Intertidal Spiders

Inter-tidal Spiders – A feature article from Steve Pearson.

The Whitsunday Shire contains a large diversity of terrestrial habitats. Just consider the different changes in vegetation types between the Islands around the Reef and out at Collinsville. This diversity is reflected in our wildlife even for instance in the great local diversity of spiders. Whitsunday Shire has more than 300 different species of spiders.

Just for a start there are 3 amazing types of spiders that live in the inter-tidal zone and create shelters/homes that go under water at high tide, then come out and hunt while the tide is out. As the tide comes back in the Maratus species a Salticidae jumping spider just finds a hole where ever it has roamed and builds a new web for a home.

The coral spider Desis species, Desidae family, has a permanent home in coral and when the tide is out the spider comes out to hunt near its more permanent home. They then just go back inside and re-web the entrance over.

Yet another approach is used by the intertidal trapdoor spider Idioctis yerlata of the Barychelidae family. This species has a trapdoor web in the coral and opens the door and hunts close by while the tide is out. When the tide is coming in it goes into its hole, pulls its door shut and stays inside in the air pocket,while the tide goes over it.

Just beyond the tidal reach there are spiders living in flotsam and debris, some species live in suspended webs on the shoreline and some in the adjacent forest in ground leaf litter, some live in tunnels in the ground, others in tunnels into rotten logs and stumps. Still other species of the forests live under rocks, some on tree trunks, some in rolled leaves and some are just roaming around the open forest floor or on tree trunks at night out in the drier forests near Collinsville.

To all these residents we can add the spiders that are wind-blown wanderers travelling the world on their threads of gossamer to drop in to the Whitsundays every few years and then eventually move on again. No wonder that spiders are an integral and ever-present part of our amazing terrestrial ecosystems.

Steve Pearson is a local dedicated nature photographer. Steve is a retired QP&WS ranger who spent a large part of his career at Eungella and in the Whitsundays. Assisted by his wife Alison, Steve has accumulated a comprehensive photographic reference of plants and also the less understood and under-appreciated elements of our region’s ecology such as invertebrates and fungi. To view more of his photos go to – steve and alison1@flickr