Scouting Fulton and Pulaski

by Carl Strang

When I updated my regional guide to singing insects over the winter, I decided to add range maps. This was a little premature, because I barely have begun the survey work, but I also had sources in the scientific literature to augment my own observations.

Here is a page from the guide. The map shows the counties I decided to include in a region centered in northeast Illinois and northwest Indiana, but extending a little into Wisconsin and Michigan. Black dots are recent observations, open ones are from the literature, which often goes back more than 5 decades.

Here is a page from the guide. The map shows the counties I decided to include in a region centered in northeast Illinois and northwest Indiana, but extending a little into Wisconsin and Michigan. Black dots are recent observations, open ones are from the literature, which often goes back more than 5 decades.

Another winter project then became to identify sites in all the counties where I could focus my survey efforts, mainly state parks and other public properties. The plan is to start visiting them this year, noting species I can identify through sight and hearing without collecting. If collecting seems necessary, I can seek permits in a future year, but there will be plenty to do without going to all that trouble yet.

Over the weekend I visited sites in Fulton and Pulaski Counties, Indiana, which are the empty counties in the snowy tree cricket map at the eastern end of the bottom row. In Fulton County I had decided to focus on the area around Lake Manitou at Rochester. This proved to be a good choice, as there appear to be representative habitats of nearly every type.

The Judy Burton state nature preserve, for instance, has extensive meadows undergoing prairie restoration, and woodlands, all with maintained trails.

The Judy Burton state nature preserve, for instance, has extensive meadows undergoing prairie restoration, and woodlands, all with maintained trails.

It is early in the season, but I was able to add county records for the green-striped grasshopper and spring trig.

Pulaski County boasts the Tippecanoe River State Park and Winamac Fish and Wildlife Area. The state park is almost entirely forested, so I didn’t spend much time there (early singing insect action is in the meadows and prairies), but it will be great later in the year. The fish and wildlife area has a more diverse array of habitats.

This weedy field had many displaying green-striped grasshoppers and a few spring field crickets, both of which I now can add to the maps.

This weedy field had many displaying green-striped grasshoppers and a few spring field crickets, both of which I now can add to the maps.

This grasshopper, photographed in the above field, appears to be a species of Melanoplus, and so not a singing insect.

This grasshopper, photographed in the above field, appears to be a species of Melanoplus, and so not a singing insect.

As time permits, I will be returning to these areas later in the season. I am looking forward to making the acquaintance of many places in the region’s other counties, as well.

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Spring Field Cricket Survey

by Carl Strang

The spring and fall field crickets arguably are our most familiar singing insects. The two species are common, span the season from spring to late fall, and their identical songs are easily recognized chirps. Physically, spring and fall field crickets are essentially identical.

Fall field cricket (female)

Fall field cricket (female)

Developmentally and ecologically they are different, however. These days we are hearing spring field crickets, which overwinter as nymphs, mature in late April or May, and finish in mid-July. The figurative baton then passes to the fall field crickets, which overwinter as eggs in the soil, mature after mid-July, and continue into October or early November. These are two different survival regimes, and the spring field crickets arguably have the tougher challenge. Winter would seem to be easier to survive as a buried quiescent egg than as a nymph. I have been testing this idea by surveying the two species in DuPage County, and recently completed the spring field cricket part of the survey. I drove 3 routes in eastern DuPage in the evenings, listening with the car windows open. The crickets’ songs are sufficiently penetrating that I can expect to hear them, at least well enough to get a general sense of where they are and where they’re not.

Here’s the composite map to date. Green dots represent locations with both species, yellow show places with only fall field crickets, and blue with only spring field crickets (so far).

Here’s the composite map to date. Green dots represent locations with both species, yellow show places with only fall field crickets, and blue with only spring field crickets (so far).

As you can see, there are many blue dots in the eastern half of the county. Many, perhaps most or all, will become green when I repeat these routes in late summer or early autumn. The impression I formed while driving around is that there are pockets of crickets, scattered and somewhat isolated, with a lot of empty space between them. Some populations are relatively large, but some of the blue dots represent single singers. Spring field cricket habitat is narrower, it seems, needing to supply better winter shelter, but I will be better able to draw tentative conclusions after the survey drives for fall field crickets later this year.

