by Carl Strang
One of the nicest aspects of scientific inquiry is the discovery of other people pursuing shared interests. My own study of singing insects in northeast Illinois, northwest Indiana and adjacent counties in Wisconsin and Indiana has placed me in contact with Gideon Ney, whose pursuit of coneheaded katydid evolution in his Ph.D. thesis work at the University of Missouri has added the marsh conehead and slightly musical conehead to the region’s species list. Dennis Nyberg and associates at the University of Illinois Chicago have led me to the short-grass prairie cicada. Botanist Scott Namestnik and I have collaborated in mapping the regional distribution of Roesel’s katydids. Lisa Rainsong conducts a similar regional survey of species in the Cleveland area, allowing a valuable comparison of notes. And now I owe my thanks to Nancy Collins for introducing me to the pine tree cricket. Nancy is one of those rare people who develop such a strong interest in some aspect of natural history that they go on to make genuine contributions to science. She has traveled through the U.S. and into Central America searching for tree crickets, and has been involved in the discovery of new species. Her website provides an excellent overview of this charming group of insects.
Nancy came out to the Bong Recreation Area when I was surveying the southeast Wisconsin counties a couple of weeks ago, and helped me learn to recognize the song of the pine tree cricket. She also provided a male for me to photograph and record in an isolated indoor setting.
I had not focused on this species because the references seemed to indicate that it is only on the fringe of my area. Thanks to Nancy I now expect to find pine tree crickets throughout the survey area. Already I have found two populations in DuPage County, for instance, one of them at Mayslake where I work, and the other two miles from my home, at Fermilab. The Fermi population is particularly instructive, because the groves of conifers hosting the crickets are widely separated by expanses of prairie. This is a small insect with a narrowly defined habitat, but impressive dispersal ability. I suspect they have been able to jump around mainly by their affinity for red cedars, which readily spring up in open areas where birds disperse their seeds after eating the berry-like cones.
The song is not particularly intrusive, but easily recognized if you know what to listen for. Approach a large grove of coniferous trees in late summer or early autumn, late afternoon or early evening, and listen for a steady, high-pitched, sweet-toned trill. No other singing insect in the region has this peculiar attachment to conifers. The song of a single cricket is not particularly loud, but a chorus of them adds up significantly, and I had no trouble hearing those at Fermilab as I passed the spruces and cedars on my bicycle. Interestingly, and somewhat ironically, there were fewer in the pine groves.