If you came out last fall, you probably saw swarms of little white insects resembling the villain in an old sepia-toned horror movie called “The Carnivorous Swarm” or something so ridiculous. However, for those who know Moscow, they signal the arrival of autumn.
These bugs are aphids of the dark-winged ash (Prociphilus Americanus). Also known as the conifer root aphid, it is a species of aphid known to jump between two hosts, a summer host and a winter host.
Sanford Eigenbrode, professor of entomology here at the University of Idaho, studies parasites such as these aphids for a living.
“More than half of aphid species are homocyclic,” Eigenbrode said. “They have summer hosts and winter hosts that they see every year…. These guys have two trees that they use. They use fir trees in the summer, and if you dig into the roots of the trees, you would find them, and they overwinter on the ash trees.
This migration from their summer homes among the fir trees to their winter homes within the ash trees is exactly why we see them every fall. During this migration, aphids acquire a waxy coat that allows them to escape the sticky sap in which they nest. This wax also makes them appear larger than usual, making them more visible to the naked eye.
“They get to the ash trees where they lay eggs and the eggs hatch in the winter and feed on the ash, then they can go back to the firs,” Eigenbrode said. “We don’t see them coming back [to the firs] but we see them come in almost every year.
These guys aren’t as innocent as they might seem, either. While they don’t deal significant damage to UI ash trees, they do much more harm to the trees they spend the summer on.
“Fir trees are a very important species for Christmas trees, and these types can become pests for growing Christmas trees,” Eigenbrode said. “They prevent trees from growing fast enough to reach market size.”
However, Christmas tree farms aren’t the only place where small insects seem to be a nuisance. They seem to cover university windows, streets and even people’s hair.
Another article by Argonaut in 2015 qualified these air pollution as “societal nuisances”.
Sydney Schoth, a bioengineering student on campus, has already swallowed one, much to her chagrin.
“I accidentally inhaled it.” said Schoth. “I gagged on myself, and it tasted salty.”
Other people got stuck in their hair and even in their eyelashes, leading more than one to find a horrible dead bug in a place it shouldn’t be.
However, as we move fully into winter, they seem to be receding.
“I was just talking to a graduate student who had an earth on his hand a few days ago,” Eigenbrode said, “But the main swarm is mostly over. However, for students who will be returning to campus next fall , be on the lookout, they will become an old friend.
Abigail Spencer can be reached at [email protected]