hatchlings are less than 1mm in diameter

The hatchlings then must endure the hazards of predators and weather. Hopefully some will survive to grow and repeat the process. Since observing and researching these awesome spiders hanging in their shiny webs in my backyard, I have come to respect them and their complex lives.

A young female Golden Orb-weaver displays beautiful colouration that will fade to a silky light brown as it matures

Golden Orb weavers have relatively poor eyesight as they do not rely heavily on sight for catching prey. They are reluctant to bite and are not considered very toxic.

Perhaps next time you see one of these impressive spiders hanging overhead you will also appreciate their place in the environment - they're not as scary as they might first appear.