Friday, June 20, 2008
Predacious Stink Bug
Name. This handsome bug must have been named by a “glass half empty” person. It’s true that the bug is a predator and that it belongs to the stink bug family but way before you discover those things you notice its colors and patterns.
Stink bugs, whether predators or not are in the Pentatomidae family which has around 200
different species in North America. The penta- part of the family name refers to the five segments in the antennae. About two thirds of the stink bug species are not predators; they feed on plants. Some are crop and garden pests. The remaining third, the predacious stink bugs, are members of the sub-family Asopina. These bugs compensate for their pesty relatives by preying on other pests. Some are very partial to webworms and tent caterpillars and another is a major predator of the Colorado potato beetle. This particular bug has the scientific name Stiretrus anchorago (also known as the Anchor stink bug) and one of its food preferences is the larvae of the Mexican bean beetle.
When and where found. I found this beetle on June 13 in the wildflower area beside the main parking lot at Great Brook Farm State Park. It was probably hunting for caterpillars and other insects. I didn’t know what it was, at the time, and brought it home for identification. I then set it free in my veggie garden where I hope it develops a fondness for the young caterpillars of the cabbage white butterfly. You can find these bugs from spring up through early fall.
Distinguishing characteristics. The shield shape and the bold markings are the first clues to identification. The colors vary a lot within the species. The dark parts are either dark blue or black but the light parts can be ivory, pink, yellow, orange or red. This one was black, ivory and pink. The legs were an orangish-red. The markings are more or less consistent within the species. There is always the dark central band and the two pale patches one on each side of the thorax and each one containing one to three dark spots.
Sucking and Spitting. True bugs are insects whose mouth parts are adapted for sucking food. The lower lip protrudes and forms a kind of trough which houses the other mouthparts. The two mandibles have developed into long thin blades and are used for cutting. The maxillae form a single tube with two channels, one of which is used for spitting salivary juices into the food and the other is for sucking the liquefied food up. This is quite an elegant arrangement. Consider the human with its single gaping multi-purpose cake-hole which requires the use of other limbs (apple-bobbing aside) for getting the food in.
Sources. Kaufman Field Guide to Insects of North America, Eric A. Eaton and Kenn Kaufman; Insects: Their natural History and Diversity, Stephen A. Marshall; www.BugGuide.net (an excellent web site for insects and for ID assistance). ∆
Submissions: Please feel free to claim this space and write the Biodiversity Corner on any species that occurs in the wild and you have found in Carlisle. Send your submissions to firstname.lastname@example.org.
© 2008 The Carlisle Mosquito