Prairie Research Institute

Illinois Natural History Survey

Over 1 million insect species have been described worldwide. Some of these species are vital to our wellbeing, serving as pollinators, recyclers of nutrients, and sources of food for other animals and even some plants. Others are agricultural pests that inflict significant economic damage and vectors of diseases that harm humans, livestock, crops, and wildlife.

Whether conservation or control measures are needed, federal and state agencies require up-to-date information on insect distributions, status, and life history to make informed management goals and decisions. INHS scientists travel across Illinois and beyond collecting these data. They survey insect populations and communities, including those that pose a threat to agriculture and public health; conduct ecological studies; describe new insect species; and untangle evolutionary relationships among insect groups and species.

Surveys and ecological work

INHS entomologists use conventional methods to survey and study aquatic and terrestrial insect species, gleaning information on the insects’ distribution, status, and life history traits.

They also investigate novel ways of collecting data on insect populations and communities. For instance, INHS Collaborative Ecological Genetics Lab researchers are examining the feasibility of using environmental DNA (eDNA)—residual DNA left behind as organisms interact with their environment—to detect insect species.

Aquatic macroinvertebrates

Aquatic macroinvertebrates are important food sources and mediators of energy flow and nutrient cycling in stream environments. They are also immensely useful as indicators of water and habitat quality and quantity, in part because they exhibit a wide range of tolerance to pollution.

The health of most Midwestern streams and rivers has been compromised by pollution, habitat degradation, and overloading with nutrients and fine sediment. INHS scientists survey aquatic communities, including macroinvertebrates, and use these data to assess the impairment level and restoration potential of waterways—the information state and federal agencies need to manage waterway issues and help prevent further quality declines.

For example, INHS entomologists with the Urban Biotic Assessment Program (UBAP) work with the Illinois State Toll Highway Authority to document the health of streams and rivers in the urban to rural gradient that the Tollway network covers.

INHS scientists have studied Jordan Creek since the 1950s, amassing a well-developed database on the small stream’s historical invertebrate and fish populations and water chemistry. Since 2020, INHS Stream Ecology Lab scientists have continued on with this tradition, monitoring Jordan Creek’s macroinvertebrate and fish communities and stream habitat.

INHS Stream Ecology Lab scientists also study the Illinois Conservation Reserve Enhancement Program (CREP)’s impact on macroinvertebrate, fish, and mussel populations; water quality; and in-stream habitat quality by conducting annual monitoring throughout the Illinois and Kaskaskia river basins—watersheds that are eligible for CREP enrollment. CREP aims to improve water quality and enhance wildlife habitat by offering private landowners financial incentives to take highly erosive agricultural lands out of production.

Stoneflies, mayflies, and caddisflies

INHS scientist Ed DeWalt specializes in the study of stoneflies, mayflies, and caddisflies—three orders of aquatic insects that are commonly used as indicators of water quality. DeWalt is using a combination of museum specimen records and contemporary sampling to reconstruct the pre-European settlement ranges of Midwestern stonefly species, studying the conservation status of state watchlisted aquatic insects and examining the role that human disturbance and natural factors have played in Illinois’ declining stonefly populations. Recent work by students documented the conservation status of stoneflies in Indiana, produced a rigorous phylogeny of North American stoneflies, and described a new family of stoneflies.

INHS Stream Ecology Lab scientists are using historical and contemporary distributions of macroinvertebrates (i.e., mayflies, stoneflies, caddisflies), fishes, and freshwater mussels in Illinois’ wadeable streams to re-characterize the biological significance of all streams and rivers in the state. These updates will help ensure that Illinois’ aquatic systems and the services they provide are restored from impaired conditions and conserved using well-informed management plans.

Odonates (dragonflies and damselflies)

Odonates are prized as good indicators of water quality and voracious predators that consume lots of mosquitos and other pests. These useful insects are focal species within the Wetlands Campaign of the Illinois Wildlife Action Plan.

Urban Biotic Assessment Program (UBAP) scientists are surveying and studying the habitat preferences of two listed dragonfly species within the greater Illinois Tollway region.

