Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Suborder: Araneomorphae
Family: Araneidae
Genus: Celaenia
Species: Celaenia olivacea
Common name: Bird-dropping spider
Though the small (7mm) Celaenia olivacea is a native orb spider it is unusual because it builds no orb web. Their common name is the "Bird-dropping spider" because of its strange shape and strange colouring which makes it look like birds droppings (see photos below). This is a specialised camouflage against predators. They are found usually dangling upside down on a silk thread. It was not known how these spiders caught prey with one thread. It seems that they are able to attract male leafroller moths by producing a special scent like the pheromone produced by a female leafroller moth to attract a male partner. The female Celaenia lays up to eight small round silk egg sacs which are 5 to 6 mm wide and have a stalk on one end and have four or five knobs on its surface. These are found hanging in a group tied together with silk threads. The female spider hangs on a thread underneath the eggs until they hatch.
The hanging egg sacs of Celaenia olivacea
