Insects Found While Crossing Lake Michigan

2015 September 5

Earlier this year (2015), Sam had said that she wanted to see what it was like to travel on a “real ship”. So when we took a trip downstate on July 23, we went down to Manitowoc, Wisconsin so that we could cross Lake Michigan[1] on the SS Badger[2], the last remaining coal-powered passenger ship operating on the Great Lakes.

While we were waiting for our car to load in Manitowoc, Sam spotted this little fly with patterned wings on a picnic table.

From the striping pattern on the wings, and the general body shape, I think it is a Signal Fly, in the genus Rivellia.

They are supposed to be difficult to identify to species just from appearance, but the most common species in the Midwest is Rivellia quadrifasciata, also known as the Soybean Nodule Fly. It seems the maggots live underground and feed on the nitrogen-fixing root nodules[3] of certain legumes, including soybeans. This evidently doesn’t cause much noticeable harm to the plants, probably because all it does is reduce their supply of fixed nitrogen.

Later, once we were on the ship and underway, Sandy found this iridescent beetle crawling around the deck. The pictures aren’t too good, but it appears to be some sort of Carabid beetle.

For some reason, I’m having difficulty finding pictures of metallic beetles with purple backs and green margins. The closest I see are some of the Colorful Foliage Beetles in the genus Lebia, although none of the ones up on BugGuide are a perfect match. Of course, matching a blurry picture is going to be difficult in any case, so I think I’ll just leave it at that.

Anyway, after about five hours cruising on a beautiful, clear day, we got to Ludington on the Michigan side, where we saw the Badger’s sister ship, the Spartan, laid up at the dock.

Sam was surprised that it was just sitting there, rather than being either taken somewhere else to use, or cut up for scrap. Evidently, the owners of the Badger still think that they may have some use for a second ship at some point[4].

Anyway, Ludington has nice, sandy beaches, as it is right in the middle of the eastern shore of Lake Michigan, which is all white-sand dunes as far as the eye can see[5].

And on this beach, we found what at first I thought was a net-winged beetle, but on closer examination turned out to be a milkweed bug.

The giveaway that it was a true bug, and not a beetle, was the long piercing-sucking proboscis.

It had been beaten around by the waves, which was why its wings were partially open. Normally, it would have had its wings more neatly tucked together, which would have made it more obvious that it was the Large Milkweed Bug, Oncopeltus fasciatus. It has the standard black-and-red coloration of insects that feed on milkweed and accumulate the plant toxins into their own bodies, making themselves inedible. These specifically feed on the flower heads and seeds of milkweeds, rather than on the plant proper, so even though they are often seen on milkweed along with the monarch butterflies, they aren’t really competing for the same parts of the plant.

[1] Normally, when we drive to the Lower Peninsula of Michigan, we go across the Mackinac Bridge. But we’ve been across that bridge so many times over the years that a change seemed to be in order. Granted, for where we are starting from and going to the ferry is no faster, and costs more, but at least it goes somewhere different.

[2] There used to be a lot of ferries shuttling across between Ludington and various cities in Wisconsin. They mainly hauled trains across so that they could avoid having to go all the way down to the end of the lake and through the congested mess that is Chicago. But, with the Interstate highway system and trucking eliminating a lot of rail traffic, business fell off. Now the Badger only shuttles vehicles and certain kinds of cargo, and is mainly a tourist thing rather than a major part of the transportation system. It does seem to do good business, though. You need to make a reservation some days in advance for a slot, and when we went across it was packed full, to the point where getting the last few cars on looked a bit like playing Tetris.

[3] Legumes like beans and clover and locust and the like are known as nitrogen-fixing crops, using their root nodules to convert atmospheric nitrogen (which isn’t a useful nitrogen source for most living things) into ammonium and nitrates (which are chemically reactive enough to be useful). However, the plant itself isn’t doing the job. All it is doing is providing a home for the bacteria that actually carry out the “nitrogen fixation” process. This is a typical sort of thing that is done by multicelluar organisms when they need some sophisticated chemistry done: rather than evolve the ability to do it themselves from scratch, they recruit appropriate bacteria that have already evolved the ability, and strike up a symbiotic relationship.

[4] In the distance beyond the Spartan, you can see quite a number of wind turbines. The wind turbines are there partly because it is a pretty windy place, and partly because the Ludington Pumped Storage Power Plant is right there. The whole idea of the facility is that when the demand for electricity is low it can use the excess generating capacity to pump water uphill from the lake, and then when the electric demand goes above baseline it can let the water run back downhill again to regenerate power and send it back into the grid. So it is basically a gigantic electrical storage battery. This is was originally built in the early 70s as a load-levelling device for the power grid, because Consumers Energy and Detroit Edison operate nuclear power plants. Nuclear plants are basically base-load generators, that are slow to respond to load changes and work best when they are constantly running at their design capacity. Without the pumped storage plant, the power company would have to have natural-gas-fired generators on hand that could be turned on and off quickly to respond to the higher and rapidly changing electrical demand during the day, and then have the nuclear plants running under capacity at night. So, by storing the excess energy generated overnight, they can avoid the need for having the natural-gas-fired generators. But, the pumped storage also works great as a storage battery for intermittent power sources like wind turbines and solar panels, which rarely generate their power at the exact time you need it. So if one is going to put in wind turbines anywhere, Ludington is one of the best places to put them.

[5] The Lake Michigan beaches are quite a bit different from what we are used to. For example, here is a fairly typical day on a typical Lake Superior beach[6], only about 15 miles from our house:

[6] OK, OK, I was kidding a bit with that last picture (which was taken in November). (Only a bit, though. The lake really is that cold, or worse, from about the middle of October until almost the middle of June). There are some sandy beaches, and occasional nice summer days, on Lake Superior. Like this one, from the middle of July over at a beach on the east coast of the Keeweenaw Peninsula:

Although, you may note that there are more people standing on the shore viewing the water with deep suspicion, than there are people actually in the water.[7] That’s because, even in July, the water is cold – the surface water temperature rarely passes 50 degrees F, and hypothermia is always an issue for swimmers no matter how high the air temperature gets.

[7] Rosie (in the blue swimsuit) is the exception. She’s a good candidate for the Polar Bear Club. She is almost completely unconcerned about cold most of the time.

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