Return to Cicadas

by Carl Strang

On Monday I returned to the area where I searched for northernmost lyric cicadas, as described two posts ago. I had thought I heard a swamp cicada at Penny Road Pond, and wanted to listen again to confirm it.

Swamp cicada

Swamp cicada

This time two were singing, and there was no doubt I was hearing swamp cicadas’ percussive vibrato. The observation represented a shift well to the north of my previous northernmost location for the species.

The red star indicates the previous location at West Branch Forest Preserve in DuPage County. Penny Road Pond is marked by the yellow star. The two places are around 12 miles apart.

The red star indicates the previous location at West Branch Forest Preserve in DuPage County. Penny Road Pond is marked by the yellow star. The two places are around 12 miles apart.

I don’t know of any place in my 22-county survey region that has abundant swamp cicadas. As the map shows, I haven’t documented them in many counties. In large part that is because they sing only in the morning, and I have done most survey work in the afternoons and evenings when the majority of singing insects are displaying. On the other hand, I went for many long morning bicycle rides in Starke and Marshall Counties, Indiana, and heard only widely scattered individuals. Such a thin spread prevents me from being confident about finding the swamp cicada’s range boundary in the Chicago region.

Back to Monday of this week. I wanted to employ the bicycle as a tool again, this time to see if I could extend the lyric cicada’s northernmost point beyond last week’s record. I started from Trout Park, where I had heard that individual, and dropped down onto a bike trail that took me north along the Fox River. After going 6 miles without hearing a lyric cicada I turned around and headed back. Shortly after making that turn I heard a single lyric cicada, though, giving me a new north point 5 miles beyond the one reported earlier. That was it, however, as I heard no more on the return ride.

Revised lyric cicada map. The new location brings that species’ known range within 2 miles of the McHenry County border.

Revised lyric cicada map. The new location brings that species’ known range within 2 miles of the McHenry County border.

That is as much as I will do this year to determine the possible northward expansion of these two cicadas. I will be interested in pursuing this study in the future, mindful that the thin scatter of both species will lend some uncertainty to the results.

Advertisements

New North for Lyric Cicadas

by Carl Strang

Last week I took a morning to see if I could extend the northernmost known locations for the lyric cicada. Its song is easy to recognize, but at the north edge of the range they are few, and finding them takes time.

Lyric cicada

Lyric cicada

Last year the northernmost ones in Cook and Kane County were at the Carl R. Hansen Woods and Tekakwitha Woods Forest Preserves, respectively. This year I found them several miles farther north in each county. In Cook County the new north was at the entrance to the Crabtree Nature Center, 6 miles beyond the previous record and now only 5 miles south of the Lake County border.

Chicago region range map for the lyric cicada. Black dots indicate counties where the species occurs. Red stars indicate northernmost locations known through 2014. Yellow stars indicate northernmost locations found in 2015.

Chicago region range map for the lyric cicada. Black dots indicate counties where the species occurs. Red stars indicate northernmost locations known through 2014. Yellow stars indicate northernmost locations found in 2015.

In Kane County, the new location was in Trout Park, at the north edge of Elgin. This represents a northward shift of 11 miles. Did the cicadas jump so far in just one year? That seems unlikely; I simply may not have looked in the right places in the past. I will continue to follow this each year, as I am doing for species such as the jumping bush cricket and broad-winged tree cricket, and in time should be able to get a sense of how rapidly the range expansion is occurring.

Bush Cicadas

by Carl Strang

Illinois has lost nearly all the remnants of its original prairie. Thanks to the efforts of conservation agencies and private organizations you can find prairies to enjoy, but these are restoration projects for the most part. Restored prairies are nice gardens, but they lack a significant portion of the animal life. It’s a mistake to assume that “if you build it they will come.” Too many obligate prairie insects and other animals are not good dispersers. The highest priority has to be preserving the remnants, when there is a choice between devoting resources to that or to developing restorations.

A case in point is the prairie cicada, which I have featured here in the past. Another is the bush cicada. I made a trip south of the Chicago region last week to get some experience with that species, so I would know what to listen and look for in my 22-county survey area. A 2-hour drive took me to the southern fringe of Iroquois County, to the Loda Prairie State Nature Preserve.

This remnant is only 12 acres, but its quality is excellent.

This remnant is only 12 acres, but its quality is excellent.

The term “charismatic fauna” is over-used. The bush cicada is the first Illinois insect I have encountered to which I would apply that term.

For one thing, they are big and colorful.

For one thing, they are big and colorful.

They also are noisy like the other species in genus Neotibicen (formerly Tibicen, the change justified in a paper just out this year from the UConn cicada group plus an Australian researcher). I was pleased to find bush cicadas are fully as audible as our familiar Neotibicen species.

Linne’s cicada, for instance.

Linne’s cicada, for instance.

The song is like a slowed lyric cicada song, the pulse rate closer to that of Linne’s but with sharp, separate pulses. The singing was in bouts, with sometimes 10 minutes of silence between, so that the males seemed to cue their singing off of one another. They also were very active, many of the males flying to a new perch after every song. Though their flight generally was well controlled, once one bounced off the side of my head.

A male bush cicada in full song.

A male bush cicada in full song.

In the following days I sought them in several Chicago region counties, without success. The silence of those prairie remnants, some suffering from invasion by gray dogwood and other problem plants, was a sad contrast to Loda Prairie. In fairness, though, the bush cicada is primarily a southern and western species that may never have reached into the Chicago region. That won’t keep me from continuing to seek it here, though.

%d bloggers like this: