Subject: Australian Inquiry
Location: Dorrigo, New South Wales, Australia
January 28, 2016 7:43 pm
Im writing to you from Australia, the East Coast NSW. I have found this nest on my fathers property and its got us all puzzled. (Obviously, otherwise I wouldn’t be writing to you for help!)
Its a group of small nests/cocoons (?) suspended in an olive tree. you can see by the photo that there are seven sub-dwellings dangling down, each approximately 5-7cm (2-3″) and what you can’t quite see from the picture is that there is a egg/sphere-shaped object tucked up in the mass of leaves that are all swathed in that goldy-orange web. there has been no movement noticed to or from the nests, but over the 4 weeks we have noticed that a pinprick hole appeared overnight in only one of the seven nests top…(perhaps a visiting parasite, it didn’t look like an obvious entry/exit hole for the resident in question.) Other details are the 7 nests are hollow/hard paper sounding constructions. the web has carcasses of beetles and flies stranded in it – seemingly in a certain area above which indicates they have been eaten by a resident… thats about all the information I have… I do hope you can help out, curiosity is peaked as we wait and watch!
Signature: Kind Regards, Naomi Drage
We are really enjoying researching your request. Our initial impression that these resembled the Egg Sacs of Orbweaver Spiders proved to be correct when we discovered the Australian Museum page on the Magnificent Spider, Ordgarius magnificus. According to the Australian Museum site: “Very little is known about the courtship and mating of Magnificent Spiders, but once egg development starts, the female’s abdomen swells up quite remarkably. She constructs a series of spindle-shaped egg sacs over several nights, and each one is filled with about 600 eggs. The egg sacs are attached to a branch, and may number up to seven. They are often parasitised by wasps and flies. The mother spider usually dies off over winter. The baby spiders emerge in late winter to early spring and disperse by ballooning.” The site also notes: “During the day, the Magnificent Spider hides in a retreat made by binding leaves together with silk. Preferred trees include natives such as eucalypts in dry or wet sclerophyll forests, but these spiders are also found in suburban gardens. Often the spider’s characteristic spindle-shaped egg sacs are hanging near the retreat.” The retreat is evident in the upper right hand corner of your excellent image. Butterfly House also has some wonderful images and notes: “These spiders are quite amazing. They catch their prey by creating a line of silk with a sticky blob on the end, then swinging it round and round. They emit the pheromones of some female moths to attract the male moths within range of their bolas, catching the moths rather like the Incas hunted game and the gauchos of Argentina catch their cattle.” The Find a Spider Guide has a marvelous image of the Magnificent Spider and notes: “The two yellow cones and red marbling on the dorsal surface of the abdomen of this spider are distinctive. Also very useful for identification purposes are the egg sacs. These are very large (about 5 cm long) and spindle-shaped, and hang in groups of about five.” Your especially fecund female has produced seven egg sacs. Thanks so much for providing our site with this wonderful posting for our archives. Perhaps you will be able to get an image of the Spider herself. She is undoubtedly the “egg/sphere-shaped object tucked up in the mass of leaves that are all swathed in that goldy-orange web” you mentioned. The information provided on Arachne.Org may help you get that image which may require a flash on your camera. Here is that information: “These spiders are active at night, with a simple web in trees or tall shrubs, rarely less than 2 metres above the ground. Their presence is usually indicated by a cluster of large, brown egg sacs hanging among foliage. The egg sacs are conspicuous, up to 5 cm long – many are targeted by flies and wasps that parasitise spiders’ eggs. Up to 9 sacs may be made by a spider in a season, each with several hundred eggs. The male spiders mature within the egg sac, emerging with fully functional mating organs. At night the female spins a trapeze line from twigs above an open space in the branch or foliage. She hangs from this trapeze and spins into the space a short, single line of silk with a large droplet of very sticky silk, the bolas, at its end. The upper end of the line is held by the female’s second leg. The spider emits an airborne pheromone attractive to male moths of the family Noctuidae. Vibration sensitive hairs on the spider’s outstretched legs can sense the wing beats of an approaching moth. The spider begins to swing the bolas around in a circle beneath the moth until it is hit by the sticky bolas. It flutters in tethered flight while the spider hauls it in. The moth is then bitten, wrapped and either eaten or hung. Several moths may be caught in a night.”
Thats so great, thank you. Its an impressive (or magnificent!) looking creature! I look forward to getting out there at night and seeing if we can sight it! Will send you an update photo if we manage to catch it in action
There has been a change to the centre egg since I emailed, its sac surroundings have coloured in patches of rusty orange. So perhaps hatching will begin shortly!
Keep up the great work, thanks again!