What All the Buzz is About: Comparing Citizen Scientist and Professional Data Quality in Mosquito Monitoring

Article: Pernat, N., Kampen, H., Jeschke, J.M., & Werner, D. (2020). Citizen science versus professional data collection: Comparison of approaches to mosquito monitoring in Germany. Journal of Applied Ecology: https://doi.org/10.1111/1365-2664.13767

Mosquitoes on the Move: Motivations for Monitoring

Mosquitoes are on the move – our increased connectedness and travel among countries as well as changes in climate have spurred the movement of mosquitoes across a broader geographic region, including to places certain mosquito species were not previously found. Because mosquitoes often carry and may transmit pathogens to humans, this global mosquito invasion could have serious public health implications. The movement of mosquitoes has spurred various research and monitoring efforts, includes those using citizen science methods where mosquitoes are collected by non-scientists.

By 2012, for example, Germany had established a national mosquito monitoring program that combined professional data collection by scientists with data collected by citizens (“citizen science”). Both types of data had been pooled together and used to inform mosquito control, but until recently, no one had compared the data collected by scientists and citizens. Is the data collected by scientists better than the data collected by ordinary citizens? Nadja Pernat and her colleagues sought to compare these two approaches in the monitoring program in order to determine the answer.

Comparing Professional Data with the “ Mückenatlas ”

In 2011, researchers in Germany implemented a scientifically informed system to trap mosquitoes that are then identified. These traps attract mosquitoes to them by releasing carbon dioxide, as one way that mosquitoes detect humans is through sensing the carbon dioxide we produce when we exhale. Sixtyeight traps were placed throughout Germany across a wide range of land-use types (e.g., wetlands, urban areas, cemeteries, airports). From 2011 through 2017, approximately 130,000 mosquitoes were caught in these traps.

Close-up image of a white BG-Sentinel trap, which is used to trap mosquitoes
A BG-Sentinel trap (Biogents), which is used to trap mosquitoes.
Source: Bioquip Products

In 2012, the Leibniz Centre for Agricultural Landscape Research (ZALF) and the Friedrich-Loeffer-Institut developed a citizen science program (“Mückenatlas”) through which citizens could send in undamaged, collected mosquitoes for identification. This program started informally when citizens started sending in mosquitoes for identification anyway, before a formal program was established. Mückenatlas is flexible and accessible in that anyone can send in mosquitoes that have been trapped in any way at any time. The mosquitoes are then identified, and emails are sent to the citizens with more information about the mosquitoes. In the 8 years Mückenatlas has been running, over 25,500 citizens have participated, contributing approximately 138,000 mosquitoes in total.

To compare these two mosquito datasets – collected by professionals and by citizens – Nadja Pernat and her colleagues compared the species identity, abundance, and land use of places where mosquitoes were caught. In practice, both datasets are used to make decisions relating to invasive mosquito control.

Roles for Professional and Citizen-Scientist Data Collection

Both datasets (professional and citizen) were found to be useful, but in different ways. The mosquitoes collected by citizens represented a much wider range of municipalities than the traps: 3,221 municipalities, as opposed to 221 for the traps. Mückenatlas also included mosquitoes from private properties where traps could not be placed, substantially expanding the ground covered in the monitoring program. That said, a much higher proportion of the land-use types covered by citizens was from “artificial surfaces” and urban landscapes; because the professional traps were intended to cover a wide variety of land-use types, they were less biased towards urban areas.

Slightly more mosquito species were found in the professional traps, but citizens collected proportionally more invasive mosquitoes. This might be a result of information campaigns that triggered citizens to look out especially for these species, and the fact that citizens collected mosquitoes from fewer land-use types. By installing traps across land-use types in proportions equal to the proportions that those land-use types are found in Germany, the professional dataset had less bias.

Asian tiger mosquito (Aedes albopictus), an invasive mosquito species that was more often collected and identified in Mückenatlas than in the professional traps. Source: James Gathany, CDC, via Wikimedia Commons

Overall, both mosquito datasets conveyed different information, but complemented each other well. By developing a low-cost citizen science program, many more areas in Germany were monitored, and mostly areas where many people live. Having a scientifically rigorous monitoring program running at the same time helped provide a clear picture of how different mosquito species associate with different land-use types. Together, the disadvantages of each data type are offset by the others’ advantages, which makes for a solid monitoring program.

If you are interested in getting involved in citizen science, there are many efforts underway around the world. If you are interested in mosquitoes, consider checking out the partners that belong to the Global Mosquito Alert Consortium, and see if there are any citizen science projects in your area!

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Jenna Zukswert

I am a PhD student at SUNY College of Environmental Science and Forestry in Syracuse, NY. My research interests are in ecosystem ecology, biogeochemistry, and forest management, and I am interested in bridging the gap between those who conduct research and those who use the results. Twitter: @jzukswert

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