Bird Dropping Spider: The Unique Mimicry

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Arachnophobia? Let’s take a look at the bird dropping spider aka “death’s head spider” first. This arachnid is one of the spider groups that evolved to survive in nature. Coming across one of these could be a nightmare but fear not my trembling child, they are not dangerous. They do bite if provoked though, so don’t touch them. Want to find out more about the bird dropping spiders? Check out the details below.

1Appearance

image: epitree

Male bird dropping spiders are smaller than females, measuring only 2.5 millimeters while females grow up to 2 centimeters long. The most distinctive feature of these spiders is the large and broad triangular abdomen that they have. This abdomen has splotches of white and brown or pale white, black, and gray that look very much like a bird dropping. Some of the markings also make them look like a skull; hence, the name Death’s Head Spider. The moment they tuck their legs up against themselves, you can no longer differentiate between a dung or a spider.

Despite being large, a bird dropping spider can actually sit huddled on a branch or leaf out in the open without being noticed. Simply because its coloration and posture resemble a blob of dung more than an actual spider. This mimicry is to avoid predators, mainly birds, and even us humans cannot notice them.

2Behavior

When it comes to interesting facts about the behavior, their breeding habits are probably the most fascinating. First of all, these spiders have huge egg sacs that are marble-brown in color. Each egg sac is around 12 millimeters, and it contains over 200 eggs. A female bird dropping spider can produce up to 13 sacs that she silks together in a group. The more I look at those egg sacs, the more they look like chocolate balls. Maybe I am just hungry. Both males and females stay motionless on their web during the day, and they hunt at night.

Are bird dropping spiders aggressive or dangerous? They are not, you can just use a cold pack to apply on the site if you are bitten. Though the toxicity is unknown, the worse their venom can do is cause mild pain, minor swelling, or redness. This is to reduce the pain or swelling that you experience, apart from that, everything is all good.

3Feeding & Habitats

image: Anura

One of the most interesting things about the bird dropping spiders is the way that they feed. A bird dropping spider uses mimicry to capture its only food, which is male moths. When the night comes, it hangs from the edge of a leaf or twig using its short silk thread. It outstretches its forelegs and releases a pheromone that mimics the airborne sex pheromone that female moths release to attract males. When the unfortunate male moths approach close enough, the spider will use its strong front legs to capture the prey.

Many of you probably expected, bird dropping spiders are found throughout eastern and southern parts of Australia, and New Zealand. Some of them also make their way to Uluru which is in Central Australia as well. At the same time, they are also common in suburban gardens though people don’t really notice them.

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