Student Alex Bruce photographs a football-sized bald faced hornet nest that hangs from a pear tree. (Photos by Linda Weiford, WSU News)
PULLMAN, Wash. – No insect drew more gasps than the parasitoid wasp during a field trip of undergraduate entomology students at Washington State University’s organic farm. But it wasn’t the wasp’s sting that made some step away with their eyes wide. It was the insect’s bizarre attack on an aphid on the underside of a just-picked kale leaf.
|WSU organic farm manager Brad Jaeckel.
Reminiscent of a famous scene in the 1979 horror film, “Alien,” when a baby space creature bursts out of a human’s gut, wasp larvae that had hatched inside the aphid were busting their way out.
“Believe it or not, parasitoid wasps are not the bad guys here,” explained organic farm manager Brad Jaeckel to the group. “This is an example of good bugs destroying bad bugs.”
The tiny wasps – only an eighth of an inch long – are weapons in the natural arsenal that attack plant-eating bugs, said Jaeckel.
“It’s because of insects like these that we don’t have to use pesticides and other synthetic chemicals,” he said.
In right foreground, entomology Ph.D. students Robert Zinna, left,
and Elias Bloom show students insects caught during a “sweep”
of a crop row at WSU’s organic farm.
And so it was on this September afternoon that Jaeckel led 20 students from WSU’s “Insects, Science and World Culture” class around the four-acre farm on the rim of campus. The class, taught by entomology Ph.D. student Robert Zinna, does more than give students a leg or six up on science.
“By examining how insects impact civilizations, art, what we eat and what we wear, my hope is that it diminishes the ‘ick factor’ associated with insects,” Zinna said. “In this country, there’s a tendency to view all bugs as bad. And they’re not. Far from it.”
Ink and dyes, beeswax in candles, crickets ground into flour, honey on our toast, silk threads in our scarves – all are examples of how we benefit from bugs, he said. But we also harness them for their work among crops and flowers, and that’s what Zinna wanted his students to see at the organic farm.
“Rather than say to students, ‘This is a bug; you should like it,’ I take them on field trips so they can actually witness the beneficial things bugs do,” he said.
Sophomore Sierra Dwyer is one of those students, albeit reluctantly.
“I don’t like bugs at all. My hope is that by learning about them, I can get over my fear,” she said. “Just maybe, I’ll come to admire them.”
Natural born killers
At the organic farm there was plenty to admire, including the parasitoid wasps, teeny enough to miss if not for the trained eyes of Zinna and Jaeckel. Despite the wasps’ horror-movie-like way of chewing their way out of aphid innards, “they do a great job of pest control,” Zinna told the group while holding up a kale leaf dotted with several mummified aphids.
Bumblebees, lacewings and ladybug beetles (technically, ladybugs aren’t bugs; they’re beetles) are also important natural enemies of pests, he explained.
Lacewings, with their slender green bodies donning transparent green wings, could be seen flitting from plant to plant. While adult insects feed primarily on nectar and pollen, their larvae devour aphids, Zinna told students.
An earwig. Don’t believe stories
that they climb into people’s ears
while they sleep, said Zinna.
When one student pointed out an earwig nestled in the hollow of a plant leaf, the group’s – ahem – ears perked.
“Contrary to what you may have heard, earwigs do NOT crawl into people’s ears when they’re sleeping and lay eggs on the brain. That’s one of many myths about insects,” explained Zinna, who then steered students toward a row of brilliant sunflowers.
The towering flowers weren’t planted there for their beauty, he said. Instead, they are part of the farm’s natural pest management strategy, both blocking weeds and acting as giant landing pads to draw beneficial insects that pollinate.
Alex Boyce, a senior majoring in history, said he better understands the clever methods organic farmers must use to grow crops without chemicals.
“My girlfriend and I try to eat organic. I had no idea of the positive interplay that goes on between the insects and the food being grown,” he said. “I certainly appreciate bugs more, but that doesn’t mean I’d eat them for breakfast.”