For enthusiasts who require fruit flies for various purposes, such as creating cultures for feeding small reptiles or studying insect behavior, obtaining specific species and sizes can sometimes be challenging. While purchasing fruit flies online is an option, particularly for guaranteed species like Drosophila melanogaster, finding winged varieties for flight-capable cultures can be surprisingly difficult. Observing the local wild fruit flies often reveals the perfect specimens, but capturing them efficiently becomes the primary hurdle. Fortunately, attracting and catching wild fruit flies is a straightforward process that anyone can accomplish with a few simple steps. This guide will walk you through an easy and effective method to attract and capture these tiny insects right in your own backyard.
Step-by-Step to Lure and Trap Fruit Flies
This method leverages the powerful attraction of fermentation to draw fruit flies in, making capture simple and efficient. Here’s how to do it:
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Prepare an Irresistible Bait: Start by placing a piece of fermented fruit, such as mango peel, into a deli cup. Fermented fruit is exceptionally effective at attracting fruit flies due to the strong odors it emits, which are highly enticing to these insects. If fermented fruit isn’t available, you can substitute it with your regular fruit fly culture medium mixed with a teaspoon of apple cider vinegar. Apple cider vinegar mimics the appealing scent of fermentation and works effectively as an attractant.
Alt text: Close-up of a deli cup containing fermented mango peel, effectively attracting several fruit flies around the rim and inside, demonstrating a simple bait trap.
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Construct a Selective Trap Lid: Next, create a lid for your deli cup using an aluminum wire screen. This screen lid is crucial because the small openings are designed to be just large enough for fruit flies to enter while preventing larger insects, like houseflies or wasps, from getting in. If you find that the fruit flies in your area are larger than average and are struggling to enter, you can easily enlarge the holes in the screen. Use a sharpened pencil or a similar pointed object to carefully widen a few openings, ensuring they are appropriately sized for your local fruit flies.
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Set the Trap and Wait for the Catch: Place the baited deli cup, now covered with the screen lid, outdoors in a sheltered location where it won’t be disturbed. A spot in the shade or under a bush works well. Leave the trap for a couple of days. During this time, the scent of the bait will attract fruit flies from the surrounding area. You’ll know it’s working when you observe a noticeable gathering of fruit flies around the cup and potentially see maggots (fruit fly larvae) beginning to appear in the medium.
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Secure and Transfer Your Captures: Once you’ve attracted a significant number of fruit flies, and ideally see larvae indicating successful egg-laying, it’s time to secure your catch. Quickly cover the screen lid with a piece of saran wrap to trap the flies inside the cup. To make handling easier, place the entire cup in the refrigerator for a brief period, about one to two minutes. This chilling will temporarily immobilize the fruit flies, making them easier to manage. Be very careful not to leave them in the fridge for too long as over-chilling can be fatal.
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Establish Your Fruit Fly Culture: Working swiftly while the flies are still inactive, remove the screen lid and take out the mango peel, carefully scraping off any maggots you see back into the culture medium. Immediately add some excelsior (or a similar climbing medium like shredded paper or coffee filter) into the cup. Excelsior provides a surface for the flies to climb on, preventing them from getting stuck in the culture medium and also increases the surface area for pupation. Quickly seal the cup with a new breathable lid, such as a fabric lid, which allows for air exchange while preventing escape. Now, let the flies warm up and awaken in their new home.
Cultivating Your Wild Fruit Fly Culture
From this point, your fruit fly culture should flourish. You can easily start subsequent cultures by transferring a portion of the media and some flies from your initial culture to a new setup. This simple method is incredibly cost-effective, essentially free if you reuse deli cups and make your own culture medium. The minimal cost primarily involves the cup and culture medium ingredients, making it an accessible and rewarding way to obtain fruit flies for any need.
