Beetles of Wisconsin
Wisconsin is home to hundreds of beetle species. Some of these are beneficial, while others are considered by farmers and gardeners to be pests. The tableau of beetles in the state is varied and complex. It represents species of many colors and sizes as well as those with unique, interesting features.
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Size and Appearance
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Wisconsin beetles vary greatly in shape, size and appearance. Some are very small, like the striped and spotted cucumber beetles, which grow to be only 1/5 of an inch long. Tiger beetles and blister beetles both grow to an average of one inch, while stag beetles can grow to almost an inch and a half. Color, too, varies among beetles. Cucumber beetles are light greenish-yellow with black spots or stripes, depending on the species. Asian lady beetles are red with black spots. Tiger beetles are black with orange legs and stag beetles are a dark red or brown color all over.
Activity
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There is also variety in the periods of activity among Wisconsin beetles. Tiger beetles, for instance, are mainly seen in late summer, though they are active between April and October. They are nocturnal beetles, just like the stag beetle, and stay under cover during the day. Striped cucumber beetles start becoming active in mid to late May and hibernate during the winter. Spotted cucumber beetles, however, do not overwinter and instead migrate north in early to mid-July. Blister beetles are latecomers, emerging from the ground, where they pupate, in late June or July, often in large numbers.
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Unique Features
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Various species of beetles in Wisconsin have unique features. The stag beetle, for instance, has a memorable physical aspect that sets it apart from other beetles. These are the large mandibles that give it an antagonistic appearance. In males, these mandibles can be as large as the beetle's head, while the female has a shorter version. Males use them to fight for mating rights. The blister beetle's uniqueness lies in its development. Individuals go through life stages that no other beetles do, including five to seven instars as larvae, each with distinct physical changes.
Beneficial and Detrimental Eating Habits
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Depending on what a beetle eats, it may or may not be considered a pest species. Stag beetles are not considered pests because they mainly feed on sap, not crops. Cucumber beetles, on the other hand, are considered pests, especially stripe cucumber beetles. They feed on crops that include cucumbers, watermelon, muskmelon, squash and pumpkin. Larvae feed on roots and stems, stunting the growth of these crops, while adults feed on stems, leaves and fruit. Blister beetle adults, also pests, feed on ornamental foliage and a variety of crops. Their larvae, however, are beneficial because they feed on grasshopper eggs. Asian lady beetles are also beneficial because they feed on other pest insect species.
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References
- University of Wisconsin; Blister Beetle Larvae; Susan Mahr
- Insect Identification; Stag Beetle; 2011
- National Prairie Wildlife Research Center; Tiger Beetles of Wisconsin; 2006
- Wisconsin Council of Invasive Species; Multicolored Asian Lady Beetles in Wisconsin: Foe or Friend?; Jim Doyle; October 2005
- University of Wisconsin; Cucumber Beetles; Karen Delahaut; August 2010
Resources
- Photo Credit Brand X Pictures/Brand X Pictures/Getty Images
