Southern Lessons

by Carl Strang

This year’s chapter in the series of annual bioblitzes organized by the Indiana Academy of Sciences took place at Eagle Creek Park in northern Indianapolis on June 2-3. This is early enough in the season that there were few singing insects for me to find, but I was able to gain valuable experience with two southern species that occur or have occurred in the Chicago region.

The first of these is the spring trig.

Female spring trig at Eagle Creek.

This species of tiny cricket first was described in 2014. That is surprising, given its abundance in southern Indiana and its extensive range beyond the state. It proved to be common in a range of habitats at Eagle Creek Park, from woodland edges to grassy meadows.

Spring trigs appear plain-faced to the eye, but bright light and magnification reveal a pattern of fine dark lines.

I learned more about the spring trig’s habitat, and found that I can hear them easily while driving at speeds of 30mph or less. This allowed me to get clarity on the species in the Chicago region. Driving in the southernmost counties, I found widely scattered small colonies in Fulton and Jasper counties, at road edges where wider bands of herbaceous plants were backed by woodlands. In the future I expect to find them in southern Pulaski and Newton counties, too, but not north of there.

Eagle Creek Park also has a large population of northern wood crickets.

The northern wood cricket is a forest species that is smaller and blacker than the spring field cricket, which could be heard chirping in the park’s meadow areas.

The spring field cricket is a few millimeters longer, typically has bronzy wings, and has a proportionately broader head and thorax.

Recordings I made during the bioblitz, and at home with a captive male, have provided further clarity on northern wood cricket song characteristics. Their chirps may never have 4 pulses (commonly 2 or 3), and almost never rise above 5 kHz in pitch, where spring field crickets often have 4-pulse chirps, and seldom drop below 5 kHz. Habitat also helps separate the two. I dug deeper into the literature, and learned more about historical records of the species in two Chicago region counties. Those observations were made in 1902, and I went to the sites in the weeks after the bioblitz. Northern wood crickets no longer occur there. I believe the records are correct, but that the crickets have gone extinct in those places. Northern wood crickets are reported to be sensitive to forest fragmentation, perhaps especially so in the northern fringe of their range, and such fragmentation clearly took place where they once were found in Lake and Marshall counties. I will continue to check the region’s larger surviving forest blocks, but it seems likely that the species no longer occurs in northern Indiana.

Incidentally, the other expected early-season singing insect, the green-striped grasshopper, lives in Eagle Creek Park’s meadows and prairie areas.

Next year’s bioblitz is expected to take place in one of my counties, and I am looking forward to the experience.

 

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First SFC’s

by Carl Strang

On Sunday afternoon, during a bike ride through Fermilab, I heard the first spring field crickets of the year. They had just begun, as there were only 3 of them. This is the third earliest date I have heard them in DuPage County, a little surprising given the late spring, though the deep snow that covered the ground most of the winter certainly provided the nymphs with protection. If a larger population survived, some statistical outliers could be starting up earlier than otherwise would be the case.

Cheating a little here: this is a fall field cricket female, but that species is physically identical to its spring sibling species.

Cheating a little here: this is a fall field cricket female, but that species is physically identical to its spring sibling species.

Apart from such uncommonly encountered critters as sulphur-winged grasshoppers and spring trigs, the next common singing insects to mature should be the predaceous katydids (Roesel’s katydid and the protean shieldback), and gladiator meadow katydids. By then I hope that the spring field crickets will have built numbers to the point where I can finish my county survey of their distribution.

Sound Ideas: Trigs

by Carl Strang

The first field recording I made this year was at the Connor Prairie bioblitz near Indianapolis, of a mysterious cricket that sounded just like the familiar Say’s trig but was in a mesic prairie habitat and was singing too early in the season. Here is what it sounded like:

With much effort I caught one, and this clearly was no Say’s trig. I collected him.

The head is entirely dark, unlike Say’s trig (see below).

The head is entirely dark, unlike Say’s trig (see below).

It proved to be a spring trig, in the same genus but a distinct species, and in the process of being described by specialists. Until that happens, its label in the Singing Insects of North America website is Anaxipha species G.Say’s trig has a paler head, with a dark line descending diagonally from each compound eye.

Say’s trig female

Say’s trig female

Say’s trig is abundant throughout the Chicago region, in marshes, wet meadows and bottomland woods. So far I have found the spring trig fairly common in Fulton County, Indiana, at the southeast corner of the region, but it diminishes to rare individuals in northeast Illinois. Its preference is grassy prairies and mesic meadows.

The region’s third trig species is the handsome trig, a cricket that seems to prefer brush or thinly wooded edges close to wetlands.

Handsome trig

Handsome trig

Its song is distinct from the other two. Each pulse of its trill has, at least to my ear, a sharp clicking or percussive quality:

A comparison of sonographs shows this difference.

Spring trig sonograph. The selected area is half a second of the recording.

Spring trig sonograph. The selected area is half a second of the recording.

Handsome trig sonograph. Again, half a second is selected.

Handsome trig sonograph. Again, half a second is selected.

The narrow, sharp attack at the beginning of each pulse distinguishes the handsome trig’s song.

DuPage Robust Coneheads

by Carl Strang

Last year, while conducting an evening survey drive to map fall field cricket distributions in my home county of DuPage in Illinois, I was passing through Springbrook Prairie Forest Preserve when I thought I heard a couple robust coneheads singing.

Male robust conehead in singing posture, Newton County, Indiana

Male robust conehead in singing posture, Newton County, Indiana

This was surprising, and I wasn’t able to follow up in 2012, but it was on this year’s research checklist, and on Monday evening I heard them again in the same location. I found a place to park, and to make a long story short was able to confirm my suspicion (a later sonograph analysis of the recording I made will determine whether this was a robust conehead or, less likely given the loudness of the song, a false robust conehead).

This discovery was surprising because in general I have been finding them, as researchers in past decades also have noted, mainly in areas with sandy soils.  No such soils exist outside children’s playgrounds in DuPage. On the other hand, no lesser a light than Richard Alexander listed DuPage County as a place where he had found the species a few decades ago. This is not a simple matter of latitude, as robust coneheads are abundant in sandy Lake County, Illinois, to the north. This species joins the tinkling ground cricket and spring trig as species that I have found in the county, but only in extremely small numbers in one or two places. DuPage County, out of all the 22 counties in my regional survey, is the one I have surveyed most thoroughly, and for nearly 8 full seasons. These few locally rare species are indicators that there probably will be holes in my distributional records for all counties, and so these will need to be judged accordingly. I will need to continue searching for new sites through the seasons and years, as long as I am able to do so.

Slow Day

by Carl Strang

Saturday was cool with intervals of rain, so there wasn’t much to be done with singing insects. I checked out Springbrook Prairie in the morning, and Tri-County (JPP) State Park in the evening, hoping for spring trigs, but no luck there.

Walking the trails at Tri-County, I found a dark grasshopper.

It was on the trail, had the colors of a green-striped grasshopper, but was large, perhaps an inch and a quarter long.

It was on the trail, had the colors of a green-striped grasshopper, but was large, perhaps an inch and a quarter long.

It was unable to perform a sustained flight. Somehow I missed the fact that it had lost one or both hind legs. I am not fully confident of my grasshopper anatomy, but this individual appears to be a female, which would account for the size. It is, then, an unusual brown female of the species (typically, females are green, males brown). And that was it for Saturday’s research production.

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.

Spring Trig

by Carl Strang

This is the story that made my participation in the Connor Prairie Bioblitz worth the trip. Beginning in 2008, I have heard occasional cricket trills that sounded identical to those of Say’s trigs, but were too early in the season. In 2008 my office was at Fullersburg Woods Forest Preserve, and on June 27 I heard one of those odd early songs. I also noted them on July 8 and 14 that year. In 2009 the first Say’s trig was singing on a more reasonable August 6, and in 2011 on July 31. In 2010 the first was on July 19 at Waterfall Glen, a little marginal perhaps but acceptable. Then last year I heard one near the Fox River in Kane County on June 10. Granted, last year was early phenologically, but this was completely out of line. I speculated that perhaps a rare few Say’s trigs hatched early and successfully overwintered as nymphs.

Then came last weekend’s bioblitz at Connor Prairie. This is too early to expect much singing insect action in the woods, so I headed straight to the large prairie restoration project west of the interpretive center.

View of the restored prairie from the balloon.

View of the restored prairie from the balloon.

The same area at ground level. This prairie first was seeded around 5 years ago.

The same area at ground level. This prairie first was seeded around 5 years ago.

There were plenty of spring field crickets chirping, as expected. But as I approached the taller grasses I also began to hear trills. Lots of them. Furthermore, they sounded just like Say’s trigs. On June 8. I began stalking these singers. Several times I got within 2-3 feet, but was never able to see one of the singing crickets in the dense grasses. When my approach stopped the singing, the cricket was able to outwait me. I was fairly certain they were above the ground, and so probably were not ground crickets. They became quiet in late morning. I heard one singing briefly in the afternoon, but that was it.

In the evening I returned, and as the sun slid to the horizon I was pleased to find that the mystery crickets were singing again. Again I tried stalking, and again was frustrated. Then, when yet another cricket stopped singing when I got within 2 feet, I shuffled my feet through the grass clump where his perch seemed to be, and up he hopped. I caught him in a vial.

He was a brown trig, but his head was entirely dark rather than pale with dark stripes as is characteristic of Say’s trig. I made the necessary decision and collected him.

Here he is, pinned and drying. The uniformly colored head is distinctive.

Here he is, pinned and drying. The uniformly colored head is distinctive.

The color, size and shape otherwise are similar to Say’s trig.

The color, size and shape otherwise are similar to Say’s trig.

I returned the next morning, but was unable to flush another male or sweep-net a female. None of my printed references mentioned anything like this cricket. I was able to connect to the Connor Prairie’s Wi-Fi, and searched the Singing Insects of North America website. Imagine my elation when I found it! This is an unusual instance of a species getting a common name before its scientific name is assigned. It has been designated the spring trig, Anaxipha species G. The SINA spreadsheet lists May and June dates, and gives a range that includes Indiana and Illinois, though apparently my cricket is the first specimen for Indiana. So, now there is another species to listen for in my travels. I will want to get some definition of this species’ season relative to Say’s trig. The reasonable assumption is that, unlike other Anaxipha, the spring trig overwinters as a nymph.

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