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Types of Insects in Illinois

Insects can be found virtually everywhere. Part of the larger group of animals called arthropods (animals with skeletons on the exteriors of their bodies), insects are identified by their three three distinct body parts: thorax, abdomen and head. Illinois is home to over 17,000 species of insects, including 4,000 different types of flies, 5,000 kinds of beetles and 2,000 types of butterflies and moths.

Buttterflies and Moths
- The cecropia moth makes its home in Illinois.
  
  Illinois' state insect is the monarch butterfly. This insect, from the group Lepidoptera, is easily identified by its bright orange and black wings. It is about 2 inches long with a wingspan between 3-1/2 and 5 inches. Monarch butterflies are usually found in Illinois from May to October and lay their eggs on milkweed plants. Another insect from this group is the cecropia moth. This moth is the largest insect in Illinois and has a wingspan of about 6 inches.
Pests
- Not all insects are viewed as beneficial by humans. In Illinois, one less-attractive species is the housefly, which has a lifespan of about 29 days. In that short time, a female can lay up to 2,000 eggs. Mosquitoes are also common in Illinois. The annoying buzz of the mosquito is caused by the speed of its beating wings, which can move up to 600 times a second. In addition to the discomfort caused by their bites, mosquitoes spread illnesses including encephalitis and West Nile Virus. The itch from a mosquito bite is a result of a chemical in its saliva, which irritates the skin.
Grasshoppers and Praying Mantises
- The praying mantis is another insect found in Illinois.
  
  Two other insects found in Illinois include the grasshopper and the praying mantis. The grasshopper can become a pest in large numbers as it feeds on crops. The grasshopper lives in fields and grassy areas and its green body provides excellent camouflage to protect it from predators.The praying mantis is a carnivore. It eats other insects, even other mantises. The mantis is unique in that it can turn its head a full 180 degrees to look for predators behind it. The female typically eats the male after mating.
Kids' Favorites
- Fireflies are popular insects in Illinois.
  
  Among the most loved insects in Illinois, at least by children, are the ladybug and the firefly. The ladybug is beneficial to humans as it eats aphids and other garden pests. The ladybug is a small beetle known for its colorful hard shell that protects its wings. It congregates with other ladybugs in winter and hibernates in groups of up to 100. The firefly is a summer favorite. It eats other insects, even other fireflies, and pollen. The flashing light from its abdomen is used to warn off predators. The light is also useful in attracting a mate.

Insects & Science