Spiders that eat other spiders aren't rare. In Aotearoa/New Zealand, whitetailed spiders (Lampona spp.) are probably the best known, but the common daddy longlegs spiders (Pholcus phalangioides) like this one will kill anything trapped in their webs, including other spiders. I mentioned this in the caption to an earlier photo, but at that time didn't have a photo to document the claim. Well, here's one. I noticed this today and immediately reached for the camera. The prey spider was bundled up tightly in silk and rubbish, so I couldn't identify it (and I wasn't prepared to steal it), but it might have been a cobweb spider (Cryptachaea veruculata).
Wow.This is the kind of zoom I yearn for.
ReplyDeleteImpressive shot. Who knew they were hairy? :)
ReplyDeletePurestGreen, it's an amazing world when you can get up close to it.
ReplyDeleteAndrew, some of those hairs are remarkably complex, too.
I'm surprised. If that is a wolf spider then, since they don't make webs, I can understand why the daddy long legs was able to capture it, but if it is a funnel web spider or any of the spiders that make such webs, it seems strange that another spider's webs would have caught it. I've seen a lot of jumping spiders, crab spiders, huntsmen, and wolf spiders catch other spiders, but rarely a web-making spider. That prey spider must have been in shock when it all happened, like, "Whuh? Where am I? Who's there? OMG!"
ReplyDeleteMiguel, I'm not sure of the identity of the prey spider, so it might indeed be one of the wandering sorts. However, even if it is a web-builder, they do move around from time to time, either deliberately or accidentally. But yes — I wonder what went through its head (other than a set of fangs)?
ReplyDeleteThe moving around bit, yes, I've seen that, too. But don't web making spiders have some sort of oil or anti-sticky agent on their feet or on their bodies that makes it difficult for them to get caught in their own webs? That's what I was vaguely referring to.
ReplyDeleteSpiders are fascinating. They seem to have evolved purely on their own terms. And so much of their existence seems like fun: take for instance the spiderlings that soar amidst the clouds on spider silk, sometimes for years!
Miguel, it seems Pholcus phalangioides not only ensnares other spiders in its own web, but also invades the webs of other spiders to capture them, so it has potentially a wide range of prey species. However, in this case I suspect the prey spider wandered into the daddy longlegs spider's web, as the event I photographed took place about a metre below the position where the daddy longlegs has set up its home.
ReplyDeleteOn somewhat closer inspection of the now rather dry, shrivelled and well-wrapped corpse, I think my guess about the prey species being a cobweb spider was wrong. I don't know what it is (was).
To the best of my knowledge, spiders generally avoid being trapped in webs by walking only on the non-sticky threads (only some have added droplets of glue). I don't know about the oils — perhaps it's true, but it's not infallible. The daddy longlegs spider sometimes gets caught in webs it's invading; when that happens it bites off the threads and replaces them with its own. You can read about it in the 1987 paper by Robert Jackson and Roxanne Brassington (Journal of Zoology 211(2), pp. 227-238).
And oh yes, spiders are amazing. I'm still astonished by the simple fact that, as far as anyone knows, ALL spiders (and that's a huge number of species) are predators. There are no vegetarian spiders and none eat anything other than prey they've killed themselves. Yet nothing I can think of in their anatomy, physiology and behaviour seems an insurmountable obstacle to plant feeding?
Weird. I work with Roxanne every day and didn't know she was wrote that... I will, of course, send her a link to your blog entry. :)
ReplyDeleteIt's a small world, Andrew. Well, at least New Zealand is. Say hi for me — she might remember me.
ReplyDelete> Say hi for me — she might remember me.
ReplyDeleteI did and she does. :)