Hello!
If you found a trap like this out in the JKS Wilderness and you're here, then you're curious about my project. Well, as promised, here's some more info!
I am a PhD student working on an invasive fruit fly called the spotted wing drosophila (aka SWD). It's a huge problem for fruit growers around the world, and here in NC it especially affects blackberries, strawberries and blueberries that we grow in large quantities. You can learn more about the fly here. A lot of work has been done in and around farms, where the fly causes economic damage to the farmer (in essence, an infested berry is one that can't be sold, meaning lost profits). What we don't know much about is whether the fly is elsewhere in the landscape, and what kind of impact it could be having there.
So beginning in 2017, I've been surveying the JKS Wilderness area and looking for SWD. And I found the fly... a lot of flies! Wild growing blackberries (Rubus canadensis) is a common invasive plant found along roadsides and in the woods. Their seeds are dispersed by birds and it's great at colonizing disturbed areas, so it's one of the first plants to appear after forest fires (like the ones in 2016).
This year, I'm looking to collect wild blackberry fruit to help estimate how many flies unmanaged areas like this are producing. The traps help with that, as they are used as a monitoring tool to look at relative population size between different areas. I also have some in cultivated blackberry fields. The yellow pouch inside emits a smell that attracts SWD. Once they enter the trap, the water and dish soap solution at the bottom drowns them. I collect the flies every 7-10 days and count how many flies it caught. Then I can compare those numbers to other trap catches.
I appreciate your interest, and your respect for leaving the traps alone. I will be done with this project by the end of September at the latest, after which all the traps will be gone. If you have any more questions, email me using the contact page on this site, or the email I provided on the trap. Happy hiking! -Johanna
P.S. This is me. Say 'hi!' if you see me hiking about :)