Science Cafe Posts

SEES 2022: Mosquito Counting

Guest blog: Asher J.

In this experiment, I will be exploring how geoposition, type of bait, and container size influence female mosquitos’ choice of where to lay their eggs. 

Experimental design

There will be a total of 5 traps. Three of the traps will be positioned at a location near my house. They will be separated by a reasonable distance in the same type of environment to minimize the experimental error caused by having multiple breeding habitats in close proximity. The other two traps will be positioned in various locations in my land cover area of interest. The exact locations will be detailed below. 

The two variable geoposition traps will be identical with the control trap located near my house, to isolate the geoposition variable. Each will consist of a paper cup with one cup of distilled water and a handful of lawn clippings.

 

The three traps near my house will be used to test the effects of container size and type of bait on mosquito breeding preferences. The control trap will use the standard container size (paper cup) and standard bait (lawn clippings). The variable bait trap will use a standard container but contain tanbark and water, instead of lawn clippings and water. The variable container size trap will use the standard bait, but will be made out of a much wider bowl.

Geospatial Coordinates

1) (37.5094857 N, -121.9318311 W)

2) (37.5076545 N, -121.9273914 W)

 

Update 1: 07/08/2022

I checked up on the traps four days after setting them up. 

Of the three traps that were placed near my house, none contained any mosquito larvae. I also did not observe any eggs on the sticks that I placed in each of the ovitraps. However, I did notice that the trap containing the variable bait (tanbark instead of grass) had an ant infestation. This is probably due to the fact that the water was clear (unlike the containers with grass) and the ants needed a source of water. It is also possible that ants are attracted to wood; either way, none of the other four traps that I set out had any ants. Both the large container and the control trap contained a few dead mosquitos. I took out all of the ones I could, and observed them under my microscope. The pictures are shown below.

The two traps that I placed in various locations fared similarly. With the exception of a few dead bugs in the second trap, the contents were identical. 

In order to maintain the sustainability of my traps, I replaced some of the dead grass inside each one, and added water to make up for the amount lost to evaporation. 

 

 

Update 2: 07/12/2022

After another 4 days, I went back out to check on my traps.

The results are the same as the ones I got on 7/08. There are no mosquito larvae or eggs visible in any of the cups. However, I did find the wings of a mosquito that (presumably) died. 

It's worth noting that there were many experimental errors in this round of observations. When I approached, I saw two birds quickly fly away from their perch on the variable container size experiment. Sure enough, the water level had dropped much more compared to last time. 

The ants that invaded the variable bait cup mostly moved to the control cup. There were about 10-15 ants at the water line, drinking from the cup. I observed the mosquito wings in this cup, leading me to infer that the ants may have killed or consumed the mosquito. 

I checked with a few acquaintances who live in my area, and they also confirmed that their traps weren't having any success. From my own observations, I haven't gotten bitten by a single mosquito this year yet, when in past years, I'd be covered with bumps by now. It's possible that the specific design of the traps that I set out are just not preferred by female mosquitos, but it could also be that the mosquito population in my area has heavily diminished this year due to some unknown reason.

 

As a side note- This experiment is helping me keep up with my workout routine! I placed two of the traps about 3 miles from my house, so every 4 days, I'm forced to take a decently long bike ride to check on them. Unfortunately, this week I happened to roll into a field full of spiky weeds. Here's a picture of the mess that I spent 15 minutes dealing with.

 

Update 3: 7/18/2022

I checked up on the traps, and the results were similar to last time. The ant infestation returned after I cleared them all out, and there were once again a few dead bugs in the water. The variable bait container was tipped over, and the water spilled out. Of the other two traps, neither had any mosquito larvae inside, despite me leaving them out for longer this time (6 days instead of 4). I believe that there was probably a systemic error in my experimental design that led to no mosquito larvae throughout the duration of the experiment. Some potential errors include using cups that may be too small (I poured a cup of water in each one, but barely), and allowing other bugs to have access to the traps, which may have deterred any mosquitos in the area. 

Conclusion:

This experiment was originally designed to test three variables (bait type, location, and container size) and their effects on mosquitos' breeding preferences. After over a month of testing, I have been unable to obtain conclusive evidence to show that any combination of the aforementioned three conditions is more or less preferable. 

As with all science experiments conducted in the real world, this one was subjected to lots of experimental error. I did not account for the possibility of other species invading the traps, and potentially skewing the results heavily.


​​​​​​​About the author: Asher is a rising senior at Irvington High School in the Bay Area of California. This blog describes a mosquito trapping experiment conducted as part of the NASA STEM Enhancement in Earth Science (SEES) summer high school research internship. This 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/). Asher shared this experience in this blog post.

More Blog Entries