Orange-legged drone fly (Eristalis flavipes)
This week we’ll meet a fab, fuzzy fly who’s worth taking a close look at. Meet the orange-legged drone fly (Eristalis flavipes).
It’s quite likely you’ve seen an orange-legged flying around your garden but gave them their personal space because they do a masterful job of mimicking bumblebees.
Orange-leggeds are so adept at mimicking bumbles, they even come in different color forms to mimic different bumble species. Some are black and yellow only, while some have a red band on their abdomen to mimic tri-color bumblebees. They are also bumble-sized (one-half of an inch) and imitate bumblebees’ flight patterns.
Basically orange-leggeds get the bumble benefit of being left alone while being totally harmless.
There are three quick ways to tell if the fuzzy flitter on your garden flowers is a bumble or an orange-legged: Orange-legged have big old compound fly eyes at the front/top of their heads. Bumbles have smaller eyes on the sides of their heads. Pictured is a female orange-legged and as drone flies go her eyes are considered “small.” Male orange-leggeds and their other drone fly cousins have holoptic eyes, which you may recall means the eyes are so large they meet in the top middle of the insects’ head.
The second way to discern an orange-legged from a bumblebee is their antennae. Oranges have short antenna that “sprout” from the center of the fly’s forehead and touch at the base. They also have only one evident segment. Bumblebees’ antennae have a visible space between their bases, are much longer and have a joint in the center.
Lastly orange-leggeds and bumblebees make very different sounds when flying. Bumblebees have four wings (left and right forewings and hindwings) which make a louder buzzing sound in flight. Oranges – like all flies – have only two wings, which make a softer humming sound. Because oranges are so large, they do make a louder sound than most flies, but not as loud as a bumble.
Fun fact: Orange-legged drone flies are in the Genus Eristalis. There are 20 North American species in this genus and all are bee mimics. However, the other 19 species mimic honeybees; only orange-leggeds get to cosplay as bumbles.
When it comes to being a beneficial insect, orange-leggeds have six legs up on bumblebees because they bring benefits in both their juvenile (larval) and adult forms.
Now we must confess that larval drone flies have one of the more unfortunate common names around. They are called “rat-tailed maggots.” Apologies if you were having a snack while reading that.
The name isn’t off-base though, as the baby drones do look like they have rat-like tails. They use these not-tail “tails” as snorkels because they live in eutrophic waters. Those are waters that are rich in plants and decaying matter, but low on oxygen, thus the need for snorkels.
For all their not-so-good looks and icky name, baby drone flies give back to their environment by filter feeding, cleaning as they go.
As for the adults, as you can tell from one of the photos, orange-leggeds live on a steady diet of pollen and nectar. With their fuzzy bodies, they pick up and pass along a lot of that pollen as they go.
Orange-leggeds are not picky about which flowers they visit, and they are on the wing from April through October so they’ll pollinate everything from your Easter lilies to your fall vegetable harvest.