Last year Steve Stewart of Michigan State University Extension shared The Mayflies are coming – time to celebrate!:
It’s summer, so it’s time for the mayfly hatch! There are hundreds of species of mayflies (also commonly referred to as fish flies) in North America, representing a number of Families in the Order Ephemeroptera. Ephemeroptera comes from the Greek word for “short-lived” (as in “ephemeral”), and it’s a good name because as winged adults, mayflies only live a few days. The most widespread burrowing mayfly species in the Great Lakes is Hexagenia limbata, the Giant Mayfly.
Mayflies have a very interesting life cycle. They are the only insect to have two “adult” molts, and begin life as eggs laid on the surface of the water that sink to the bottom. The aquatic nymphs of mayflies are called naiads, and creep around rocks and vegetation. After months or years (depending on the species), they float to the surface and molt to a winged, but sexually immature, sub-adult. Often within hours, another molt occurs and the final stage emerges—the winged, reproductive adults, which possess only vestigial mouth parts and cannot eat or drink and, depending on the species, live for only days or, in some cases, mere hours.
One of the most obvious characteristics of the adults is their large numbers. They can emerge in huge numbers from a body of water. So huge, in fact, that their swarms can be seen on Doppler radar! This image is from June 14 showing a mayfly swarm over western Lake Erie, pushed ashore in Monroe County by an easterly breeze. Once ashore, mayflies tend to sit on upright objects and can completely cover the surfaces of posts, sheds, and light poles. At night, they are attracted to lights.
Some people think of mayfly hatches as a nuisance, and they can be a bit annoying when they are swarming. But mayflies are a good thing. Some people think of mayfly hatches as a nuisance, and they can be a bit annoying when they are swarming. But mayflies are a good thing. They are rarely found in degraded bodies of water because their external gills in the nymph stage are very vulnerable to silting and pollution. Mayflies are, therefore, used as an indicator species when testing for environmental quality, and their presence reflects the good quality of the habitat from which they hatched.
Read on for more including photos and school lessons on the Mayfly.
Garret Ellison of the Grand Rapids Press & mLive writes that the Michigan Department of Natural Resources expects spruce budworm to inflict heavy damage on white spruce and balsam fir trees across the Upper and northern Lower Peninsulas this year:
The budworm is “one of the most destructive native insects” in the northern spruce and fir forests of the eastern U.S. and Canada. The worms drop as caterpillars from treetops on webs and feed on tree growth in the spring.
Repeated budworm defoliation can cause top-kill and death in older and stressed trees. Balsam fir older than 60 and spruce over 70 years are prime targets. Younger trees infested with budworms lose much new growth but generally survive.
The spruce budworm Choristoneura fumiferana (Clemens) is one of the most destructive native insects in the northern spruce and fir forests of the Eastern United States and Canada. Periodic outbreaks of the spruce budworm are a part of the natural cycle of events associated with the maturing of balsam fir.
The first recorded outbreak of the spruce budworm in the United States occurred in Maine about 1807. Another outbreak followed in 1878. Since 1909 there have been waves of budworm out breaks throughout the Eastern United States and Canada. The States most often affected are Maine, New Hampshire, New York, Michigan, Minnesota, and Wisconsin. These outbreaks have resulted in the loss of millions of cords of spruce and fir.
Balsam fir is the species most severely damaged by the bud-worm in the Eastern United States. White, red, and black spruce are suitable host trees and some feeding may occur on tamarack, pine, and hemlock. Spruce mixed with balsam fir is more likely to suffer budworm damage than spruce in pure stands.
If you’re intrigued by the “natural cycle” as I was, head over to Wikipedia’s entry on Choristoneura fumiferana, the Eastern Spruce Budworm for an explanation and some pics of these (for a change) native pests.
PS: Sorry about the Monday morning novel … sometimes I over share. ;)
Yesterday Michigan in Pictures regular Mark O’Brien shared Nature’s Drone, Pretty and Deadly. The article says that although lions (25% hunting success rate) and great white sharks (50% success) look deadly, the dainty dragonfly may be the most effective hunter in the animal kingdom:
When setting off to feed on other flying insects, dragonflies manage to snatch their targets in midair more than 95 percent of the time, often wolfishly consuming the fresh meat on the spur without bothering to alight. “They’ll tear up the prey and mash it into a glob, munch, munch, munch,” said Michael L. May, an emeritus professor of entomology at Rutgers. “It almost looks like a wad of snuff in the mouth before they swallow it.”
Next step: grab more food. Dragonflies may be bantam, but their appetite is bottomless. Stacey Combes, who studies the biomechanics of dragonfly flight at Harvard, once watched a laboratory dragonfly eat 30 flies in a row. “It would have happily kept eating,” she said, “if there had been more food available.”
In a string of recent papers, scientists have pinpointed key features of the dragonfly’s brain, eyes and wings that allow it to hunt so unerringly. One research team has determined that the nervous system of a dragonfly displays an almost human capacity for selective attention, able to focus on a single prey as it flies amid a cloud of similarly fluttering insects, just as a guest at a party can attend to a friend’s words while ignoring the background chatter.
Read on for more including some very cool videos of dragonflies in action.
More science on Michigan in Pictures!