  • Illinois state-threatened elfin skimmer: UBAP scientists are visiting calcareous fens within the Tollway corridor, re-surveying historical locations where the elfin skimmer has been documented along with nearby suitable habitat to determine the species’ current distribution. INHS scientists are also testing the feasibility of environmental DNA (eDNA) to determine the presence of this diminutive, cryptic species due to the difficulty in detecting it using traditional visual surveys.
  • Federally endangered Hine’s emerald dragonfly: INHS scientists are developing a species distribution model for the Hine’s emerald dragonfly using characteristics (e.g., soils, climate, geology) of its known localities to predict new sites or habitats where it could be found. INHS researchers are also building a detection model summarizing the effort and ideal environmental conditions biologists and land managers require to confidently determine whether or not the Hine’s Emerald Dragonfly is present at a site.

INHS Odonata specialist Jason Bried also is doing targeted surveys for other odonates of state and regional conservation concern and is helping with odonate status assessments and expanding the statewide volunteer network for monitoring odonates.


Bumble bees are important pollinators, but their numbers are declining due to habitat loss, diseases, pesticides, and other factors. INHS researchers travel to sites around Illinois surveying native bumble bees, with a focus on species in greatest conservation need. By studying the insects’ behavior and habitats, the scientists hope to determine ways to stop population declines and inform management efforts.

Urban Biotic Assessment Program (UBAP) scientists have been surveying for the federally endangered rusty patched bumble bee at sites near and within the Illinois Tollway corridor. Once active in Illinois, this rare bumble bee is now on the brink of extinction. The team’s work helps to ensure that the Tollway can make decisions about the location and timing of construction and maintenance projects to avoid negatively impacting it.

Butterflies and moths

Monarch butterfly

Conservation efforts for monarch butterflies have encouraged the widespread planting of milkweeds—monarch caterpillars’ sole food source—but it’s unclear how the landscape influences the success of such plantings. INHS scientist David Zaya is leading a community science research project examining how monarch butterfly egg laying and caterpillar growth respond to different garden and landscape variables through the University of Illinois’ I-Pollinate program. Data from the project will help us better understand and use gardens to contribute to the conservation and resurgence of monarchs and other pollinators.

Rattlesnake-master stem borer moth

INHS researchers are also assessing populations and examining the genetic diversity and structure of the rattlesnake-master stem borer moth, a state-endangered species threatened by habitat loss, pesticide use, and habitat fragmentation.


INHS researcher Katie Dana has been surveying cicadas in areas across Illinois—from prairies to urban parks—since 2015 to better understand their diversity, distribution, and habitat preferences. Her work helps to inform state conservation efforts for these charismatic insects, which can serve as an important food source for insectivorous birds, snakes, and spiders.

Plant-insect interactions

INHS scientist Brenda Molano-Flores and members of the Molano-Flores Plant Ecology Lab document insect pollinator communities for rare, threatened, and endangered plants in order to examine how pollinators affect the plants’ reproductive success. Recent work has included conducting pollinator observations for three carnivorous butterwort (Pinguicula) species in the Florida Panhandle and the Kaibab bladderpod (Physaria kaibabensis) in the Kaibab Plateau of Arizona.

Molano-Flores is also working with scientists from the INHS Collaborative Ecological Genetics Lab to examine how environmental DNA (eDNA) left behind on flowers could be leveraged to document pollinator communities, as conventional methods for determining plant pollinator communities can be time consuming and expensive.

Taxonomy and systematics

INHS scientists discover, name, and classify species (taxonomy) and investigate the evolutionary relationships among groups and species (systematics) of insects from around the world.

For example, a research team led by INHS scientists Kevin Johnson and Christopher Dietrich recently used a vast molecular and morphological dataset to tease out the family relationships and evolutionary history of hemipteroid insects. Composed of over 120,000 described species, Hemiptera includes true bugs, leafhoppers, aphids, thrips, and parasitic lice, and contains many crop pests and human disease vectors.

Read more about INHS taxonomy and systematics work.

