The Hover Fly: A Sheep in Wolf’s Clothing
by Ellen Rathbone
There you are, enjoying a pleasant stroll among the flowers, when your eyes suddenly land on a black and yellow banded insect getting a meal on a flower. “A bee!” your mind screams, and you hastily blunder your way out of the garden in full panic mode. When you reach the safety of the house, you contemplate grabbing a can of Raid and eliminating the unwanted insect. If, however, you had taken the time to look at the insect, you might have noticed two things. One, the “bee” only had two wings (most insects have four; flies have two), and two, the body was not fuzzy. This is no bee. It is a beneficial insect called a Syrphid, or Hover, Fly.
Syrphids are nifty, harmless flies. Although they may look like a bee or yellowjacket, they have no stingers. Their cryptic coloration fooled you, though, as it was supposed to. By looking like a bee or wasp, this insect is able to trick predators that might otherwise want to make it a meal.
Like our friend the housefly, Syrphids are equipped with sponge-like mouthparts, which they use to mop up meals of pollen and nectar. As such, they are very important pollinators, flying from blossom to blossom and transferring pollen as they go. But the benefits of these boldly colored insects don’t end here. Their larvae are also important.
The larvae of some species of Syrphids feed on decaying vegetation and fungi, making them important cogs in nature’s recycling system. Others seek out the nests of ants, termites and bees. But the ones that are dear to the naturalist’s (and gardener’s) heart are the ones that seek out and destroy aphids. In these species, the female adults lay their eggs singly near a herd of aphids. In days the egg hatches and the legless, slug-like larva oozes its way towards its prey. When an aphid is encountered, the larva raises its head, clamps onto the juicy body, and sucks it dry. Over the course of its short life, the larva can consume upwards of 400 aphids (provided their ant protectors don’t evict it first), providing relief to the host plant the aphids were draining.
The next time you find yourself walking through a field of flowers, along a roadside, or in your garden, keep your eyes peeled for these bright, bi-winged insects as they hover over the blossoms. Take a few moments to observe their behavior. You never know what else you might discover.
6 Comments:
That is so cool I didn't know anything about syrphid flies and now I do. Thanks for the lesson.
As a rule, I don't exterminate bees anyway... Good post though! Still, knowing what I know now probably won't stop me from screaming bloody murder next time one of these buzzes my head...
A perfect essay. Thanks.
I have a question for Ellen! I could look it up on Wikipedia, but that's boring... I've been turning out all of the lights outside of my house lately (during the night) to watch the swarm of fireflies that descends on the property when the sun goes down... I've lived in the ADKs all of my life, and I can't recall every seeing so many! So I have two questions I guess:
1.) Why am I seeing so many this summer, when in past years even seeing one was a treat?
2.) What makes them light up?
Thanks!
Y'know, Chris, I've been seeing a lot more fireflies this year, too! I don't have an answer as to why, however. I can tell you that in many places, mostly urban and especially in the south, firefly populations are decreasing and some studies suggest that those solar lights people put out along walkways and gardens are the culprits. These lights add to the already bright night sky, but they are now lighting up the few dark spots in lawns. The fireflies are apparently having diffculty, in all the light, seeing their own lights, and therefore they are not mating. No mating, no new fireflies.
As to what makes them light up, that is an easy answer! Magic. Just kidding. It's bioluminescence, a cold light that results from a chemical reaction inside the firefly's body. When the chemicals mix, they create energy in the form of light, with very little heat given off (man has yet to create such highly efficient lighting). There are four chemicals used in the process: oxygen, ATP (adenosine triphosphate, a chemical found in all living things and the one that controls how bright the firefly's light is), luciferin and luciferase (these last two are made by the firefly). If you look at the underside of a firely, you will see its light organs on its abdomen, near the tail. The chemical reaction takes place within these organs as the firefly brings in oxygen through small holes in the abdomen.
Like I said: magic! :)
Nice! Thanks for the post Ellen! I actually had a firefly walking up a screen the other night, and I got to look at its underbelly up close.. Very cool!
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