The Bird-dung spider, also known as the Bird-dropping , Orchard spider or Death's Head, belongs to the Family Araneidae. This spider is guaranteed to be ignored by just about everybody in the animal kingdom , except maybe a dung beetle!. There are believed to be at least four different species of this spider in Australia.
The main characteristic of the Bird-dung spider is that it looks like bird faeces (droppings) which is pretty gross. The spider has a leathery looking lumpy abdomen which is brown, cream and white in colour and looks much like pigeon poop. However this unattractive appearance acts as a unique camouflage and is extremely effective in keeping itelf safe against predators such as birds , wasps and I guess humans ! Another unique characteristic of this spider is the scent which it releases to attract male moths to its web. The scent, known as pheromone, is released from its abdominal glands .This chemical scent mimics the sex pheromone which is released by female moths to attract the male moth. Once the male moth gets a whiff of the scent, it will fly towards the smell expecting to find a female moth. Imagine the moth's surprise when the motionless bit of bird dropping comes alive ! The spider will use it's front legs to grab the moth and then it will devour it on the spot. The average size of Bird-dung spiders are 12mm for females and a relatively smaller 3mm for males. The female spider lays her eggs (over 200) on a silken sheet and then using a different type of silk,wraps it up into a large ball. The ball is then coated with a special body fluid which hardens and waterproofs the silk, thus protecting the eggs. The ball is marbled brown in colour. A Bird-dung spider may produce many of these balls and hang them from fine threads among the shrubbery. The female spider is often found near, on or under her eggs, keeping guard.
The spider is found throughout eastern and southern Australia, usually in orchards or where their favourite moths are in abundance. The spider can often be found sitting on the leaves of fruit trees totally overlooked, due to its appearance (any wonder). The spider hunts at night but during the day it can be found sitting well exposed on a leaf or branch, safe in the knowledge that no one will bother it, because it looks like poop. The spider will then release a scent known as pheromone from its abdominal glands which attracts male moths.The young Bird-dung spiders, which have yet to produce moth attracting pheromone, build small wheel-webs to catch tiny prey until they mature. The easiest way to spot one of these spiders is to look for the marble coloured egg sacs.
Food and Predators
The main food source for this spider is the Noctuid moths, which are nocturnal . These moths, and in particular the male moths, are the spiders main source of food. The spider keeps its legs folded against its body during the day but at night the spider hangs down from a leaf or branch (by a silk thread) and holds its forelegs (front) outstretched waiting for its prey. As mentioned above, the spider releases a scent which attracts the moth to the trap. Some species hunt during the day. Lying in wait, the spider ambushes any unsuspecting insect which comes within range. It will jump on it's victim and grab it by it's spiny front legs with super fast speed . One of it's major predators is the wasp, who just loves stealing their eggs.
Friend or Foe ?
Even if you think you have spotted a Bird-dung Spider, don't expect it to give up it's act straight away. These spiders are great actors and hate being caught out as an impostor. So even if you poke it , it may still pretend to be a bird dropping and not move (or it may actually be bird dropping). If you persist and it is a spider, it will move slowly away, but please don't harrass the poor creature. Isn't it bad enough it looks like ....(well you know what I mean!). The bite from a Bird-dung spider is not considered harmful.