Yes, thats right, this entire post has nothing to do with the Pacific Crest Trail. Just wanted to record my thoughts on some other things... This entry is really more of a personal journal thing than a trip report, so feel free to skip this if youre reading about our trip. I didn't carry a journal with me, too heavy.
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I've been thinking about bats a lot on the hike. Originally, I was going to use this trip to figure out whether or not I wanted to do a PhD. Well, I've decided before I've even started. I can't stop thinking about all the things I want to learn about and the experiments I want to do.
For my M.Sc., I studied the social calls of a vampire bat, the white-winged vampire. I've only managed to publish one paper from that work since I graduated in December: I showed that the social calls form antiphonal duets and allow the bats to vocally discriminate individuals. So after I finish this lovely hike, I've got 2 or 3 more papers to write up and submit in 2008 before I start a PhD.
White-winged vampires. Photo by Dan Riskin
First, I have to do a multivariate analysis of the call structure to ask the question: "What features of my bat's call "encode" information on individual identity?" That will be a good way to get better with multivariate stats.
Second, I have to analyze the data I collected this last fall. I wanted to know if my white-winged vampire bats use their social calls to keep track of each others' locations. I did a simple experiment where I recorded the amount of antiphonal calling during two conditions. In the test condition, I scrambled the locations of the bats in a dark room (There's no light in the room, the walls were lined with anechoic foam, and the bats were in nylon mesh cages.) Then I recorded the amount of vocal exchanges. In the control condition, I pretended to move the bats around, but put them back in their original position (a fake scramble). I randomly repeated these trials with different individual bats. My prediction is that the bats called more often when they hear that their roostmates are in different locations. I think the bats use these calls to localize certain individuals. But like I said, I havent analysed the data yet, so I'm not sure they support my hypothesis. Finally, I will try to use the rest of my Masters data in a descriptive paper on the vocal repertoire and social behaviour.
In 2009, I'm starting my PhD, probably with John Ratcliffe at Memorial University in Newfoundland. Yeah, I know, I've never heard of Memorial University either. It's not exactly Berkeley or Cornell. And yes Newfoundland consists of some barely populated islands just south of Greenland. BUT... I'm pretty excited to work with Ratcliffe. He does really good work (example, read discussion) on bats and behaviour and does exactly the kinds of experiments I like and want to get better at. (And frankly, the guy doesn't screw around when it comes to publishing lots of good papers. He's authored 22 papers since he finished his Masters in 2001. Just for 2008, he already has his name on 9 papers, including one in Nature. See, that's the way I want to operate. Learn from the masters, I say. Also, he has mucho funding. Besides, Newfoundland even has some climbing, not that I consider such things for where I do a PhD....)
Anyways...
A bunch of research topics have been floating around in my head. I'm sure most of them are stupid, but I want to get record them somewhere anyways. Some ideas have to do with reciprocity. Vampire bats perform reciprocal altruism via food sharing. (Heres some footage I took.) Jerry Wilkinson showed that the bats' sharing of blood (via regurgitation) fulfills all of the conditions for reciprocity outlined by Trivers, except for one I think: He didnt show that bats punish "cheaters". Imagine a bat that tries to get blood from partners but doesnt reciprocate. The idea is that donor bats will withold giving blood to begging bats unless they have received blood from them in the past. But this anti-cheating behaviour hasn't been observed yet. How long will a bat give blood to a sharing partner before she says "Ok. Enough is enough. When was the last time you fed me, eh??" It would be interesting to examine how bats react to a conspecific who doesn't reciprocate...
Last time I was in New Mexico where we have captive white-winged vampires, I tried to observe and manipulate food sharing. I found I could observe it fairly easily with an infrared camera and could get one bat to elicit it from others by keeping it hungry for one night. So there's some potential for interesting experiments there.
Which is more important: sharing food with relatives or sharing food with bats that shared food with you? If she had to choose, would a vampire bat favour estranged kin or a long-term "friend" (whose shared blood with her in the past over a long period of time)? Would be interesting to see whether kin selection or reciprocity plays a larger role...
Another set of ideas I had related to vocal communication. For my masters, I suggested that white-winged vampire social calls could be considered "contact calls". That is, they convey individual identity and location. But- What's the adaptive function of contact calling in these bats? Do they monopolize and defend a group of bird prey? Do they travel in groups? If so, why? Are the calls used as an "entrance pass" to share prey with certain individuals? Why do some vampire species use these calls while others do not? I could work on wild white-winged vampires in Trinidad, where I know I can find them. And I know where to get Diphylla (another vampire species) in Mexico...
Diphylla ecaudata the hairy-legged vampire bat
White-winged vampires also have a completely unique chemical defense. I would really like to colloborate with a biochemist on that one. It's all pretty exciting...
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