Monday, 3 February 2014

Essence of spider

I'm meeting with my supervisory team this Friday to discuss my methods, now that the proposal is almost done. While waiting for proposal corrections and stuff, I have been doing a few things that will hopefully mean I can hit the ground running when I get official permission from the university.

As I have slowly been facing the ugly truth that Cantuaria taxonomy is far from straightforward, I have been compiling pictures of the abdomens and genitalia so that I can quickly narrow any specimen down to a near match. This should speed up identifying each one that I collect. The definitive works on identifying New Zealand spiders are the "Spiders of New Zealand" books by Ray Forster and others. The second book in this series (Forster and Wilton, 1968) describes all known species of Cantuaria. I have been using it to identify the spiders I currently have in the freezer, focusing particularly on the genitalia but also claws and abdomen patterning, as the authors seem to consider those characters most useful to distinguishing species.

Claws on the end of a Cantuaria leg - note that there are 3 claws, and the bigger two ("superior" claws) have a big tooth near their base. Those are the kind of characters one looks for when trying to find what species a spider is.

However, my advisor and I have discovered that claws are pretty meaningless, varying in their notch patterns between individuals, and I emailed another spider guru who told me that he usually goes by male genitalia, and if he finds a female in the same place that looks similar then they are probably the same species. Most of the characters in the literature are next to useless. So....cock.

By the way, in case you are wondering what spider genitalia looks like, feast your eyes on these beauties...

The female's internal genitalia at the top, the male's palp at the bottom. Pretty cool structures, huh?

In addition to that, designing my proposal seminar, reading stuff, applying for permits (looooong laborious process) and "collecting" more Cantuaria (more like looking for them and not finding any - good job New Zealand is scenic), I started extracting some DNA from my specimens. DNA extraction sounds cool and is full of words like "Qiagen", "elution" and "lysis" but it really is just a case of making spider soup and then washing it through a sieve to get the muck out. You dissect the muscle out of a spider leg (easy in my spiders, I pity people working on the smaller species), add some protein-cracking enzyme to it and cook it overnight. What you have in the morning is free DNA floating about with a bunch of other stuff you don't want. You then wash the spider soup through a filter using a bunch of different buffers, but you get to use the centrifuge which is cool because it always sounds like it's going to take off. Then what you have is spider DNA suspended in a solution. Essence of spider. If you can follow a recipe, use a centrifuge and a pipette, you can extract DNA. My favourite bit is the dissection but my second favourite bit is all the labelling and categorising of the samples. Organisation is important in doing molecular work so I am in my element.

I just moved house and I'm helping my friend move house, and I am also house sitting, so I have many houses at the moment and am pretty knackered. I'm going to pick one of them to sleep in and say goodnight. Goodnight!

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