For my experiment I decided to test the effects of various commonly used compost materials on mosquito oviposition. Certain essential oils have been proven to either attract or repel mosquitoes, but often these extracts are difficult to come by especially in undeveloped/developing countries. Therefore, I wanted to find a natural repellant against mosquitoes that could easily be acquired. Another motivation was the fact that litter has become especially prevalent and is a major contributor to air pollution, so I wanted to determine if the rise of mosquitoes could be linked to an increase in poor disposal practices. Additionally, I was curious to see whether food scraps or compost organic matter left outside could have a negative effect on attracting mosquitoes or introduce an additional benefit for composting.
I predict that since bananas have a high sugar and potassium content then they will best attract mosquitoes for oviposition. Also, I predict that onions will be best at repelling mosquitoes, due to their pungent odor.
I created a total of 15 mosquito traps (I know that sounds a bit ambitious!) in groups of 5 with two groups being placed within the same AOI location and the other group placed at a different location. In each group, I tested the effects of orange peels, onion peels, banana peels, egg shells along with my control. I created a “DIY’ed” Ovitraps (because I realized I didn’t have enough plastic bottles lying around) using plastic cups instead. In each of my traps, I included 1 1/4 cups of tap water, 1 cup of grass clipping as bait and mosquito netting. For the orange peel and banana peel traps I added 1 tsp of each of their respective fruit juices to the container. I also had a half of a full orange peel and 1 banana peel surrounding the traps to maintain the scent of the fruits in case the juice became too diluted in the water. For the onion peel and egg shells, I included 1/4tsp of their solids pieces (I used a lesser amount than for the orange and banana traps because they were more concentrated in their solid form) to their traps and similar included a handful of onion peels and 1 full egg shell surrounding their respective traps. The control simply consisted of the bait and tap water, without any additional additives.
Traps were set in their locations on Wednesday June 15th, each group was either placed in my backyard, front yard or around a nearby lake within my neighborhood.
^ Image of all 15 of the traps, the compost materials placed on the opening of the trap was simply for the picture and were removed to be placed around the traps once they were set.
^ Setting Banana Peel trap near the lake
^ Orange Peel trap near the lake
^ Onion Peel trap in backyard
^ Egg Shell trap in backyard
^ Placing the traps in my backyard
When I was transporting my traps to the nearby lake by car, many of them tipped over and lost water.
Week 1 (6/19- 6/25):
Water evaporated from many of the traps, so I needed to refill several of them. Also, I realized that the netting I used had holes that were too small, which made it unlikely for the mosquito eggs to fall through. Therefore, I replaced all the nettings on my traps with a different kind that had larger gaps.
Week 2 (6/26-7/2):
Week 3 (7/10-7/16):
All traps had no trace of mosquito larvae or eggs, smaller insects were found instead . The Orange Peels and Banana Peels traps emitted a bad odor and the grass clippings used as the bait began turning yellow.
^ At home "laboratory" set-up
^ Here are pictures of "worm-like organisms"
I haven't determined what their classification is, but I initially mistook them for mosquito larvae!
^ Look how many of them there are!
^"Worm-like organism" underneath a microscope
^ Mosquito larvae from afar
^ I predicted these mosquito larvae to be "Aedes"
Several miscellaneous bugs were found in the traps including June bugs, spiders, and ants. The traps for Groups 1 & 2 were reset on Monday July 4th. The traps for Group 3 were reset on July 7th.
Traps were reset on Wednesday July 20th.
^Here are pictures of the mosquito larvae that I found this week. They were smaller in size and had shorter antennae than those found in the previous week. I again classified them as "Aedes"
My initial hypothesis proved to be incorrect, as most the mosquito larvae were found in the Orange Peel traps, instead of the Banana Peel traps. Throughout all the weeks, no mosquito larvae were found in the Onion Peel and Egg Shell traps, so the former may support my second hypothesis. Though, it is difficult to confidently discern which trap was most effective at repelling the mosquitoes since several traps had no traces of larvae or were populated by the"worm-like organisms" across the experimentation period. These unidentified creatures were commonly found especially in the Onion Peel and Banana Peel traps. When the "worm-like organisms" inhabited a trap, the mosquito larvae were not found. It is a possibility that one organisms may hinder the development of the other. This occurrence may be due to chance or competition for resources.
It can be reasonably be deduced that poor disposal practices of food scraps may contribute to the spread of mosquitoes, given the fact that certain materials were favorable for mosquito oviposition compared to others. Alternatively, certain items may also repel mosquitoes. Though, it is difficult to draw a firm conclusion without further research and experimentation.
Thank you to the NASA SEES program coordinators for giving me the opportunity to participate in this program and conduct hands-on research!
About the author: Sameen is a senior at Brighter Horizons Academy, Garland, Texas. This blog describes a mosquito trapping experiment conducted as part of the NASA STEM Enhancement in the Earth Sciences (SEES) summer high school research internship. 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 (http://www.tsgc.utexas.edu/sees-internship/).
