Presenting: Awbury’s 2018 series on pollinators– from wasps to wind!
Monthly articles will correspond with our programming and our “Pollinators FOUND at Awbury Arboretum” art show and scavenger hunt.
Articles written by La Salle student and Awbury intern Dan Sardaro.
OCTOBER 2018 – HOVERFLY
Suddenly, a microscopic insect flits your way while you’re peacefully enjoying your backyard garden. It’s black and yellow, has wings, and that combination just can’t be good. It keeps its distance and hovers around you for some time, like it’s waiting to strike. Is it a bee? A wasp? Some new species of tiny killer bug?
Nope. Probably none of the above. It’s tough sometimes to think straight when we encounter what we think is a stinging insect, since often we are hard-wired to think that all black and yellow flying insects are dangerous. One such example that may confuse us is the hoverfly, a small flying critter belonging to the family Syrphidae that poses no harm to us humans because it doesn’t sting. In fact, this little pollinator helps us more than we know. Karen Singer’s tilework this month shows the tiny two-winged creature on chrysanthemum.
In the 19th century, when naturalist Henry Walter Bates was studying butterflies in the Amazon, he first described the phenomenon of harmless species mimicking dangerous ones, a strategy that effectively dissuaded predators from trying to snag a meal. Similar to our friend the eastern tiger swallowtail caterpillar who uses an intimidating pair of false eyes on its head, the hoverfly elicits fear in an oncoming predator by making them think that they can inflict a painful sting. As we now know, it’s all a trick. There’s a saying that goes: “Two wings fun; four wings run.” I won’t say that you should run from an insect with four wings – bees won’t sting unless provoked. But, you can count on an insect with two wings like our little hoverfly being friendly.
Hoverflies pollinate a variety of ecosystems worldwide, but they also play a large role in our backyard gardens. But another superpower they have in our backyards and farms is their biological control of aphids in crops like lettuce and grains where these pests love to gorge. The hoverfly’s appetite for these leaf-eaters keeps gardens and crops healthy and productive, since hoverfly larvae will eat on average 400 aphids before maturing into an adult fly. Parent flies will even pinpoint aphid colonies in the middle of fields and lay eggs nearby, ensuring that it’s young will have access to food. In recent years, much research has been directed at ways of propagating hoverfly populations near crops to keep yields abundant.
My advice for your garden? Don’t be afraid of a few pests. Spotting aphids on leaves won’t necessarily harken ill-fated news for your plants. So don’t go nuts – a few pests means that the species that eat them will have adequate food sources, keeping natural predation cycles fluid and pollination abundant.
Frank, Steven. “Hoverflies – Bee Mimics Provide Pollination and Biocontrol Services.” NC State Extension News, NC State University, 11 Jan. 2016, entomology.ces.ncsu.edu/2015/06/hoverflies-bee-mimics-provide-pollination-and-biocontrol-services/.
Mason, Sandra. “The Homeowners Column.” Wildlife Directory: Eastern Cottontail Living with Wildlife University of Illinois Extension, University of Illinois, web.extension.illinois.edu/cfiv/homeowners/140926.html.