The Carlisle Mosquito Online

Friday, July 31, 2009

 

July trio

Today’s column is sponsored by the letter “S.” We have a sphinx moth, a stinkpot and a sawyer.

First, the sphinx: sphinx moths are medium to large moths. Their name is reputed to come from the sphinx-like position adopted by the larvae when alarmed. This particular one, found by Bonnie Miskolczy on Bastille Day, is the Virginia Creeper Sphinx Moth or Darapsa myron, also known as the Grapevine Sphinx. There is no prize for guessing what the caterpillars (larvae) feed on – but did you know that Virginia Creeper, grape, and the other common food plant, Ampelopsis or porcelain-berry, are all in the grape family (Vitaceae)? The larvae get to be about two inches long and look very similar to other sphinx moth larvae that anyone who grows tomatoes has probably seen, the tomato hornworm. Adult moths feed on flower nectar. They wear olive-green camouflage colors and have a wing-span of up to two-and-a-half inches. They lay their eggs in twos or threes on the underside of leaves of the host plant. They hatch in about four or five days and eat their egg shells. At our latitude, there will be two broods a year so you may see them up through September.

Musk Turtle: The Musk Turtle, Sternotherus oderatus, is a small turtle which is also known as the stinkpot because it is able to emit a pungent fluid. I found this one on July 16 as it was crossing North Road at Great Brook Farm State Park beside the pond that is near the main parking lot. At the time, I didn’t know it was a stinkpot, and I also didn’t know of its reputation as a particularly aggressive turtle with a long neck and the urge to bite the hand that holds it. This turtle was atypical for its species in that it didn’t stink and it didn’t bite. It had a typical size of about four -and-a-half inches long and the dark gray carapace was quite high domed. The plastron, the shell on the underside, was quite narrow and extended out to the edges only in two sections near the middle. Musk turtles are not on the Massachusetts list of endangered animals but they are listed in Vermont and Maine. This is the first one I have ever seen.

Sawyer: On July 20, Warren Spence was a bit startled when a large beetle landed on his shirt while he was cutting wood in his yard on Carroll Drive. Both Warren and the beetle are Northeastern Pine Sawyers. The beetle is Monochamus notatus and just a glance tells you that it is a member of the longhorned beetle family, the span of the antennae being over six inches.

This one is a native beetle not to be confused with the very destructive and dreaded Asian Longhorned Beetle that has been in the news lately because of the measures taken to eliminate an infestation in the Worcester area. Northeastern Pine Sawyers are attracted to freshly cut conifers, especially in full sun, where they look for mates and lay eggs in holes they chew in the bark. The larvae bore tunnels in the wood making a loud scraping noise that gave rise to the sawyer name. The life cycle takes two years. The young larvae feed on the inner bark and work their way in to the heartwood, then turn and leave a U-shaped tunnel as they make their way back near the surface. Full grown larvae reach two inches or more in length before they pupate.

Finally, the adult beetle chews its way out of the tunnel leaving a hole of up to half an inch in diameter. The beetle is darkish gray and with mottled black and pale gray markings. Warren’s beetle was one and a half inches long and each antenna was three inches. It was a male as determined by length of antennae. I took it home to photograph it and when it flew away I could clearly see both pairs of wings – like a tiny biplane.

Sources: Borror and DeLong’s Introduction to the Study of Insects; Caterpillars of Eastern North America, David L. Wagner; Insects, Their Natural History and Diversity, Stephen A. Marshall; Center for Reptile and Amphibian Conservation and Management at http://herpcenter.ipfw.edu; NY Forest Owner, issue May/Jjune 1994. ∆


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