Although other PhD students had suggested otherwise, I reckon that the thesis proposal seminar can’t be more gruelling than running the social gauntlet called ‘December’. Christmas function after Christmas function after family get-together after beach road trip. It’s like we honestly believe that civilisation as we know it might end on December 31st and we literally have x number of days to see each other before we are all transformed into giant tiger prawns by the rising 2014 sun.
Now I accept that my PhD thesis topic is so blue-sky that you should be able to see out of the stratosphere. So when family/friends/acquaintances/my own doubts ask me ‘so what is your research going to contribute to society?’, my face does not look the way it does because I have, for the first time, been forced to confront the uselessness of my own field of study. At most, I’m just running through the list of comebacks I formulated from the last time that I was asked that question: five minutes prior1.
But before the university closed on the 20th, a few of us managed to get into the field near Waitomo for a bit of late night harvestmen and sheet-webs spider voyeurism.
The activities for the period included:
- manual searching, the technical term for [from here on ‘tttf’] my holding containers are arms-length and trying to close them over giant spiders;
- pitfall trapping, tttf digging holes for plastic containers so that the top is flush with the ground with a lid elevated slightly above the ground so that insects/arthropods fall in overnight and can’t get out again;
- observations ranging from between 1.5 to 2 hours in length, tttf sitting in the dark with a red light and watching spiders do nothing.
The idea was that pitfall traps would help me to catch males which will wander around to find females in their webs. We were a little short on time so on the first day I identified a few sheet-webs and put the pitfall traps near the tree trunk. Asides from a few tiny beetles these didn’t fetch much which isn’t really that unexpected given that the containers were only out for two nights, I had no idea initially whether the webs actually even had spiders (although most of them did when I checked during the night), and males are apparently less active during December (of all months).
Manual searching (read: moderately frightened flailing) was a little more successful. The last time I’d been to Waitomo I’d collected the wrong species (Stiphidion facetum, not Cambridgea spp. duh.) but this time I think I actually found some Cambridgea spp. which is different from the species that I collected in the Waitakere’s which are now living under my house and are laying eggs yay.
What was also interesting was that I found several bodies sans abdomen in the webs of a large-ish female (?). It looks like a couple males and a couple females of the same species. Maybe I’m being an idiot (always possible) but they don’t look like moults so while I don’t want to come to any conclusions until I’ve seen it happening, I wonder whether the ratbags are cannibalising each other. Common (un)knowledge(?) says that spiders do not ingest their prey whole sale which raises the question of how they would be ingesting the bloody abdomen but it may be that the chelicerae play some role in mushing (technical term) up the prey for external digestion.
I might have a better idea after the break as I have a large male in the freezer along with his weta prey. I’d caught him after an observation nomming on the weta in his web so it will be interesting to see how much of the weta is left in the container.
Another interesting thing I saw during that particular observation is that there is a certain species of smaller spider which might be parasitizing the sheet-web spider’s kill. I caught a couple of them in a container. They would be maybe a 20th of the size of the sheet-web spider and would very very carefully approach the prey item, perch on a point that wasn’t too close to the larger spider and… … I assume it was eating. Red light. More like lame light.
There are a couple different species which seem to hang out on the edges of these webs and I think it would be interesting to identify these guys – could possibly just do an observation on a web and try to collect the whole structure and all its occupants. As I said, I already collected two of one species by which I mean I now I have one because I kept them in one container and the larger ate the lesser. #Studyingcarnivores.
The university is closed at the moment so I’m looking forward to doing some keying up and getting a handle on how to measure chelicerae size and genital morphology. I’ll have to go back at some stage to do more observations and pitfall trapping but at the very least I think I have several specimens from several different species which will be helpful for constructing a molecular phylogeny.
Also caves are cool and we got to knock harvestmen off the ceiling with broken stalactites.
1 One I would like the chance to use is ‘it’s not about what the study of spider genitals contributes to society. It’s about how long the study of spider genitals can keep deviants like me locked away in a basement laboratory’