Pill Bugs & Soil Pollutants: Research Update
Determining the short-term effects common soil pollutants have on A. vulgare
Research Update
By Bethel (Betty) Berhanu, Julio Gonzalez, Lydia Mikhail, Mackenzie Whittall
| Figure 1. Photos of test subjects attempting to escape the test environments with pollutants added during the second trial. Photos were taken by Lydia Mikhail. |
Research Question & Hypothesis:
What sample pollutant has the most negative effect on A. vulgare (pill bugs)?
We hypothesized that the pill bugs would show signs of stress when exposed to common soil pollutants in a controlled sample environment. We predicted the pill bugs would show the most amount of stress when exposed to the sample environment with a pesticide because the purpose of this product is to repel and/or kill insects and other species that may feed on or harm plants.
Discussion:
So far, we have found that pill bugs do not like polluted soil. As we were observing the pill bugs, in almost all the polluted soils except the control, which was water, the pill bugs were trying to escape. As we increased the concentration of the pollutant present in the soil, the pill bugs started to slow down and were continuously trying to escape. We noticed that all of the pillbugs in the polluted environments would gather towards the edges of the container. As opposed the control, where the pillbugs would go towards the center and not gather as much. Even though there were no fatalities, we were able to interpret their behavior as discomfort.
One of the first challenges that our group encountered was figuring out a common soil pollutant that was not hazardous waste and could just be thrown away. It was difficult to find an alternative to our permethrin pesticide and motor oil that was still a common soil pollutant. During our experiment, our first trial did not go as planned. We predicted that the pill bugs would have a more extreme reaction to the pollutants we put in their soil. As we did our first trial, the pill bugs were not noticeably harmed by the pollutants, but we could tell that they did not like it because they did try to escape. We decided to increase the amount of pollutant in the soil in our second trial to assess whether or not it would increase the reactions (possibly fatal) of the pill bugs.
Advice that we have for other groups is to have a complete procedure/schedule walking into the experiment so you don’t run out of time as we did on the first day. It’s important to come up with a total testing time that your group thinks is large enough to record good data and is achievable in the time allotted. We also suggest dividing the work evenly among group members. We decided to have each member of the group watch one group of test subjects: it was much easier and more efficient when we observed the groups like this. We decided as a group to use different test subjects for each trial (except for the beginning control trial 0), as we did not want to use pill bugs that had previously been exposed to pollutants in order to keep the results as unbiased as possible.
In our error analysis section, we are going to discuss the differences in our setup for each day of trials. We did the trials on different days due to time constrictions in our lab, and the soils we used on each of the days had different starting levels of moisture. We took this into consideration when deciding how much liquid to moisten the soil with. We are also going to talk about how our prepared pollutant solutions, including the soap and tobacco solutions, were also prepared on separate days and could have varied in concentration compared to the solutions used in the first trial.
One of the first challenges that our group encountered was figuring out a common soil pollutant that was not hazardous waste and could just be thrown away. It was difficult to find an alternative to our permethrin pesticide and motor oil that was still a common soil pollutant. During our experiment, our first trial did not go as planned. We predicted that the pill bugs would have a more extreme reaction to the pollutants we put in their soil. As we did our first trial, the pill bugs were not noticeably harmed by the pollutants, but we could tell that they did not like it because they did try to escape. We decided to increase the amount of pollutant in the soil in our second trial to assess whether or not it would increase the reactions (possibly fatal) of the pill bugs.
Advice that we have for other groups is to have a complete procedure/schedule walking into the experiment so you don’t run out of time as we did on the first day. It’s important to come up with a total testing time that your group thinks is large enough to record good data and is achievable in the time allotted. We also suggest dividing the work evenly among group members. We decided to have each member of the group watch one group of test subjects: it was much easier and more efficient when we observed the groups like this. We decided as a group to use different test subjects for each trial (except for the beginning control trial 0), as we did not want to use pill bugs that had previously been exposed to pollutants in order to keep the results as unbiased as possible.
In our error analysis section, we are going to discuss the differences in our setup for each day of trials. We did the trials on different days due to time constrictions in our lab, and the soils we used on each of the days had different starting levels of moisture. We took this into consideration when deciding how much liquid to moisten the soil with. We are also going to talk about how our prepared pollutant solutions, including the soap and tobacco solutions, were also prepared on separate days and could have varied in concentration compared to the solutions used in the first trial.
Questions:
- How many fatalities have other groups experienced?
- Did their predictions come true? If not, how different were their results?
- Do you think your results would be different and/or more dramatic if the experiment lasted longer?
- What would you change if you were to do the experiment again?
- How do you think the results would differ if you performed the same experiment with a different species?
Hello guys,
ReplyDeleteYour experiment looks really interesting and fun to run! I am pretty sure that watching pillbugs trying to escape their containers must be entertaining. Concerning your advices for other groups paragraph, I totally agree with the first one mentionning the importance of a schedule! If only my group knew this advice at the beginning of our experiment, it would have been so much easier. Overall, your project seem to have reliable results and I will be glad to learn more about them during your presentation.
My group also had issues with time constraints. In our case this was caused by the inability to locate or capture Daphnia for observation. Also, when you assigned each group member to a different pillbug population, did you have the same person observe the same population each time, or did you alternate between them? I ask because given the potentially subjective nature of interpreting significance in pillbug behavior, there is likely some variation in the way this data was reported. You may want to address this in your error analysis.
ReplyDeleteHey! So we did something similar to you guys with additives in soil and pill-bugs. However, we used organic fertilizer, coffee grounds, and pesticide. Still, we did not see what you saw with your bugs avoiding the polluted soil. In fact, our pill-bugs actually sat in the pesticide portion of our choice chamber without caring really. It's probably because you guys used maybe harsher chemicals? I still don't get why ours liked the pesticide. Anyways, interesting observations with your bugs.
ReplyDeleteHello, nice update. I believe most groups had issues with time during this experiment, including our group. My question would be how many trials did your group have? Based on your update I know that you had at least two trials considering you write about having a second trial. I was wondering if you had anymore or if your group had enough data based on those two trials. It seems like your prediction came true in a way. Since in the end the pill bugs were uncomfortable and distanced themselves from the soil; they must have been showing a high amount of stress. Good work.
ReplyDeleteIt's nice to see an experiment that does not have their subjects die on them! When you stored your pillbugs away, did you give them enough of an airway so they can breath? Also, did any of them roll up into a ball? I'm very curious to see all of the variables that you encountered while making this experiment. My group struggled the most with finding our Daphnia as time went on because more continued to die on us and we had to slightly modify our hypothesis a little bit.
ReplyDelete