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SEES 2022: Mosquitoes Missing in Action

Guest blog: Aesha S.

Purpose:

The purpose of this experiment is to determine the prevalence of each container’s exposure to sunlight in attracting more mosquitos. My intent was to measure the difference in the preferences of female mosquitoes to lay their eggs in locations with more or less shade. 

Methods:

After some research, I was able to deduce that the most common mosquitoes in North Georgia (specifically near Johns Creek) are Aedes and Culex, with some Anopheles (since they are somewhat prevalent throughout North America). Since I was limited to what I had at home, I went on a search to find relatively larger containers, however, although I was able to find a large container in terms of height, it was difficult to find a container that was wide (like a plate).

Although this fact was not a factor of any part of my experiment, it was interesting to find out that the Asian Tiger Mosquito is the most common Aedes mosquito (Aedes albopictus) in my local area. 

If anyone is interested in reading more about the Asian Tiger Mosquito: According to the North Georgia Health District, “[Asian Tiger] mosquito species is not native to North America but was introduced in the mid-1980s through the import of used automobile tires from Hong Kong. Since then, it has spread throughout much of the eastern United States. It can transmit diseases of public health concern like Eastern Equine Encephalitis, Zika virus, West Nile virus, Chikungunya and Dengue Fever.”

For each of the three traps, I used large, opaque white buckets and cut holes on each side to insert a rope (sturdy but thin). I “attached” the buckets to my neighbor’s fence since we have a lot of deer in our neighborhood and they have a tendency to knock things down (as well as eat whatever they can find, unfortunately our rose bushes were recent victims). 

I filled each trap with the same amount of water to ensure that there were no other independent variables affecting the results. Each of the three traps was placed in a location with either direct sunlight, sunlight through sparse leaf cover, or shade. (Images 1, 2, and 3 - taken a few days after placing the traps in their locations since the first time they were placed in their locations, the sun was not out)

Image 1 (above)

Image 2 (above)

Image 3 (above)

Results:

By the end of the six weeks of my experiment, I was not able to find any mosquito larvae in any of my three traps. In the direct sunlight and shaded traps, though, I was able to find some other organisms and insects (Images below).

Disclaimer: I currently have an iPhone 13 which caused me to run into some issues of focusing the microscope when using the camera, so for the images with larger subjects, I took regular pictures to avoid losing quality. However, some of the organisms/insects were too small to take a regular picture so they had to be taken through the microscope, resulting in some unclarity.

Image 4 (left) shows what seems to a sort of caterpillar (based on the visual characteristics). I think it might have went inside because of the grass clippings that were blown into the buckets by the wind.

Image 5 (right) shows an unidentifiable organism (I tried taking a picture of under the microscrope but funny enough, when I had it laid out in the dish, it crawled away by the time I could set up the microscope onto my phone camera. Fortunately, I was able to zoom in on a picture I took of the bucket to include it in this blog.

 

Image 6 (left) shows an ant and a small piece of what seems to be bark. 

Image 7 (right) shows two insects/organisms that I have yet to identify. If anyone knows what these are, please let me know, I'm interested in finding out if they had some reason for being in the trap (other than it being a source of standing water).

There was likely some experimental error caused by the varying levels of rain and heat. There was two situations, once during Week 3 and once during Week 6 that the traps lost a lot of water either due to the heat or animals consuming this water (however, very unlikely). And there was one situation during Week 6 that the rain caused the traps to overflow, which more than likely killed any organisms or larvae (if present) that were on the surface of the water. There was some rain during this experiment (obviously since Georgia is nothing without the rain), I included some graphs below that show the rainfall during the June & July months to give a general idea of how much the traps might have been affected. I think there was probably a few instances other than Week 5 during which the rain caused the buckets to overflow but the excess water evaporated shortly after due to the sun. 

Below are my tables with the specific observations from each week for each of the traps. 

Trap 1              
Week Treatment Larvae Count ID? Experimental Error?
Notes & Observations
   
1 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
2 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
3 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
4 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
5 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass; unidentifiable insects/organisms
   
6 Shade 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass; unidentifiable insects/organisms
   
Trap 2              
Week Treatment Larvae Count ID? Experimental Error?
Notes & Observations
   
1 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
2 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
3 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass; caterpillar?
   
4 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
5 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
6 Slightly covered by leaves on the tree 0   Varying levels of Rain & high exposure to heat
No larvae, some pinestraw & grass
   
Trap 3              
Week Treatment Larvae Count ID? Experimental Error?
Notes & Observations
   
1 Direct Sunlight 0    
No larvae, some pinestraw & grass
   
2 Direct Sunlight 0    
No larvae, some pinestraw & grass; ant interacting with bark?
   
3 Direct Sunlight 0    
No larvae, some pinestraw & grass
   
4 Direct Sunlight 0    
No larvae, some pinestraw & grass
   
5 Direct Sunlight 0    
No larvae, some pinestraw & grass
   
6 Direct Sunlight 0    
No larvae, some pinestraw & grass; unidentifiable insects/organisms
 

 

Analysis:

I was stumped trying to figure out why the traps were not facilitating any mosquito larvae. After doing some research and looking out my window towards the neighbor's backyard (and the fence where the traps are located) I realized that it was most likely my neighbor's mosquito extermination service that prevented female mosquitoes from laying their eggs in the traps. The extermination service employees usually spray a thick mist of some sort of liquid (chemical I presume) in my neighbor's backyard and its is likely that the mist lingers and spreads throughout the general area, affecting my house's side of the fence too. I am still trying to research further to see if there are an other verifiable reasons for the lack of larvae, but at the moment it seems that the mosquito extermination is the core reason. 


About the author: ​​​​​​​Aesha is a rising senior at Northview High School, Johns Creek, GA. This blog Aesha Shahdescribes 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/).

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