10 Nov, 2008

The arachnid uses an anchor thread to return to a resting place in the middle of its web.

Today I returned to Thailand's Tham Pha Tha Phon non-hunting area on the western side of Thung Salaeng Luang National Park to explore around the base of the cliffs and outside the caves.

I was hoping to find one of the many snake species that inhabit this area, but instead settled on filming a spider (Arachnida sp.) that had a very interesting technique for navigating around its web.

When I first saw this spider it was busy collecting small flies that had become entangled in its web.

In fact at first I was so amazed at how many flies the spider was catching that I felt sure every time it caught one that it would be the last for a while, but then another one flew into the web and was duly bundled up.

I ran back to my car for my camera gear and quickly set up. The supply of flies did in fact slow down somewhat, but there was enough action for me to get some film and to see the way this spider used an anchor thread to continually bring it back to its resting place in the middle of the web.

If it went downwards from the central part of the web, it returned by jumping off the web and swinging back towards the middle whilst hauling itself up its anchor line.

Of course if it ran upwards to catch a fly, the return journey actually involved leaping off the web and falling down past the central point and then hauling itself back up. This all happened very quickly. In seconds it had collected its prey, brought it back to the centre of the web and stored it and was back in position.

On several occasions the spider took exception to bits of plant material that got stuck in the web and attempted to cut them out, with varying degrees of success.

The back of this spider had a pattern of brown and yellow blotches, but on the underside was a line of electric green.

As with the small subjects I filmed yesterday, I have tried hard to throw the background out of focus as much as possible in order to isolate the spider in the image, and at times this gave a very pleasing effect as the background greens and browns blended into one another.

The last few days have been dry and the temperature has dropped markedly at night, with a distinct chill in the air, so it would seem that the long wet season may be over at last and our 'winter' is on its way – four dry months with somewhat lower temperatures than normal, but not really a true winter.

– by Darryl Sweetland, Earth-Touch crew © Earth-Touch

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