Today’s chapter in the Sound Ideas winter series is a recording from the evening of September 4 last year. I made it in the Miller Woods portion of the Indiana Dunes National Lakeshore. Three very different singing insects can be heard distinctly throughout:
The principal target of this recording produced the annoying, continuous buzzing sound. If you had been there, you would have remarked at how loud this insect was. It was a robust conehead.
Male robust conehead, singing posture
This katydid has a sibling species, creatively named the false robust conehead (Neoconocephalus bivocatus). I haven’t documented bivocatus in the Chicago region, but there are a couple old possible records, so occasionally I record an individual and check the pulse rate and pattern. So far, all have been good old Neoconocephalus robustus.
The other two members of that night’s trio both produced regular, brief chirps: one higher pitched and very regular in its rhythm, the other much lower and a little less regular. The higher pitched singer is famous for the way its chirping rate varies with temperature: count the chirps in 13 seconds, and add 40 to get the degrees Fahrenheit. We know this singer as the snowy tree cricket.
Snowy tree cricket male, taking a break from singing to snack on skin.
That leaves the bass section. The lower pitched continuo is the product of a northern mole cricket. This swale area of Miller Woods is one of only 3 locations where I have found this species to date. I don’t have a photo to show you. True to his name, the mole cricket sings from within his tunnel, and I haven’t yet had a photo op with the critter.
Ah, yes. I see an insistent hand upraised in the back of the class. Yes? Ah, very good. Yes, there is a fourth, more intermittent performer here. Those few added chirps are a fall field cricket’s, practically ubiquitous at this point in the season, and determined to insert himself into any ensemble.
A continuing theme in my regional survey of singing insects is the paucity of wetland species. The only one that is present in good numbers in many wetlands is the black-legged meadow katydid. Other species common in wetlands are habitat generalists such as the Carolina ground cricket and short-winged meadow katydid, which don’t truly count as wetland insects. One clear cause of this problem is the loss of high quality habitat to four invasive plant species (purple loosestrife, reed canary grass, common reed, and cattails). All four are capable of completely taking over a wetland, and examples of this can be found for all four. Small numbers of the singing insects mentioned above can be found in such places, but not the other wetland insect species.
This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.
On the other hand, there are some good wetlands out there. Many are small, and this along with their isolation may limit them.
This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.
Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.
This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.
Still, I have not given up hope. I found a third good population of mole crickets this year, in a swale at Miller Woods.
Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.
I also found melodious ground crickets at two new sites in Berrien County, Michigan. Though I did not find dusky-faced or delicate meadow katydids at the Indiana Dunes’ Great Marsh this year, I felt curiously encouraged by this.
Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.
Maybe the populations of many wetland species took a hit in last year’s drought, and were thinly dispersed in the expanded wet areas of 2013. This is, after all, the first year in which I have surveyed many of these sites. If they need a couple years to recover from the drought, maybe I will find the missing species in the future. Still, how to account for the lack of nimble meadow katydids? This species I have yet to find, anywhere. In the heart of the singing insect season I took my sea kayak into an area where they historically were known.
The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.
Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.
So the bottom line is a disappointing season for wetland species, with a few positive points and hope in the possibility that populations are at a low point from which they will recover.
It has been a memorable few weeks. This year I took the bulk of my vacation time in the heart of the singing insect season, mid-August to mid-September, and spent most of it traveling around the 22-county area, from southwest Michigan to southeast Wisconsin, where I am seeking the 100 species of cicadas, crickets, katydids and singing grasshoppers that occur (at least potentially) there. This travel took me to many memorable places.
High quality forests are scattered around the region. Sanders Park, Racine County, Wisconsin.
I didn’t spend a lot of time in the forests, however, much as I love them. Most singing insects live in more open habitats.
The dunes around the edge of Lake Michigan provided some of the most open habitats. Warren Dunes State Park, Michigan.
One of my favorite areas was Miller Woods at the western end of the Indiana Dunes National Lakeshore.
The trail leads through savanna and past wetlands. Here it crosses a former rail foundation.
The Miller Woods Trail eventually skirts a large pond at the edge of the dunes, and reaches the beach.
Wetlands included Bluff Creek in the Kettle Moraine State Forest, Walworth County, Wisconsin.
The water was beautiful and clear, flowing over stones and gravel.
A fen-like wetland, bordering the creek, contained species such as the fringed gentian.
Sure, I was paying attention to species other than singing insects. At the Houghton Lake Nature Conservancy property in Marshall County, Indiana, I encountered a couple interesting ones.
A Chinese mantis nymph stalked through the wetland vegetation.
This gray treefrog snoozed in a leaf bed.
The most extensive prairie I encountered was in the Bong Recreation Area, Kenosha County, Wisconsin.
Its size alone speaks to the potential in this restoration project.
For now I will close with the sunset on my last evening at Bong.
The sunset was a beautiful prelude to a rainy evening in camp.
The singing insects of course were the focus of all this travel. I’ll share images of some of them in future posts.