Bioblitz Species Hunt

by Carl Strang

Yesterday I introduced last weekend’s bioblitz at Connor Prairie in Indiana. My focus as a bioblitz participant is on singing insects, of course, but those are few early in June, even as far south as Indianapolis. Not to worry, though. There were teams focusing on many groups of organisms, but others had no specialists to address them, so I enjoyed filling in where I could. Odonata were one such group.

Twelve-spotted skimmer

Twelve-spotted skimmer

Powdered dancer

Powdered dancer

After much pondering, I concluded this was a female cobra clubtail. Indiana has a similar species, the handsome clubtail, but certain details ruled it out.

After much pondering, I concluded this was a female cobra clubtail. Indiana has a similar species, the handsome clubtail, but certain details ruled it out.

For instance, the C-shaped line at the top of the side of the thorax is connected, and apparently too thick for a handsome clubtail.

For instance, the C-shaped line at the top of the side of the thorax is connected, and apparently too thick for a handsome clubtail.

I also saw three bumblebee species.

Bombus fervidus was an easy ID.

Bombus fervidus was an easy ID.

There was a butterfly team, but I took advantage of photo ops that presented themselves.

Variegated fritillary

Variegated fritillary

Nevertheless, my main interest was singing insects. I found 4 species, and botany team leader Scott Namestnik added a 5th.

Green-striped grasshoppers were common, as were spring field crickets.

Green-striped grasshoppers were common, as were spring field crickets.

I saw a single sulfur-winged grasshopper. Scott ran across a pocket of Roesel’s katydid nymphs. Connor Prairie is about even with the Crawfordsville area where I found Roesel’s a couple years ago. So far, none have turned up farther south in Indiana.

The final species is worth a blog post all its own (to be continued).

Update

by Carl Strang

Circumstances have prevented me from gathering much new blog material for the past week and a half, but I hope to have more to share soon. The bird migration continues, but there’s only one photo in the hopper.

White-crowned sparrow, Mayslake Forest Preserve

White-crowned sparrow, Mayslake Forest Preserve

As for singing insects, the first few spring field crickets began singing in Marshall County, Indiana, last week, but I have yet to hear any farther north (DuPage County, Illinois).

The one significant new development came yesterday, as I was running the trails at Herrick Lake Forest Preserve. A grasshopper flew up from the trail in the large meadow of the preserve’s southeast corner. It had hind wings that were bright yellow with broad black edges. This was the first opportunity to take advantage of my recent literature research on possible new singing grasshoppers. It turns out there is only one band-winged grasshopper with that color pattern that matures so early in the season, the sulfur-winged grasshopper (Arphia sulfurea), and so I can already shift one species from the hypothetical list to the verified list for the region.

Field Cricket Final

by Carl Strang

In September and early October I revisited driving routes I had followed in the spring, listening for fall field crickets (FFC) as I had done in May and June for spring field crickets (SFC). Then, I had noticed that SFC were limited largely to places where dense herbaceous vegetation provided shelter for overwintering nymphs. FFC spend the winter as eggs buried in the soil, and so are less vulnerable to the stresses of the cold season. Here is the current map showing the distribution of the two species in DuPage County:

Green circles represent locations with both spring field crickets and fall field crickets. Blue circles indicate spring field crickets only, yellow indicate fall field crickets only.

Clearly both species occur together in most places. Fall field crickets are more likely to occur alone than spring field crickets, in keeping with the spring observation. This year’s surveying was done in western DuPage, and next year I plan to fill in more of the eastern part of the county. If the results continue to show the pattern that appears to be emerging to date, the eastern part of the county, which became urbanized earlier and more completely than the western part, will continue to show fewer SFC because of its historical paucity of safe nymphal overwintering sites. The existence of locations with SFC but no FFC remains to be explained.

