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Study Confirms Effectiveness of Cheap, Simple Traps for Citizen Science Project

An exotic ambrosia beetle (Xyleborinus saxesenii). This was the most common beetle in the traps, and is in fact the most common ambrosia beetle in North America, even though it originates from the Palearctic region. Photo by Jiri Hulcr.

By Kaine Korzekwa

By asking members of the public to capture and send beetles in for research, scientists at the University of Florida are using “citizen science” to get a better idea of the distribution of invasive beetle species in the southeastern United States.

Kaine Korzekwa

“It’s actually very hard for scientists to do a large-scale project or survey in private areas,” said Andrea Lucky, a professor of entomology and nematology at the University of Florida. “Creating a network of people to help with data collection can greatly increase our capacity to study where these bark and ambrosia beetles are.”

But getting help with data collection is only half the story. The group is also trying to create transparency in science and to get people involved in the scientific process.

The beetles in question are bark and ambrosia beetles, both extremely damaging forest pests that threaten timber and fruit-tree industries worldwide.

Bark beetles damage trees by digging under the bark and getting into the phloem, the part of the tree that circulates sugars and other nutrients. They become a problem when their numbers become so large that they overwhelm trees and kill them.

On the other hand, ambrosia beetles burrow deeper into the xylem tissue — the part of the tree that circulates water – where they leave fungus spores. The fungus grows and the ambrosia beetles eat it, which is good for the insects but is deadly for the trees.

In their native ranges, the populations of both species are usually relatively low, and they are mainly known to attack trees that are weak, dead, or dying. However, that does not seem to be the case outside of their native ranges, according to Sedonia Steininger, a graduate student at the University of Florida.

“For reasons we don’t really understand, some of them attack live trees when they are outside their host range,” Steininger said. “This makes them really problematic as an invasive species.”

She added that the ambrosia beetle has been found in parts of the southeastern U.S., where it’s posing a risk to fruit trees, especially avocados. They can also be a problem in urban landscapes, where they can kill street trees and pose a risk to power lines and homes.

To protect trees it’s important to swiftly assess the distribution of these beetles, and that’s why Lucky, Steininger, and Jiri Hulcr, also at Florida, have turned to citizen science. In 2013 they launched the Backyard Bark Beetles project, which allowed non-scientists to participate by testing the effectiveness of a simple trap they developed to capture the beetles. The results have been published in the Journal of Economic Entomology.

A two-liter soda bottle used to trap bark beetles and ambrosia beetles.

The trap consists of a two-liter soda bottle and an attractant. The study found that a trap with just one window cut into it performs just as well as painted traps or traps with multiple windows. They also found that 95% ethanol was the best attractant, followed by Purell hand sanitizer (75% ethanol) and Germ-X hand sanitizer(63% ethanol). This allows the public to use these cheap, common items instead of professional traps, which can cost more than $50 each.

“Since most people don’t have access to 95% ethanol, this is great news,” Steininger said. “What these new developments show is that the protocol is robust to small changes, which makes it great for citizen scientists.”

To the beetles, ethanol smells like rotting wood so they are attracted to it. More than three quarters of the specimens caught during the study were non-native.

The researchers highly value the two-way interaction between themselves and those helping them collect the data.

“After they send us their beetles, I identify them and put them on our project website’s distribution map, and they can then go find their location, click on it and see pictures of the species of beetles they caught,” Steininger explained. “They can see in real time the creation of species distribution maps. They can also click on the locations all around them and see what other people have caught in their areas, so it’s really cool.”

While the benefits of citizen science are numerous, there are some disadvantages to the idea. Lucky noted that it can be hard to secure funding for participatory science projects, and there are often questions of data validity since it’s not being collected by trained scientists.

“Rather than just saying ‘we think people are going a fine job,’ we took a scientific approach to the data collection and validation, and that’s how this trap study came about,” Lucky said.

The group said a lot of their work is contingent on the next collecting season because the project is ongoing. They are preparing a large outreach push to try to get people involved in the project and encourage everyone to check out their website:

“People’s observations are so powerful,” Lucky said. “Although some think it can be problematic, I think citizen science and public engagement is a powerful way to move forward.”

Read more at:

Simple and Efficient Trap for Bark and Ambrosia Beetles (Coleoptera: Curculionidae) to Facilitate Invasive Species Monitoring and Citizen Involvement

Ambrosia Symbiosis

Kaine Korzekwa is a master’s student in the Department of Life Sciences Communication at the University of Wisconsin-Madison and a freelance science writer. Armed with degrees in both biology and journalism from the University of Texas at Austin, he took off to the Midwest and is taking it one polar vortex at a time. He enjoys writing about anything in the life sciences and is interested in how the media helps people perceive the environment around them. You can reach him on Twitter at @KaineK, and read his blog at

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