Length: 11-14 mm
The head is black, while the pronotum has orange at the center and the margins. The wing membrane has many veins, a characteristic of the entire Scentless Plant Bug family.
Boisea trivittata feeds on the seeds of a maple species, the Boxelder. It would be a pleasant enough bug, if not for its habit of seeking to enter human habitations for winter shelter. Often as the weather turns cool, houses and outbuildings are covered with the bugs, which are attracted to walls warmed by sunlight. The bugs, fortunately, are not harmful or destructive.
In all but the coldest areas of the United States this species appears to be bivoltine, though in a particularly cold winter the second brood may not survive to maturity. Boxelder Bugs emerge in March and April, feeding on female (pistillate) boxelder trees. They lay clusters of eggs on the trees, or sometimes on buildings, in April and May and once again in June and July. Nymphs are present continually from May until October, while the adults are often scarce or absent in August before the second brood matures.
Despite a 1937 study indicating six instars in this species, Bouldrey and Grimnes (1995) demonstrated that Boisea trivittata has the usual five, with wing pads appearing in the third instar as is typical in Hemiptera. Bouldrey and Grimes also noted that female nymphs were significantly larger than males in all instars.
Given this species' propensity to aggregate, it is interesting that Bouldrey and Grimes' study found that relatively few nymphs survived if they were housed singly. Raised in groups or four or five per container, however, their survival rates were impressively increased.
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