Leafhoppers and treehoppers

The Dietrich Leafhopper Lab, led by Illinois State Entomologist Christopher Dietrich, focuses on documenting global diversity of leafhoppers and related insects, reconstructing their evolutionary relationships, providing user-friendly tools for species identification, assessing the conservation status of insects in threatened ecosystems, and documenting associations between leafhoppers and plant pathogens of potential agricultural importance.

Grasshoppers, crickets, katydids, and relatives

Using fossil specimens and some modern taxa, INHS paleontologist Sam Heads studies the evolutionary history of Orthoptera (grasshoppers and crickets) and examines the group’s morphological character acquisition and evolution over time. Heads has also described and named many new species from basal orthopteran groups, including Elcanoidea (grasshopper-like orthopterans), Tridactyloidea (pygmy mole crickets and ripiterygids), Tetrigoidea (pygmy grasshoppers), the acridomorph superfamilies Eumastacoidea (clown grasshoppers, morabids, and allies) and Proscopioidea (stick and horsehead grasshoppers), Grylloidea, and Tettigonioidea.


Tommy McElrath studies the taxonomy and systematics of the beetle superfamily Cucujoidea, specializing on the minute clubbed beetles (family Monotomidae) and the flat bark beetles (families Silvanidae, Laemophloeidae, and Cucujidae). He is collaboratively building the first worldwide digital catalogue of the superfamily as part of the Cucujoidea World Catalog. In addition, he is developing identification resources for the group, including new dichotomous keys for many families in North America.

Agricultural pest management

Agricultural insect pests have always caused problems for Illinois growers. Some pest species have affected crop production for the past century, but newly arrived pests, new pest behaviors, and changes in management tactics demand continued vigilance, research, and action to maintain sustainable and profitable crop production in Illinois.

The Illinois Cooperative Agricultural Pest Survey (CAPS) program at INHS focuses on the early detection of invasive pests through surveys of both the pathways of potential introduction and the commodities they can impact. The CAPS program works with the U.S. Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine and the Illinois Department of Agriculture. If pests are detected, surveys are then conducted to determine the extent of the area occupied by the pest. Depending on the pest, eradication plans are put in place.

Corn rootworm

Corn rootworm beetles are the most devastating pests of America’s most valuable crop, corn. Annual yield losses and management costs of western corn rootworms (WCR) and the closely related northern corn rootworm (NCR) may exceed $2 billion across the U.S. Corn Belt. These agricultural pests have evolved resistance to insecticides, annual crop rotation, and every rootworm-specific bacterial toxin engineered into transgenic “Bt” corn hybrids.

INHS insect behaviorist Joseph Spencer has studied the ecology, behavior, biology, and resistance of WCR for over 25 years, making progress in understanding the role of WCR behavior in pest adaptations to annual crop rotation and Bt corn hybrids. From changes in female egg-laying affinity for cornfields to patterns of intra- and interfield movement in Bt corn and startling adaptations of the WCR microbiota and gene expression in feeding individuals, “paying attention” to what WCR are actually doing is a foundation for understanding.  Current work studying the status of WCR and NCR resistance to the toxins expressed in Bt corn hybrids as well as efforts to improve adoption of integrated pest management-based controls are aimed at providing sustainable tactics that work for farmers. Resistance has long been a driver of innovation in rootworm management. Our hope is that studying mechanisms of adaptive rootworm behavior will reveal new vulnerabilities that may make our tactics more durable and effective.

Pest degree calculators

INHS scientist Kelly Estes and Illinois State Water Survey researchers recently updated two pest degree day calculators for commodity and specialty crop growers in Illinois, featuring seven-day weather forecasts, graphs, and insect emergence maps to track accumulated degree days and light for the most notorious pests, including corn flea beetle and the prediction of potential Stewart’s Wilt severity, Japanese beetle emergence, and brown marmorated stinkbug activity. These tools help farmers plan pest management efforts and use pest control more efficiently. Because temperature controls the rate that insects develop, the new degree day calculators use data from the Water Survey’s network of weather monitoring stations so growers can calculate degree days accumulated in their region of the state for specific pests, such as the codling moth, spotted wing drosophila, corn rootworm, or emerald ash borer.

