Deception in Daintree Rainforest – Spiders
Knowing the rainforest so that we can present its values to visitors from around the world has become our infinite vocation. Secretive, obscure, cryptic, camouflaged, mimicking are terms that describe strategies of rainforest deception that are employed by many of our critters to avoid detection. The enrichment of our interpretation has evolved from just being here to a capacity to see life forms that are hidden from the casual observer.
Every discovery alters our mindset and opens the door to more discoveries and connections and gradually our understanding of life in Daintree Rainforest expands and deepens. The inventiveness of nature knows no boundaries, yet our perceptions are clouded and constrained by past experiences.
Spiders are particularly inventive. According to Wikipedia, in 2008 an estimated 43,678 species had been recorded. http://en.wikipedia.org/wiki/Spider
A simple bird-dropping on a leaf moves and we have found the bird-dropping spider. Camouflage and mimicry deceive the eye, while other techniques attract specific prey. A bird-dropping spider – Phrynarachne decipiens avoids predation simply by looking like bird excreta, but it also emits a biochemical signal that attracts specific moths that live off bird droppings. What a disappointment to have a tasty morsel turn into a predating spider that wraps you in silk, and injects digestive juices into you to make the tasty morsel!
Camouflage and mimicry together prove successful with the Poltys spiders. These are orb-weaving spiders that can be seen at night in their perfectly woven wheel webs. When daylight comes they and their webs disappear, to re-emerge at night in the same place. After much searching for Poltys species we discover Poltys nobeli and Poltys laciniosus in their daytime positions as a twigs, hence the other name “twig spiders”. The larger Poltys illepidus is known as the “Tree Stump Spider.” Their colour blends in perfectly with the their territorial tree and they fashion the position of their bodies to mimic a twig, or a small stump.
Lichen spiders became one of our early intrigues. A patch of lichen on a tree shifts a little, enough to catch the eye and we have found a Lichen Spider – Pandercetes gracilis, blending superbly with surface characteristics of their tree. These spiders flatten their bodies into the lichen on the tree to remain strategically hidden from predatory birds and simultaneously well-positioned to ambush unsuspecting insects. Poorly disguised individuals are readily picked-off and the gene pool is progressively refined.
Given the prolific numbers of spiders and katydids in the rainforest, and their extraordinary capabilities for avoiding detection, it is impossible for us to provide full coverage of the Daintree Rainforest. We do know that there is a lot more than meets the eye!