Friday, October 2, 2009
Name: The pine tree cricket is Oecanthus pini. There are at least 16 species in the genus. They are in the same order of insects, Orthoptera, as grasshoppers, katydids and the other crickets like field and ground crickets.
When and where found: I found this particular tree cricket on a senna bush in my garden back in August but I know there are still tree crickets around because I hear them singing, particularly at night. They will continue to sing until the first frost. They are much more likely to be heard than seen for three reasons. First, they are usually up in the trees. Second, they are very well camouflaged, and third, they were not brought up in my family where rewards were highest for “seen but not heard.”
Distinguishing characteristics: A tree cricket looks like an anorexic grasshopper or katydid or maybe a green lacewing bug with special legs. You immediately notice the grasshopper-like hind legs. You can distinguish it from katydids by its slender body, from most grasshoppers by its long antennae, and from other crickets by its pale green color. The pine tree cricket has a light brown head and thorax, green abdomen, and antennae that are about twice as long as the body. It is found in or around pines. It is very hard to tell it apart from the larch tree cricket, so I have made an assumption about its identity on the basis of habitat. The one I found is a female. She has narrow wings held very close to the body. The males have very broad wings.
Dating and mating: The mating song of tree crickets that we hear throughout late summer and early fall is made only by the males. They raise those broad wings above their abdomen and rub the edge of one wing against the other to make a trilling sound. Crickets tend to be “right-wingers.” The song is made with the right wing on top. But right or left, the females want more than a come-on-over phone call. The male obliges with another softer song, a courting song, that we don’t hear. Crickets have receptors on their front legs that act as their “ears” and they can hear this other song. This is still not enough for the female. The icing on the cake is the “honey” exuded by a pair of glands on the thorax of the male. The female finds this very compelling. She stays and feeds long enough for the male to deposit a spermatophore.
Unintended consequences: The singing of the tree cricket also attracts the attention of certain parasitic flies which pay a rapid visit and deposit an egg in the body of the cricket.
Life cycle: The female tree cricket deposits her eggs in a slit that she cuts in a twig. The eggs remain there through the winter, hatching as nymphs in spring of the following year. These young tree crickets feed on aphids and other small insects. They grow and by mid- to late summer they will have wings and be mature.
Trade-offs: Twigs are sometimes killed by the egg-laying process but this is usually more than offset by the diet of the juvenile tree crickets.
Sources: There is a website devoted to tree crickets at www.oecanthinae.com/index2.html where you can see the pine tree cricket as well as other species and play recordings of their songs; Insects, their Natural History and Diversity, by Stephen A. Marshall; A Guide to Observing Insect Lives, by Donald W. Stokes; my favorite insect guide book, the Kaufman Field Guide to Insects of North America by Eric R. Eaton and Kenn Kaufman; and my favorite insect website www.bugguide.net (search for tree cricket).
What are you finding: If you find something living or growing in your yard or on one of your walks in the woods and you think it might be interesting or you are just curious about it, drop me a note at firstname.lastname@example.org. ∆
© 2009 The Carlisle Mosquito