Thursday, January 25, 2007
Independant Research
For my independant project I am going to analyze some data that we are gathering in our lab on a project looking at the effects of different plant toxins on caterpillar development. One component of these experiments has also been to examine the immune response of caterpillars fed on varying toxic diets to encapsulation of parasitoid eggs. To do this, we have injected caterpillars fed on various diets with minute glass beads ( a proxy for eggs) and we are going to see if the encapsulation response becomes compromised for caterpillars fed on toxic diets. Hopefully, we will have some really interesting results, Im just hoping the analysis is going to be too intimidating!!
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4 comments:
Spooky,
Sounds like an exciting project!
See you tomorrow!
Cheers,
Rebecca
Sounds interesting! I'm curious, what is encapsulation - is this something that benefits the parasitoid eggs (e.g., protects them) or that protects the caterpillar? Some parasitoids are attracted to "nasty" hosts that eat toxic (?) plants, right? So would you expect the toxic diet to positively or negatively impact the parasitoids?
I'm curious to hear what you find out!
so what will the data look like? that might be the topic of your next blog entry -- maybe?
Thanks for the comments! Well, encapsulation is an immune response from the caterpillar that is triggered by the presence of a foreign object in the body. The way some caterpillars respond is by surrounding the object with layers of cells that eventually harden and melanize, therefore preventing the parasitoid from developing. So, the prediction is that caterpillars fed toxic diets are less able to encapsulate the eggs, which beneifts the parasitoid by allowing it to develop. This is PhD dissertation research by someone in the lab whom I helped over the summer. So, we are still waiting to find out the results. For the feeding effeciency part, the data will be analyzed using ANOVA and ANCOVA and to examine whether the diets had any affect on pupal weight. So the data set is basically the replicates (caterpillars), the treatments, (different toxins)and initial caterpillar and pupal weights. We will use ANOVA to test for differences between the treatments and ANCOVA to remove any nusicance effects differences in the inital starting weights on the final pupal weights. For the encapsulation data, which hopefully some of it will be done by the end of semester. We will dissect the caterpillars and measure the degree of melanisation using imaging software. This will provide a measurement based on the color, called an r value. The stats test would then be an ANOVA to test for differences in the r values between treatments....well these are my thoughts so far, who knows what other stats may creep in there!!
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