For 4 weeks this summer, much like other Earth Explorer interns, I built a few mosquito traps and set them out near my home within my AOI. I’m located in sunny Plano, Texas, near a creek. To set up my traps, I first bought 4 large, 2 Liter soda bottles, drank a small bit, and emptied the rest out. I know we shouldn’t eat in the lab, but let’s just say the experiment started after the bottles were emptied. Then, I cut them in the middle and sanded the top halves near their mouths to make them a bit rougher. I got some net from a loofah and tied it to the mouths, then inverted the top so it would fit snugly into the bottom half.
I needed an independent variable, so I decided to vary the water type based on things that are common in my environment. For the first trap, I used simple tap water. For the second trap, I put peels from one whole mango into some tap water (shown below). The mango flesh itself was a nice treat in the summer heat as I was setting up my traps :) . It’s important to note that these two traps mimic things that I’ve noticed near my home. For example, water like the tap water can collect near hoses or in buckets outside, and fruit water may be common near composts, gardens, or even in the soil near trash bins.
Note: Each sample was about 3 cm tall in water level when placed in the identical bottles.
For the next two samples, I decided to use some water from the pond near my house (picture below), since the still-water there has been known to attract mosquitos in the past. The same can’t be said for humans though, because the creek gets incredibly stinky once the temperatures start climbing. In fact, the pond water there grows huge algae blooms in the summer months, and since that coincided with the general mosquito ‘season’ where I live, I thought it would be interesting to observe the effect algae had in the samples, too.
So, for my third sample, I filtered out the pond water without the algae, and for my fourth sample, I left the combined water as I took it from the pond surface. The samples smelled so bad that I didn’t want to bring them into the house, but I held my breath and persevered in the name of science.
Additionally, I read that mosquitoes tend to favor dark areas to lay eggs, so I decided to put these samples each in their own black, plastic pots. This had the added benefit of making sure the traps remain stable and upright throughout the sampling process. (top view/side view below:)
I was also curious about the chemical composition of the water samples I used. In an ideal world, I would bring these samples to something like a mass spectrometer and compare the results. However, I’m a high school intern working from my backyard, so I used what was cheap and accessible - pool water strips. I picked these up for a couple dollars at my local home depot and tested each of my samples.
1 = Tap water, 2 = Tap water + mango peel, 3 = pondwater (no algae), 4 = pondwater (with algae)
There wasn’t too much of a difference between the first 2 samples except for the pH and alkalinity, which is to be expected with the mango peel. The tap water in both was harder than the pond water from samples 3 and 4, which is also understandable (Texas tap water is on average, the 6th hardest in the nation). It was interesting to note that the third and fourth pond samples had higher alkalinity than the tap water samples.
Of course, these tests are quick and dirty, and they’re meant for chlorinated pool water within a small range of pH values, so they are bound to have a large error margin. However, they do provide an idea of how these water samples compare relative to each other (and make me feel like I’m some mad scientist chemist working in a lab).
I placed my samples under some shrubs outside my house in a shaded area, like this...
...and then I waited!
So, after all of this preparation, what were the results? Well, for the first week, I had some high hopes, but I got:
I figured maybe my mosquito traps just needed to become one with their environment for a little longer, but in fact, the streak of 0’s continued for the next 3 weeks.
Note - I replaced the mango peel after the second week because of rotting and mold growth.
After the fourth week of testing, I caught a fruit fly in trap #2 (fitting, considering the mango peel inside), but no such luck with mosquitoes. Although I was initially disappointed that none of my traps seemed to work, I later stopped to think about why that was:
For one, my area is experiencing a record breaking heat wave right now. The creek by my house has dried up far more than usual. We’ve had a heat advisory for weeks, with daytime averages this July above 100 °F more days than not. After a bit of research, I learned that, although mosquitoes are known to come out in the hot summer months, there’s an upper cap to that heat, too. According to a 2019 research paper titled “Thermal biology of mosquito-borne disease” (Mordecai et al), mosquitos struggle to survive at temperatures above 38 °C, which is roughly 100.4 °F. There’s no surprise then, that it was hard to find mosquitoes in my traps.
Additionally, after a Zika outbreak a few years ago, my city regularly conducts mosquito spraying on a yearly basis in preparation for the summer months, so if anything, the lack of mosquitos in my traps may suggest that these protection methods are working.
So, as much as I know my neighbors appreciate having no mosquitoes flying around near their homes, maybe science might appreciate my anti-climatic experiment results, too. Even though my tests varying water samples were inconclusive, they do demonstrate the reality of how uncontrollable environmental factors can affect the experimental process. Additionally, they may highlight the effectiveness of local mosquito containment methods already in place. My streak of 0’s may just be useful, after all.
Thank you to our internship mentors who advised us through the past few weeks. I really learned a lot about science and my environment!
About the author: Rhea is a high school student attending Lebanon Trail High School in Frisco, Texas. Her virtual internship is part of the 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 schoolers (http://www.tsgc.utexas.edu/sees-internship/). In this guest blog post, she shares her experience setting and monitoring mosquito traps in an experiment conducted in Plano, Texas.
