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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