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

 

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Mantids!

Following our work on the sexual cannibalism literature last year we are now branching out into actually studying a sexually cannibalistic animal.  In this case preying mantids!  As always when embarking on the study of an exiting new species, our first step was to work out how to keep them in the lab.  Thankfully preying mantids are popular pets and husbandry information is easily available for many species.  We’ve decide upon Sphodromantis viridis or the African Giant Mantid as our study species (a decision that may or may not come back to haunt us as we grapple with their large size and long life-span).  One benefit of this species is it is commonly advertised as a ‘beginner species’ and that I have actually kept them in the past.

So back in February I tracked down my old supplier and bought three 3-4th instar nymphs just to check that my planned set-up would work.  The three were a big hit and quickly took to their new homes (converted innocent veg pots) and new diet (spare Nasonia and Drosophila).  We named them Voracious, Rapacious and Suicide; names that may seem familiar to those of you who read our last paper!

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In the months since they arrived all three have shed and grown considerably.  They are now joined by 5 other nymphs, from a variety of sources, who should (with a bit of luck and a decent sex ratio) form the basis of our breeding colony.  So far we’ve had only on death and I suspect that was from the stress of being posted during the glorious snow of Scottish “spring”.  Hopefully all our mantids will continue to grow so I can spam this site with photos of them instead of actually writing blog posts.

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