Grigs

Hump-Backed Grigs:

 

Cyphoderris buckelli. Buckell’s Grig. Drawing of male by Susan A. Wineriter, University of Florida.

 

Cyphoderris monstrosa. Great Grig. Drawing of male, by Mary Foley Benson. Fig. from Gurney 1939.

   Hump-Backed Grigs come from the family Prophalangopsidae, and there are three species that are found in North America, all of which are in the genus Cyphoderris. They can be found in coniferous forests, or in high altitude sagebrush in the north western part of the United States, and extending up into Canada.

   Hump-Backed Grigs are nocturnal insects, and are rarely found during the day. They hide in burrows, but come out at night. The males are found chirping away on tree trunks or anything else that protrudes from the ground. They always sit head down when chirping, and through the night will climb higher and higher until they are out of reach.

   It’s easy to tell whether an adult grig is a male or a female. If the grig’s wings cover half or more of its abdomen, then it’s a male. But if its wings are miniscule, then it is either a female, or if it is small, then it is a nymph.

   One interesting thing is that it’s also pretty simple to figure out whether a male has mated yet or not. You just lift up the upper wings to uncover the hind wings, and if the hind wings are damaged at all, the male has mated before, but if the hind wings are undamaged, then the male is a virgin. The reason for this is because when grigs mate, the female will chew on the hind wings of the male.

   The chirping is a high pitched trill that lasts several seconds, stops for a moment, then starts again. “Eeeeeeeeeeee! Eeeeeeeeee! Eeeeeeee!” The sound can be a little unnerving, as it sounds anything but nice, and even the sight of these creatures aren’t that friendly, but they really are quite harmless.

   You can hunt them at night by following their sound, but if you flash them with a light, they will stop their song, and will not start up again for a few minutes. The way I hunt them is I either shine the light on the ground in front of me or don’t have my light on until I pinpoint what tree the grig is on. Once you have pinpointed the tree the grig resides on, you can search the trunk with your light.

   Again, though they look quite fierce, they are quite harmless, and will only bite if grabbed the wrong way. The bite doesn’t even hurt, but is merely a little surprising, and may cause you to drop the grig. Just grab it by its thorax with its legs held against its body, and drop into an awaiting container.

   The succession of trills produced by the male are made at wing stroke rates of 50-75 (at 77 ºF) a second. The forewings have both a “file” and “scraper” which produce the sound, and will amplify and broadcast the trills; the right and left forewings both have equally developed files and scrapers. They will alternate between which wing is on top at rest. To what extent the grig will switch between the left and right files is not established. This action is called “switch wing stridulation”.

   Though scientists have separated the genus Cyphoderris into three species, it is most likely that all came from the same created kind. There are only very minor differences between the three different species, but it is still interesting to examine these, and to see what diversity God has put in his creation.

   The species of grig that will be found in the Cascades of Oregon and Washington, and specifically Paulina Lake, will most likely be the Great Grig (Cyphoderris monstosa). But just in case of undocumented biogeography, here’s a key that shows some subtle, but interesting differences:

Lateral view of male subgenital plates of Cyphoderris. Fig. from Morris & Gwynne 1978.

   Not only are the back ends of the three species different, but their songs too. The songs of C. strepitans and C. buckelli are nearly indistinguishable, but there is a difference between the song of C. monstrosa. At any temperature, C. monstrosa has the higher pulse rate. Though a grig’s song is not as reliable as the Snowy Tree Cricket’s chirp is, it does follow a pattern. The warmer it is, the more pulses per second.

Relation of pulse rate and temperature in the calling songs of hump-winged grigs. (S is from Spooner 1973.) Fig. from Morris & Gwynne 1978 (slightly modified). Converted to Fahrenheit.

  

   Truly God has blessed us with a diverse and abundant amount of creatures. Everywhere we go we find different kinds of insects. In some places you might find field crickets, other places tree crickets, or katydids, or even cicadas. And last, in the Cascades and elsewhere, you find the Hump-Backed Grigs. God has created a symphony for us to enjoy at night, and to lull us to sleep. God is wonderful!