There are currently outbreak choruses of hundreds of truncated true katydids (Paracyrtophyllus robustus) in central Texas. I’ve been hearing them every night and finally managed to spot a male calling away not so high up in the trees. Like in cicadas, their rhythmic calls often escalate into long shrills — maybe when they are feeling the most excited… or competitive. Males have a file on the underside of the left tegmen (thickened forewing) and a sclerotized scraper on the edge of the right tegmen. The scraper runs along the file to vibrate the wings, and the sound resonates through a chamber formed by a triangular group of wing cells called the harp and a transparent circular area called the mirror. Unfortunately this katydid stopped calling once I spotlighted him and shortly after ran back up to the canopy. Hopefully I can film one calling another day.
Read about sound modulation in katydids here. Photographed after pursuit [3]
