by Kate Redmond
Say’s Trig
Howdy, BugFans,
The BugLady has always wanted to see a trig, because – what an interesting name for an insect (a name, it turns out, that’s a shortened version of its family, Trigonidiidae). Trigs, members of the grasshopper/cricket/katydid order Orthoptera, are also called Sword-tailed crickets and Winged bush crickets. They’re crickets, but they’re not in the same family as the common, black field crickets of fall (family Gryllidae). The BugLady still wants to see a trig – these pictures were taken by BugFan Dave, who’s finding some very cool things as he rehabilitates his property with native plantings (and he’s having fun and photographing the heck out of it, too!). Thanks, Dave!
Trigs are smallish crickets that live in leafy spots in grasslands, edges, wetlands, and woods east of the Rockies, usually close to the ground. There are 19 species of trigs in North America, and they come in brown, green, and Handsome/Red-headed https://bugguide.net/node/view/2401012/bgimage.
SAY’S TRIG (Anaxipha exigua) (Anaxipha means “upraised sword”), in the brown trig genus Anaxipha, lives in the lower levels of the vegetation in the northeast quadrant of the continent. Along with wetlands and grassy areas, it likes honey locust trees (and, apparently, Dave’s house). Adults and nymphs https://bugguide.net/node/view/867950/bgimage are seen from mid-summer on, disappearing as fall progresses.
It’s one of the larger trigs, with males measuring about ¼” long, and females a shade longer, both with a lovely, stripey head. Dave’s trig was a male, with two unsegmented, sensory appendages called cerci (singular: cercus) at its rear. Females have two cerci plus an upcurved ovipositor (hence the name “sword-bearing cricket”) https://bugguide.net/node/view/697120/bgimage. Most trigs have short wings, but some are macropterous (have longer wings) https://bugguide.net/node/view/1880530/bgimage.
Like other trigs, the Say’s Trig is an omnivore, feeding on vegetation, insect eggs, and small, soft-bodied insects. They are fed upon by birds and other critters that prey on insects. The BugLady is always startled to be reminded that omnivory is not uncommon in the grasshopper/cricket bunch.
They have the ability to climb up the sides of collecting jars like a spider – but not like your average cricket.
Males make sound by stridulation – rubbing bumps/pegs (the file) on the forewing against a sharp edge (the blade) on the hind wing. In fact, one way to ID Say’s trigs is by counting the number of bumps/pegs on the file (Say’s trigs’ files have about 190 teeth). If you’re going to make noise, you need to hear it, too, and they have hearing organs (tympanums) on their front legs that allow them to detect vibrations.
They sing continuously and may sing day or night. The song is a trill http://minnesotaseasons.com/Insects/Says_trig.html (scroll down), that’s described as “high and shimmering,” “ a continuous, fast tinkle,” “pulsing at 35 – 40 per second,” “very loud for such a small insect,” and “can be heard from one hundred or more feet away.” The BugLady usually has to turn the volume way up and cup her hands behind her ears to hear some of the crickets and katydids on recordings, but she can hear this one. In lower temperatures, the song is slower, and in warmer weather, the song may be higher-pitched. Nearby tree crickets (from yet another cricket family) sing at a lower pitch. Males like to perch above the ground when they sing, concealed by a leaf, so they’re impossible to spot.
Nota Bene: remember that trigs exist deep in the vegetation, where the shelter of leaves creates a “microclimate” in which light and sound levels, humidity and precipitation, temperature, and wind speeds may differ from areas just a few feet away (the concept of microclimates is oh-so-important to the understanding of ecology).
Trigs – Very cool!
Kate Redmond, The BugLady
Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/