I’m located in Reno, Nevada. Reno’s climate is semiarid and Nevada is the driest state in the US. Additionally, Reno’s daily temperatures vary significantly: June’s average temperature high is 29 degrees celsius and its low is 10 degrees Celsius, similarly July’s average temperature high is 34 degrees and its low is 13 degrees celsius. In contrast, mosquitoes tend to breed best at around 29 degrees celsius and there are significant drop-offs in breeding as temperatures increase or decrease from 29 degrees. Furthermore, as a result of low vegetation in its semi-arid climate, Reno has very few shady areas and 300 days of sunshine. As a result of these three factors (which are not conducive to mosquito oviposition), mosquitoes are not commonly found in Reno. A prior SEES intern located in Reno supported this assumption by logging no mosquito larvae throughout the internship, finding only a few adult mosquitoes on the final day of logging in August. Therefore, in my experiment, I am investigating whether various types of bait make any difference to the baseline of very few to no mosquitoes expected in Reno. I have set up 5 different mosquito habitats, each with their own bait. The mosquito habitats contain:

• Tap water that serves as a control

• pond water collected from a nearby park to emulate that nearby habitat in my residential area 

• hamster food mixed with water

• Fish food mixed with water

• Grass, collected from the same park, mixed with water

The containers are 5 gallon Home Depot buckets, colored orange. They each have a wooden paint stirrer resting inside the bucket – about 1/4th of each paint stirrer sticks out of the water so as to provide a location for mosquito oviposition. The containers are lined up one after another and are all located in a shady area on a 3rd floor balcony. The placement on the balcony ensures the traps are in a shady area, remain undisturbed (enabling a still water environment), and are not subject to any pest control programs. 

Hypothesis: Since mosquitos are commonly found in nutrient-rich water with lots of food for larvae and pupae, the mosquito habitat with pond water will have the highest total number of mosquito larvae by the end of this experiment.

I check these traps every 5 days to see if there are any developments in mosquito larvae count. I will be updating this blog thread during the same interval with any new developments from the current mosquito and larvae count of 0. 

My mosquito traps are located in the same area as a previous SEES intern’s mosquito traps. By using a comparable methodology in my mosquito traps, I aim to provide continuity in the GLOBE MHM dataset for this area, so as to improve its usefulness for research using citizen scientist data. 

(view of traps)

Midway Update: 

Throughout my GLOBE MHM observations so far, I have not found any  mosquito pupae or larvae. The Culex mosquito species is one of the most prevalent mosquito species in Northern Nevada (Sandoval et al., 2017). Oda et. al (1980) observed that the rate of Culex mosquito oviposition is reduced at higher temperatures and that temperature plays a limiting role on the distribution of certain Culex mosquitoes. Chaves et. al (2011) observed that increases in average relative humidity resulted in increases on Culex oviposition. Therefore, I believe Reno’s high temperature and low humidity are the two main factors preventing mosquitoes from breeding in my habitats. As of late, the daily temperature highs have been between 35℃ and 39℃ (95℉ and 102.2℉) and the nightly lows have been between 16℃ and 21℃ (60.8℉ and 69.8℉). According to the Weather Underground, the humidity this past week has averaged at around 24%, which is considered low humidity. 

These two factors create an environment which is unfavorable for mosquito oviposition. I will continue to monitor the traps to see if any more developments occur. 

The following data set is from the Weather Underground, which indicates the low humidity and high temperatures of this past week.

Conclusion:

During my final GLOBE Mosquito Habitat Mapper log I found 10 adult mosquitoes in the water and on the paint stirrer of my Fish Food trap – photos are included below. This result was positive in that I was able to foster a mosquito habitat by the end of July, as did the NASA SEES 2021 intern in my area. Additionally, my mosquito count was nearly twice as high as the previous intern’s. This increase in mosquitoes found in my traps occurred right before wildfire smoke from the Oak Fire in Yosemite settled into the Western Nevada area. In the days preceding and following the wildfire smoke’s migration into Western Nevada, the range of temperatures experienced in Reno narrowed and humidity increased, which likely aided mosquito oviposition in my traps. However, the presence of adult mosquitoes only in the Fish Food trap rejected my initial hypothesis that, if able to proliferate, mosquitoes would prefer the pond water trap. Having previously discussed how mosquito-specific larvicide is often used in park ponds with NASA mentors, I hypothesized that such larvicide could be the reason behind the mosquito’s preference for the Fish Food trap over the pond water trap. In researching the use of mosquito-specific larvicide in Reno, I discovered that Washoe County has been conducting mosquito abatement sprays since May 5th, 2022 (ThisIsReno, 2022). Through the Washoe County Health District’s mosquito treatment data, I was able to confirm that the pond I collected my pond water from was sprayed with mosquito abatement insecticides within the last 30 days. Consequently, it was very likely that the pond water sample contained mosquito larvicide (Health District), providing an explanation for why the mosquitoes preferred the fish food trap instead of the pond water trap, as seen in previous GLOBE data recorded in my area. 

My findings hold valuable insights for mosquito surveillance efforts in Reno, Nevada – particularly as climate change results in increasingly unpredictable climate characteristics and natural disasters, such as wildfires and flash flooding (Sandoval, 2017). Continued mosquito surveillance in the Reno area is necessary to build up public mosquito surveillance datasets, as mosquito-borne disease is an increasingly important local public health threat. I believe government datasets on mosquito surveillance efforts should be made publicly available to encourage widespread research into Reno’s changing mosquito population and vector dynamics, like the project my NASA SEES research team and I conducted on LA’s West Nile Virus Infection rates https://youtu.be/47Nx2zozmR4. Citizens can contribute to this forward progress through regular contribution to NASA-funded citizen scientist projects, such as GLOBE Observer. 

References
 

Chaves, L. F., & Kitron, U. D. (2011). Weather variability impacts on oviposition dynamics of the southern house mosquito at Intermediate Time Scales. Bulletin of Entomological Research, 101(6), 633–641. https://doi.org/10.1017/s0007485310000519  

Health District, W. C. (n.d.). Program Services. Retrieved July 29, 2022, from https://www.washoecounty.gov/health/programs-and-services/environmental-health/vector-borne-diseases/program_services.php  

Oda, T., Mori, A., Ueda, M., & Kurokawa, K. (1980). Effects of temperatures on the oviposition and hatching of eggs in Culex pipiens molestus and Culex pipiens quinquefasciatus. Tropical Medicine, 22(3), 167-180. 

Sandoval, B., Phinney, C. L., Whitley, R., & DiMuro, J. M. (2017, June). West Nile virus what nevadans need to know - DPBH. Special Report Trends in West Nile Virus Nevada. Retrieved July 10, 2022, from https://dpbh.nv.gov/uploadedFiles/dpbhnvgov/content/Programs/ELC/dta/West_Nile_Virus/NDA_WNVBrochure.pdf  

ThisIsReno. (2022, May 6). Washoe County to conduct Mosquito Abatement May 5. This Is Reno. Retrieved July 29, 2022, from https://thisisreno.com/2022/05/washoe-county-to-conduct-mosquito-abatement-may-5/