Fun with Spiders

This September I was lucky enough to go to Hamburg for a couple of weeks to run some predation experiments with spiders. The experiments were part of a collaboration with Prof. Susanne Dobler and Prof. Jutta Schneider to test the effects of the wood tiger moth’s defence fluids on model spider predators (in this case Nephila senegalensis and Larinioides sclopetarius). Stay tuned for the results!

 

 

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Spiders in space

While hard at work (obviously) I recently came across this awesome picture on buzz hoot roar.

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Buzz Hoot Roar – a “graphics-driven blog that shares and/or explains a scientific concept in 300 words or less.” Check them out!

This is awesome for two reasons: 1. I had a pet jird when I was a kid called Nefertiti, it’s a good name. and 2. SPIDERS IN SPACE!

But seriously, the fact that Nefertiti (Phidippus johnsoni) was able to not only adjust to hunting in zero gravity, but then back to gravity upon her return to earth is a testament to the amazing behavioural flexibility of jumping spiders.

I’ve written before about my love of jumping spiders, and posted far too many photos of my own but now I want to focus in on their impressive cognitive abilities. In my spare time I’ve been reading though Marie Herberstein’s book “Spider Behaviour: flexibility and versatility”. As the name would suggest this is just full of examples of cool spiders doing cool things but I’m just going to mention a few that relate to Nefertiti.

Firstly, hunting in zero gravity isn’t the only skill these little guys can pick up. Phidippus princeps can learn to associate colours, such as red or blue, with food and use these colours to locate prey in a maze. Not only can they learn rules like this, but they can take the context in which they learnt a particular rule into account. One really neat example (at least for me) involves feeding them seed bugs, in this case Oncopeltus fasciatus. Like most seed bugs O. fasciatus sequester chemicals from their natural food (in this case milkweed seeds) which make them taste bad to predators. If however, you feed them on sunflower seeds, as I and most lab researchers do, they have no nasty chemicals to sequester and taste just fine. (Note, by taste fine I mean to predators like birds and mantids, I refuse to eat one regardless of what it’s been fed.) A study by Christa Skow and Elizabeth Jakob found that the spiders quickly learnt to avoid the bugs if they were fed ones that had been raised on milkweed seeds, but if the spiders were given bugs that had been raised on sunflower they kept on eating them quite happily. So far so good, but what they did next was to train the spiders in two different environments. When spiders that had learnt to avoid the bugs in one environment were presented with them in a different environment they attacked the bugs at a higher rate. Not only is this a cool example of context-dependent learning, it also makes sense as a forging strategy. Given that the bugs take their chemical defense from their food, they may have varying levels of chemical defense in different areas based on the types of plants available for them to feed on. That means that the likelihood that a bug is poisonous may be different in different habitats. So even if you know to avoid the bugs near the bushes, it might still be worth having a taste of this one you found by the river, just to be sure.

Given the intelligence of these little creatures, it is unsurprising that environmental enrichment has also been found to affect their behavior. Lab reared P. audax performed worse than wild-caught spiders in a variety of behavioural tests, (including my favorite, will they attack a video of an insect on a touchscreen?). However, their performance was improved if they had been kept in a larger cage and provided with a green stick. I’m glad to say I took this study to heart and all my spiders had at least two sticks in their cages. By the looks of this video Nefertiti’s cage also had no shortage of things to explore and keep her brain sharp during her retirement.

 References:

http://newsdesk.si.edu/releases/world-s-first-spidernaut-lands-smithsonian

Herberstein, Marie Elisabeth, ed. Spider behaviour: flexibility and versatility. Cambridge University Press, 2011.

Christa D. Skow and Elizabeth M. Jakob, Jumping spiders attend to context during learned avoidance of aposematic prey Behavioral Ecology (January/February 2006) 17 (1): 3440 first published online October 12, 2005 doi:10.1093/beheco/ari094

 

Yet more spiders

The last few weekends I’ve been helping out at an outreach event at the Bell Pettigrew Museum. The event, Gardenlife: biodiversity in urban gardens, is part of the British Ecological Society’s Centenary Festival of Ecology and is designed to get children interested in the awesome little creatures you can find in your garden. It means I get paid to run around with sweep nets and pooters catching insects and spiders to bring back to the museum for identification.

One of the coolest finds so far has been a rather unfortunate cucumber spider.

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As you can see the little guy has been parasitised by a wasp (probably a Pimplinae of some sort but don’t quote me on that). The spider is still very much alive as the larva will eat around its vital organs in order to avoid killing it for as long as possible. My plan is to keep the spider until the wasp pupates as I’ll have a better chance of identifying it then.

Overall it’s been an unlucky week for spiders as my male Plexippus petersi Baby died two days ago. While sad, this has given me an opportunity to get some shots of him under the microscope (a previously impossible task).  One of his close-ups is below and I’ve added the rest to the gallery.

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Jumping spiders

My obsession with jumping spiders (or Salticidae as they are properly known) started during my undergraduate honours project when I spent several months carefully photographing (sadly deceased) specimens from twenty nine species in order to study their body shapes. (For some idea of the amazing variation in body shapes amongst the  Salticidae check out this video by Dr. Wayne Maddison, and then check out everything else he’s ever done, it’s totally worth it.) As most jumping spiders are small (the largest just push 2cm in length) it’s not until you get them under a microscope you realise quite how beautiful they are.  Many of the species in my study were covered in flecks of gold and silver.  They also have giant forward-facing eyes which have made them hugely popular with wildlife photographers (as a quick Google image search will reveal).

One of the photos from my undergrad project.  This particular spider is Heliophanus patagiatus
One of the photos from my undergrad project. This particular spider is Heliophanus patagiatus

My enthusiasm for jumping spiders only grew as I became more interested in sexual behaviour.  As the now-famous video of peacock spiders shows, male jumping spiders often perform complex courtship displays.  One of my long-term career goals is to study sexual conflict in these spiders and how that may have shaped these elaborate behaviours; I recently decided that a good first step on my way to this would be to actually keep and breed one of the commercially available species.  Thus two weeks ago I became the proud owner of a breeding trio of Plexippus petersi courtesy of Exopet (who also supplied some of our mantids).  I named them after cultivars of kiwi fruit (don’t ask why) so the girls are rather appropriately named Fuzzy and Golden and the male is Baby.  All three are happily settled in and feeding well of the endless supply of drosophila from the genetics labs.  I’ve even see Baby displaying to the females (I’m hoping to get a decent video up next week).

In the meantime here are some of the best photos of Baby I’ve managed to get.

Check out those pedipalps
Check out those pedipalps

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Look at his little face
Look at his little face

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