My Shadowing Experience

            As a science student who is involved in research studies, I have extended my horizon of scientific understanding and learning by shadowing a colleague who is engaged in a totally different field of studies. I have got the opportunity to shadow Cara Marie Voelliger in her experiment on fruit flies, Drosophila melanogaster, to study how they get affected by the presence of different concentrations of cadmium in their environment. First of all, the fruit flies are chosen as the subject of this study as they are the most common and important model organism in modern biology. To do this, she has run numerous, long term trials of observing the characteristics of a virgin male and a virgin female fruit flies in each of several vials which contain the different concentrations of the cadmium. In this experiment, Cara is mainly looking for the copulation/mating of the flies in the vial. The length of each observation lasts for 30 minutes. I have noticed that it is a really interesting topic to study but, in the meanwhile, it also can get so boring and frustrating as the scientist has to focus on it for that time interval and gives each and every move of the flies an undivided attention with highly crucial timing of the specific activities.

            Other studies that have been done in the past imply that heavy metals (i.e. including cadmium) have a non-linear and fluctuating effects on the behaviors and sexual orientations of these organism. According to these studies, fruit flies could easily get stroked by the application of low and high concentrations of the heavy metal; but, surprisingly they do not recognize the presence of the medium concentration. There are no justifications and reasonable explanations to this phenomenon yet. This is not what Cara is also trying to investigate. It helps anyone to understand and accept the possible results though. In general, heavy metals, most likely, affect the fruit flies by varying the amino acid in them called methionine. Some studies have shown that dietary methionine can modify lifespan in adult female, fruit flies fed a synthetic food with carefully controlled amino acid, sugar and nutrient content.* This actually has nothing to do with Cara’s research but it implies another characteristic feature of the amino acid within the same organism used as a study subject in her experiment. But it might just open a door for another research and I believe that is not Cara’s interest at least for the time being.    

            Currently, Cara is working with 0.75 mM cadmium which is the highest possible concentration that would allow the fruit flies to stay alive for the research. So, it is most likely that this concentration has a negative effect on the fruit flies as it is close to becoming deadly against them. She has also tested 0.1 mM cadmium in the past and her observations report that the flies were negatively affected by that concentration. In the other hand, a medium concentration, 0.5 mM, cadmium has not shown any significant difference from the wild type flies. Therefore, even if we cannot tell the reason, low and high concentrations of cadmium have negative results while medium concentration of cadmium has no known negative effect so far.

            Supported by the theory and background studies that have been mentioned above, Cara is not seeing any copulation in any of the 0.75 mM cadmium vials. There is actually unlimited number of possibilities for the results to come out this way in addition to the toxicity or hallucination that the cadmium might have been causing to the flies. Ether is also a major part of the procedure in this experimentation and over-ethering the flies might have a long term effect on them so that its effects on the behavioral changes of the flies might be expressed later during the time of the observation.

The length of the time of copulating is another factor to be tested in this laboratory set up which is actually being done as a side support of the observations. As different heavy metals and different concentrations have different effects on the behaviors of the individuals which are involved in the vial, every factor should be tested and the degree of the influence should also be known to the possible depth. During her observations, Cara looks for minute details that might be done by the flies such as: preening which is the cleaning up process by a fly, singing to attract the female, sight and chasing after the female around the vial, touching/tapping the female, and all the other several suspicious activities for copulating and ‘normality.’ Specifically, any type of contact has to be awarded a major attention by the scientist as it is not any simple physical contact happening between the two but it is most likely a chemical transfer by the male via its extended proboscis to lick the female’s genital area and trigger sexual feelings which would allow its dear request for mating instead. In this experimental community of the two, the female has a total presidency over the male when it comes down to copulate. It is all up to the male to seduce the female in any possible way to mate with.

In comparison to my research, this research that Cara works on has very few similarities and several differences to mine. To start with the similarities, both of us are holding some previously done research results as our background information and we both have that checkpoint to come up with a critical thinking approach of tackling the problem that we are trying to solve in our research projects. The various variables, especially the controls that we have included in our studies' also make our research projects' somewhat similar as we both have something to use as a point of reference. On the contrary, our differences start from the fields that we are researching: Cara's behavioral science and toxicology versus my cell and molecular biology. I deal with micro studies while she deals with the bigger picture. I would also say that Cara has some specific hypothesis that she has based research on while I have a goal as most researches do but I would not certainly say that I have a specific hypothesis to relate my research to. These are the very few similarities and differences that I have noticed during my shadowing experience. 

 The involvement of the human emotion from the scientists’ side is likely in behavioral studies such as this one. Most biologists argue that it should be eliminated as much as possible as it would create bias into the observations made and then the results as well. Basically, it is difficult and almost impossible to eliminate one’s emotion and thoughts but it is also a great thing to understand and accept the truth that this experiment has subjects which are not humans, even if they have minor similarities, so that we cannot and should not treat them or interact with them as of humans. Therefore, we should not expect the flies to act in a certain way or react to a factor in any types at any time throughout the experiment; as none of us can do that. This actually reminded me of the article The Brief history of the Hypothesis that I have written a blog about last week when it comes to the point about how our assumptions might influence our results. They would possibly change the results and findings of the experiment to any extent. The solution, in my opinion, is to eliminate them as it is almost impossible to exclude them being a human.

Literature Cited

*Troen, A.M., French, E.E., Roberts, J.F., Selhub, J., Ordovas, J.M., Parnell, L.D., Lai, C. 2006. Lifespan modification by glucose and methionine in Drosophila melanogaster fed a chemically defined diet. Age.29:29-39.