Learning to Identify Insect Songs

by Carl Strang

One of the obstacles to a singing insect monitoring program is the large number of various songs that need to be learned for identification. This is not really much different from learning bird songs for breeding bird monitoring, however (except that the total number of species is smaller here). Instead of being daunted by the entire process, it is possible to take the learning process in stages, beginning with the songs that are common and easy to recognize, the ones you have been hearing all along but simply didn’t have the species labels. Here is a list of a dozen suggested species to start with in the first stage: spring field cricket/fall field cricket (their songs are identical), Allard’s and striped ground crickets, snowy tree cricket, common true katydid, black-legged meadow katydid, greater angle-wing, round-tipped conehead, dog day cicada, scissor-grinder cicada, and Linne’s cicada (for more information on these species, try the tags at the head of this post).

Snowy tree cricket, one of the species on the starter list

This list and those that will follow are for northeastern Illinois and northwestern Indiana. There would be substitutions in other parts of the country (I encourage readers elsewhere to make comments here with their own suggestions). Go to reference recordings of these species’ songs, either on-line at the Singing Insects of North America website or through the CD that accompanies the Songs of Insects book. It is not too late this year to hear many of the species on this list on the warmer days, though some are finished or nearly so.

My recommended species list to focus on in the second stage of learning consists of 8 species and groups of species: greenstriped grasshopper, gladiator meadow katydid, Roesel’s katydid ( three species that sing relatively early in the season), and then later, Carolina ground cricket, Say’s trig, sword-bearing conehead, two-spotted/narrow-winged tree crickets (no need to worry yet about separating the two), and the meadow tree cricket group (3-4 species whose songs are essentially identical to the ear and will remain so).

Roesel’s katydid is a species from the second-stage list.

This list of common species either will take you to additional, though still readily available, habitats, or else require a little more of a practiced ear (which practice you got with the first species group). In particular, seek out and spend some time getting familiar with the songs of the Carolina ground cricket and Say’s trig. They need a little more effort to recognize in the field, but once you have them, they will be touchstones for many other species (much as robin songs are for learning bird vocalizations). If you are starting now, you might push the Carolina ground cricket to the first list, as it is one of the few species singing on the cooler days and evenings.

Once you have mastered the second list of species, you are ready for the more subtle distinctions needed to distinguish the songs in the third species list. This includes separating out the song of Linne’s cicada from similar songs by the lyric cicada, and in some areas, swamp and/or northern dusk-singing cicada.

Linne’s cicada

Also, by this point you are ready to distinguish the two-spotted tree cricket song from that of the narrow-winged tree cricket. Also, the broad-winged tree cricket should stand out now from other long-trilling species. In addition, you no doubt have noticed and begun to puzzle out other species that are more idiosyncratic in their distribution or smaller in numbers that you have encountered in your favorite places.

And that brings you to the fourth stage, learning the songs of whatever remaining species may live in the area you wish to monitor. For this you will need a regional guide. In the Chicago region, you can meet this need with the guide I am developing. It is available for free as a .pdf e-mail attachment. Simply request it at my work e-mail address: cstrang@dupageforest.com

As you are learning and listening, pay attention to which songs you can hear clearly, and at what distances, and which are marginal. This will inform the limitations you will need to address or acknowledge in your monitoring.

Early Singing Insects

by Carl Strang

To this point in the season I have heard singing males of 10 insect species in northeast Illinois. All but one began earlier than in any of the years from 2006 to 2011. This is consistent with more general insect phenology this year, and is attributable to a mild winter and a warm March which heated the soil earlier than usual. The only species with a later starting date was the spring field cricket, a species I usually hear first while running or bike riding, activities my back trouble prevented during the critical time period. And yet, despite that limited mobility, I have recorded dates for the other 9 species that ranged 5-22 days earlier than in any previous year (4 of the previous records were in 2007, 5 in 2010, 1 last year; they add up to 10 because of a tie). The only other case perhaps worth singling out was the broad-winged bush katydid, 22 days earlier than last year’s previous record. This species is not abundant or widely distributed, and I suspect it has a longer, earlier season than I have realized before. I should make some effort in future years to get a better handle on its starting and ending dates.

