She Ate What?!

I want to go into a little more detail for my study so that I can relay an interesting occurrence that took place yesterday. A priority pattern study investigates the multiple mates of a female and their respective reproductive successes. Most insects have a second male advantage meaning that the second male with whom a female mates fathers more of the offspring than the first male. In spiders, however, there is usually a first male advantage. I am going to directly (I hope) test the priority pattern for Nesticodes rufipes. The design for the experiment includes controlling the number of intromissions (insertions) the male makes when mating, which linearly correlates with the amount of sperm that he releases. I will have two types of males: 1) Normal fertile ones and 2) Sterile ones. The sterilization process is an interesting one in itself. Basically we irradiate the male, which leaves his sperm intact, but scrambles the DNA of the sperm leading to infertility. I will have four groups. The first control group will involve mating a virgin female with two fertile males. Then the control for the irradiation process will involve mating a female with two sterile males. The last two groups involve alternating the mating order of one sterile and one fertile male. Then the amount of offspring produced in the experimental groups will help to elucidate the priority pattern. I might try varying some of the number of percentage of intromissions of the two males (ie: 50/50, 25/75 & 75/25) just to see the results.

I currently have been in the process of trying to foster a breeding colony for my spiders so that I can produce a large enough sample size for controls and manipulations. Nesticodes rufipes is a species that is generally found indoors of laboratories, prey rooms of zoos, and perhaps barns. E.O. Wilson had these babies in his lab when he was doing his ant research. Anywho, these spiders mate for a total of 3 hours!! Talk about stamina! What takes so long? Well, the sperm producing organs are found in the lower abdomen of the male, but his organ of copulation are palps on his antennae. He has to build a sperm web and then dab his palps in it (called induction) so that he can then inseminate the female. It is a curious process because during intromission, he inserts one palp and basically turns the female in a semicircle. Then he switches palps and turns her the other way. Imagine a much bigger female just calmly putting up with this turbulence! Anyways, I put in a male with my most aggressive female yesterday and came back three hours later. She had mated with him, and then decided she was hungry and spun him up in her web. This is not the most common behavior but it does happen on rare occasions. I guess I am glad to be breeding some hearty stocks, but males are hard to come by and I would rather my females not consume their mates. Thought you all would find this amusing!

Hamilton and Altruism

In my evolutionary psychology seminar, I just got the chance to read one of W.D. Hamilton's papers. This is the first time that I have actually read him directly. Of course, he is a staple in evolution and ecology courses with his theory of inclusive fitness as a means to explain "altruistic" behavior. I have always found his exploration of natural selection at the level of the gene and its effect on social behavior quite fascinating. The great thing about reading him was his very straightforward writing style. Imagine such complex ideas with mathematical models and all being lucid! The man is a good writer. Anywho, I know that a lot of mathematical manipulations have been done to test his theory of altruism with current ecological data and that it holds up pretty well. Anyone have an idea of what these statistics look like? How exactly would you assign a numerical value to the cost to the altruist or the benefit to the recipient? These, unlike a coefficient of relatedness, very hard to quantify. It would be really interesting to examine an ecological study that tests Hamilton's theories. Anybody know of a good one?

Science and the ladder of progression

While reading G&E Chapter 1, I very much enjoyed the footnote about molecular biologists and how uncomfortable they are with uncertainty. The funny thing is that I continually have the hard vs. soft science debate on a regular basis. My boyfriend was a biochem major who is getting his PhD in Molecular Biology. So when I get excited about what I think to be a great experimental design for some ecological phenomena, he just picks it apart. There aren't enough controls or it cannot be manipulated directly! And blah, blah, blah! It drives me crazy. I continually tell him that the study of macro organisms in biology has a lot more variation. There is much more unknown. The uncertainty drives him crazy, but I find it so interesting. It makes interpretation so much more complex and many ideas must be considered and explored. Perhaps we may never know the answer. Obnoxious or thrilling? If everything was consistent and predictable, what puzzles would we grapple with? Not that molecular biologists don't have puzzles, I just think I find them a little on the boring side.

Independent Research

I think I want to do my project for this class on the priority pattern study on Nesticodes rufipes that I happen to be conducting for my honors thesis. Nesticodes are spiders by the way. I think looking at potential methods of analyzing data with statistics could really improve my design. Wow, and to think that this project will help me with something I already need to do!