Wednesday, March 7, 2012

An Arachnid Winterland: Australia's wolf spiders escape flood waters

The picture above, taken by Daniel Munoz for Reuters, depicts a tranquil winter farmland scene - a blanket of white snow gently covering the ground. Ah, a classic winter tableau.

Or is it?

If it's winter, why is there no snow on the hillside behind the trees? And if you could get closer, you would see that it's not snow at all.

It's spider webs.

In Australia, following heavy rains and flooding in New South Wales, thousands of residents had to move to find drier ground. In the city of Wagga Wagga, over 8,000 residents needed to evacuate. Someone, or something, else also needed to evacuate: thousands upon thousands of wolf spiders.

Wolf spiders reside in tunnels or burrows in the ground. They line their homes with a silky web that facilitates easy and quick movements within the tunnel. With the flooding, the spiders moved to higher ground and as the soil remains saturated, returning to a damp home was out of the question. So the spiders built their webs above ground - their new homes spread out across the Australian farmland, looking for all the world like a fresh layer of snow. That is until you get up close and see all the wolf spiders wandering about over the webs, patiently waiting for the ground to dry out so they can return to their normally solitary, hidden lifestyle.


The many webs actually represent failed attempts at "ballooning." Ballooning is where a small spider releases a long silky strand of web which catches the wind and suddenly the spider is airborne. An effective means of travel - or, in this case, escape from a threatening situation - for small lightweight spiders, but many of the spiders here in Wagga Wagga were too heavy and so the threads would accumulate. The sticky threads would also latch onto the extra moisture in the air, making the webs more visible

However, while they wait for better living conditions, the spiders also perform an important service. The residual floodwater became a massive breeding ground for mosquitoes and other insects. As wolf spiders feed primarily on insects, that meant there was food aplenty.

"The amount of mosquitoes around would be incredible because of all this water," said Taronga Zoo spider keeper Brett Finlayson told the Sydney Morning Herald. "The spiders don't pose any harm at all. They are doing us a favor. They are actually helping us out."

As the soil begins to return to normal, some spiders will return to living underground, some may move on, while others will unfortunately become prey to birds and other small predators. It is expected that by the warm, dry days of summer, the population will have returned to normal.

I don't mind spiders. In fact, I'll leave the magazine or newspaper unrolled and will give them plenty of leeway since I know they help keep other insect populations in check.

But I'm still itching a bit just thinking about Australia's homeless arachnids.

Source: Sydney Morning Herald

1 comment:

Wolf spider said...

Just awesome nature, what an wonderful scene!