Medical entomology

The INHS Medical Entomology Lab conducts statewide monitoring and surveillance of mosquitoes (and ticks) that can be vectors for diseases that infect both people and animals. Their applied field and lab research on mosquito vectors is aimed at more effectively detecting, preventing, and controlling diseases such as Zika and West Nile.

Recent work has focused on detecting the distribution and abundance of the Asian tiger mosquito, which can transmit diseases like chikungunya and dengue fever. The research team is also conducting studies on:

  • insecticide resistance in Illinois mosquito populations and the genetic mechanisms behind it;
  • mosquito foraging behavior to inform development and optimization of novel vector control tools;
  • effects of the resource landscape on mosquito communities and arbovirus (e.g., West Nile) transmission; and
  • mosquito behavior and ecology, physiology, and immunology in the lab to better understand how resources in the landscape and climate change can affect vector-borne pathogen transmission.

Read more about INHS infectious disease research.

Insect collection

The INHS Insect Collection, which includes approximately 7 million prepared specimens as well as non-insect arthropods (e.g., arachnids and myriapods) and miscellaneous invertebrates (bryozoans), is one of the largest and oldest entomological collections in North America. Specimen holdings emphasize the upper midwestern United States, but are global in scope for certain groups, particularly Coleoptera, Collembola, Diptera, Hemiptera (Auchenorrhyncha), Hymenoptera (Apoidea), Lepidoptera, Plecoptera, Psocodea (Psocoptera and Phthiraptera), Thysanoptera, and Trichoptera. The collection contains significant historical holdings from Illinois dating to the mid-1800s, including at least 3,079 primary and over 10,000 secondary type specimens.

Read more about all INHS biological collections.

Fossil insect collection

Curated by INHS paleontologist Sam Heads, the Prairie Research Institute Center for Paleontology houses a rapidly growing collection of fossil insects from across the globe. Notable compression fossil holdings include:

  • thousands of insect specimens preserved in paper shale from the 23 million to 33 million-year-old Renova Formation of Montana;
  • approximately 500 exceptionally preserved insect fossils from the Crato Formation, a 120 million to 115 million-year-old limestone deposit in northeastern Brazil; and
  • a small collection of insect specimens preserved in oil shale from the 49.7 million to 50.7 million-year-old Green River Formation in western Colorado.

The Center for Paleontology is also home to the Milton Sanderson Dominican Amber Collection—the oldest and perhaps largest unbiased collection of early Miocene (16 million to 18 million-year-old) Dominican amber in the world. INHS researchers and volunteers are gradually screening the collection’s 160 pounds (approximately 140,000 pieces) of amber for insects and other inclusions. As fossil-containing pieces are identified, they are embedded in a synthetic resin to protect them from damage through oxidation.

INHS scientists and volunteers continually work to curate, database, image, and describe new species from the Center for Paleontology’s holdings in order to gain new insights about what Earth was like millions of years in the past.

Read more about all INHS biological collections.

Office of the State Entomologist

The Illinois State Entomologist serves as an authoritative spokesperson on matters related to insects or other arthropods of Illinois and is a source of objective information on insects for policymakers and the public. Current Illinois State Entomologist Christopher Dietrich has more than 30 years of entomological research experience, has conducted field work in 17 countries, and has published more than 200 refereed scientific papers. He is broadly interested in insect biodiversity, evolution, classification and identification and is a world authority on leafhoppers and treehoppers.


Butterflies of Illinois: A Field Guide

Geared toward butterfly enthusiasts and experts alike, Butterflies of Illinois: A Field Guide is a portable, easy-to-use guide rich with descriptions, field photography, and life-sized specimen photos of all the state’s native species. It also includes identification quick guides depicting the tops and undersides of all butterfly species; scientific information and photos that explain life cycles, habitats, and ecology; range maps; flight period charts; key characteristics relevant to field identification; descriptions of rarely seen butterflies and irregular visitors from nearby states; and supplemental information on various species, including collection records and unusual sightings. The guide is available for purchase from the University of Illinois Press.

Other publications

Many INHS Bulletins and monographs are out of print but remain the best available resources for identifying species in these particular groups. These and other INHS publications are freely available in the University’s IDEALS repository.

Species lists, databases, and distributions