Broad-winged bush katydid

For those who may be interested, here are all the first song dates this year so far. Greenstriped grasshopper 3 April, 17 days earlier than the previous record. Spring field cricket 25 May, 20 days later. Roesel’s katydid 29 May, 11 days earlier. Protean shieldback 5 June, 7 days earlier. Linne’s cicada 14 June, 12 days earlier. Gladiator meadow katydid 14 June, 7 days earlier. Dog day cicada 15 June, 5 days earlier. Scissor-grinder cicada 19 June, 13 days earlier. Broad-winged bush katydid 23 June, 22 days earlier. Lyric cicada 24 June, 6 days earlier.

Spring Field Cricket Observations

by Carl Strang

There are indications that the season for spring field crickets is winding down. That is not surprising, given the early start that this year has given to insects, but it means suspending my driving survey until the fall field crickets are singing. I was able to cover a large part of western DuPage County in the time I had, though, and I was able to make some observations.

Only rarely were spring field crickets to be found away from areas dense with tall grasses.

Thus forest preserves, railroad corridors and some highway corridors were the most consistent places where I heard spring field crickets singing, and all high-density clusters of the insects were in such locations. That is not to say, however, that all fields with tall grasses had crickets.

One obvious example is the friary site at Mayslake Forest Preserve, which was bare soil until recently seeded with grasses.

History appears to be important here. Spring field crickets would seem to have limited dispersal ability, and local extinction is not readily followed by new invasion unless a source population is really close. This gives an inkling of what may differentiate the spring and fall field crickets. Spring field crickets overwinter as relatively vulnerable nymphs, and need more robust shelter from severe winter conditions. Fall field crickets overwinter as eggs, relatively safe as they are buried in the soil. This allows them to live in a wider variety of places, and makes them less susceptible to local extinction. At least now I have a hypothesis to work with.

Cruising for Crickets

by Carl Strang

Spring field crickets are singing in northeast Illinois, and it’s time to resume my study of field cricket geography in DuPage County. I’m trying to sort out why our two sibling species, the spring field cricket and the fall field cricket, don’t always occur together.

Green colors mark where I have found both spring field crickets and fall field crickets in previous years. Yellow locations had only fall field crickets, blue had only spring field crickets.

As you can see, there are large gaps I haven’t explored with respect to this question, so I plan to address this with some driving tours. The crickets sing loudly enough to be easily heard through open car windows when it’s calm, and sing consistently in the early evening, so that is when I have begun to seek them. The focus for now will be spring field crickets, and in the late summer I can follow up with a fall field cricket search.

A Case of Displacement?

by Carl Strang

I recently returned from a brief trip out to Maryland for the wedding of my youngest nephew, Brice, to new niece Rachel.

My best photo from the ceremony, a symbolic blending of sands.

While staying at my brother’s house I took some morning walks, and heard unfamiliar crickets trilling. I had failed to bring recording equipment, and was unable to find one of the crickets. They were locally abundant ground-dwellers, but this was early in the season, which should rule out most possibilities even on the Eastern Shore. I believe these were southeastern field crickets, which have both spring and fall adults and are reportedly one of the most common crickets in their range. The song, a continuous trill interrupted by occasional stutters, was close to reference recordings for the species.

The thing is, I was hearing spring field crickets all along the drive out to Maryland, and that species is mapped throughout the DelMarVa peninsula, but I never heard one in the limited portion of that area I visited, mainly around Easton.

Spring field cricket

The Singing Insects of North America  range map for the southeastern field cricket establishes it in the southern tip of the DelMarVa peninsula, and Easton is just a short distance north of there.

Southeastern field cricket range map, from the Singing Insects of North America website.

So all of this has me wondering: was I in fact hearing southeastern field crickets, and if so, are they expanding north and, at least in the Eastern Shore area, displacing spring field crickets? Perhaps I will have more time and mobility on a future visit to check that out.

(Note: natural history information on southeastern field crickets from: Jang Y (2011) Male Responses to Conspecific Advertisement Signals in the Field Cricket Gryllus rubens (Orthoptera: Gryllidae). PLoS ONE 6(1): e16063. doi:10.1371/journal.pone.0016063).

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