Christmas is just around the corner and for many this means that it is time to head to the sea. Beach holidays have long been a tradition for kiwi summers. I was no different while growing up and through my adult life. We spent a lot of time at the little beach village of Kaka Point, at the far northern end of the Catlins, in South Otago.
Not a lot deterred us from hitting the waves. The weather could be a little iffy and the water a little cool but that didn’t matter. You might have a to share the surf with a few other hardy swimmers and the occasional seal but it was bliss. But now I find that I may have been sharing my waves with something slightly more sinister!
One thing that we know about spiders is that they don’t love water. However, it turns out that there are spiders who do spend time in the sea. This is not just in the inter-tidal zone where we might see them dodging between waves. Marlene Leggett, Cor Vink and Ximena Nelson have a new paper coming out that looks at marine-associated spiders and their adaptations for survival.
Spiders!
Marlene terrorises us by showing that these spiders are all over the world. No beach is safe! She does reassure us that these water arachnids only make up 0.3% of all spiders (although that still seems too many). She reviews the work that has been done to show how spiders, usually very terrestrial, can survive in such a damp environment.
Some have hairs that trap air bubbles around themselves, other can use webs to close off empty shells to keep the air in. Some can go into a coma where they reduce the amount of oxygen required. Inter-tidal species can run away from incoming tides. These traits allow spiders to exploit a habitat that would otherwise be forbidden for them.
It’s all very fascinating. Spiders have had to change the way they eat, avoid predators, reproduce, move, accommodate extreme temperatures, and cope with water pressure. Marlene summarises the adaptations. It’s a great read.
However, spiders in the sea is not really what you want to think about when you are rushing into the waves, boggie-board in hand. It’s almost a Gollum moment (as the Nazgul fly over him he shouts in horror “Wraiths! Wraiths on wings!”)
“Spiders! Spiders under water!”
Have a great Christmas holiday at the beach!
Adrian Paterson is a lecturer in Pest-Management and Conservation at Lincoln University. He generally likes spiders, but only when he can see them!
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