SEES 2022: How does Water Level Effect Mosquito Likelihood

Guest Blog: Elizabeth Gorman

Conclusion: Although no mosquitoes were found, this process has helped me understand the methodology of making an experiment and having to deal with hardships and setbacks. There were many potential sources of error both within the system of the experiment and with outside forces. Systematic errors could have stemmed from the trap design or location. The weather was a factor of random error. The weather varied across the duration of the experiment, sometimes drastically within a single week. The weather changes could have been counteracted with more frequent checking of the traps. 

Notes on methods: Over the course of the experiment the water level changed, and so it was required to top up the water level. In order to not disturb the traps more than necessary, the water/tea solution was poured in slowly over a spoon to minimize the surface agitation.





Image Description: Particulates that settled into the traps.








​​​​​​​Image description: The high-water level experiment a few days into the experiment. Dirt, small rocks, twigs, and other small particulates have collected in the trap. (I decided to not clean them out because I thought the extra disturbance would be detrimental to the experiment).






Image description: One set of traps set up, without sticks (added later). The high-level water experiment is farthest from the camera. The low-level water experiment is to the left. The medium-level experiment is in the middle.







Hypothesis and Reason for testing: I hypothesized that the traps with a higher level of water will have fewer mosquitoes because wind and breezes would cause too much of a disturbance for mosquito larvae to grow. I have always been told that mosquitoes are unable to grow in moving water, but this experiment is designed to try and identify how much surface-level movement the mosquitoes are able to tolerate. The highest level of water, although still 3cm from the lip of the cup, would likely have the top layers blown away from a gust of wind. As for the lower levels of water, it is unclear if medium agitation plays as big of a factor as little to no agitation. San Francisco (where the experiment takes place) is fairly windy in the Summer, so although I did not keep track of wind speeds for each individual day, the wind speeds would be the same for each set of traps, and would only differ for the levels of water, as the experiment intended. 

Bait and Set up: The bait used in my mosquito trap was unsweetened peach tea. The tea was mixed with the water of the traps in approximately a 5:1 water-to-tea ratio. Across the weeks I had to add slightly more tea and water to each of the traps, and I tried to maintain the ratio each time. Two trios of traps were made, two with a high water level, two with a medium water level, and two with a low water level. A singular trap held approximately 30oz of liquid, but none were filled to the absolute full capacity. The trap for "high" water level was filled to approximately three centimeters below the brim. The trap for "medium" water level was filled to approximately ten centimeters below the brim. The trap for "low" water was filled to approximately 20 centimeters below the brim. I placed each trap with a ruler as the wooden stick. Each trio of traps was clustered together with the aim of them experiencing the same environmental factors.

Explanation of Personal experimental error in my data: I put my traps in the garden which is adjacent (and part of) the apartment that I live in. I set up three buckets next to the fence at the start of week two. After a handful of days, the neighbors in my apartment building were concerned about the appearance of three "suspicious buckets". I had to take the buckets away. The other tenants and I were able to compromise that I could use three medium-sized flower pots. I set these pots up around the start of week 4. Part way through week 4, they got dumped out by gardeners, and a day or so later I put the buckets back with a sign. I acknowledge that this is not the most formal beginning of my blog, but it is important because it explains experimental errors and inconsistencies in my data.

Here is an indication of where my buckets were before I put the pots out. 




About the author: ​​​​​​​Elizabeth is a high school student. Her virtual internship is part of a collaboration between the Institute for Global Environmental Strategies (IGES) and the NASA  Texas Space Grant Consortium (TSGC) to extend the TSGC Summer Enhancement in Earth Science (SEES) internship for US high school ( Elizabeth shared her experience this summer in this blog post.


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