Frank Krell, PhD

Dr. Frank Krell works on the taxonomy, natural history, and ecology of living and fossil scarab beetles in the Rocky Mountain region and also worldwide. This large group of beetles contains many beneficial species, such as pollinators, dung and carrion feeders, and also important pest species (leaf and root feeders).

Explore More


View All


Bison Beetle Project

According to Dr. Frank Krell of the Denver Museum of Nature & Science, "There is a lot of poop on the plains." And he would know. Dr. Krell studies dung beetles, tiny critters that recycle animal dung on the Great Plains.

"Dung is concentrated fertilizer on top of soil," Dr. Krell said, "but the nutrients do not get into the soil without dung recyclers -- mainly dung beetles."

Dung beetles especially like bison dung. Dung beetle populations were likely abundant and diverse on the Great Plains when bison flourished 200 years ago. But as bison began to disappear, so did their tiny dung beetle partners. This could pose a huge problem.

"If you have only a few species fulfilling a role in the ecosystem and they can't survive, the whole system breaks down," Dr. Krell said.

Through the Bison Beetle Project, Dr. Krell studies whether or not the reintroduction of bison will help reestablish native dung beetle populations. "We want to find out if the poor dung beetle fauna we have will regenerate with time," Dr. Krell said. "It could be that we destroyed the dung beetle fauna so effectively that it won't regenerate."

The project is a collaboration with the Plains Conservation Center (PCC). Once a month from May to September, Dr. Krell collects bison and cow dung from the PCC Bijou Creek site, about 40 miles east of Denver, and nearby Keen Ranch.

"We want to find out whether it helps to have bison in the area or not," Dr. Krell said.

Dung from both sites is transported to the Museum in buckets, which are then filled with water to extract the beetles. Dr. Krell identifies and evaluates the extracted beetles, looking especially at the differences between fauna found on bison and cow dung. Dung beetles generally prefer bison dung.

"Dung beetles like cattle dung if cattle are grass-fed and not medicated," Dr. Krell said, "However, medicated, partially corn fed cattle produced less suitable dung. It is often toxic to the dung beetle."

It is still unclear, however, whether or not the reintroduction of bison will regenerate native dung beetle populations. Dr. Krell will collect data for at least 10 years to find an answer.

Colorado Scarab Survey

"We are in the midst of a biodiversity crisis-species just die off and we don't really know what it means for us," said Dr. Frank Krell of the Denver Museum of Nature & Science."We need to be able to identify species that affect us in order to deal with them. To preserve or fight a species, we need to know about them."

Dr. Krell studies scarab beetles, a large superfamily of beetles that includes diverse groups like stag beetles, dung beetles, and June bugs. The last scientific catalog of Colorado scarabs was published in 1902. The number of known scarab species in the state has more than doubled since that time. Through the Colorado Scarab Survey, Dr. Krell will collect and document the varied scarab species of Colorado.

"The beetle fauna of the Ivory Coast is probably better known than the beetle fauna of Colorado," Dr. Krell said. "I want to know what's in our state."

With the help of colleagues and volunteers, thousands of scarab specimens have been collected across Colorado. Dr. Krell documented more than 200 different species in a catalog published in 2010, and he expects to find up to 300 scarab species.

After collecting is complete, Dr. Krell will publish an illustrated monograph of Colorado scarab beetles. The book will include information on their distribution, morphology, biology, and ecology, as well as keys for their identification.

"This project involves extensive research in numerous regional and national collections, and repeated collecting in all 64 Colorado counties," Dr. Krell said. "The book will certainly not be completed before 2020."

Fossil Scarab Beetles

"It's like looking at an organism of another planet," Dr. Frank Krell said, describing a fossil scarab beetle incased in amber. "It's just fascinating to see how animals looked millions of years ago."

Scarabs-beetles of the superfamily Scarabaeidae-roamed Earth with dinosaurs. The oldest known fossil scarab beetle is from the Jurassic, but scarab beetles are still around today. Dr. Krell of the Denver Museum of Nature & Science studies fossil scarabs of different ages to find new species and develop ideas about how the beetles evolved through time.

"Scarabs are small-smaller than dinosaurs-so people are not as fascinated," Dr. Krell said. "But scarabs are wonderful. If you analyze all of the little parts, you can reconstruct how they evolved."

Because scarabs have been around for millions of years, they provide an excellent study of evolutionary biology. But Dr. Krell says his research is a small piece of the puzzle. "As scientists, we have to focus on manageable pieces of diversity. Scarabs are just one of those pieces."

Though scarab beetles are widely overlooked today, they symbolized hope and the restoration of life in ancient Egypt. This is likely because of their important ecological role. Dung beetles-one group of scarabs-break down dung and return the nutrients inside to soil, making the nutrients available to other living organisms.

Dr. Krell has reviewed more than 500 fossil scarabs and about 40 different species. Many of these specimens come from the Eocene Messel Formation in Germany, but Dr. Krell works with institutions around the world. Dr. Krell recently described new fossil species from China and Tanzania, and is currently working on material from the Baltic region, Lebanon, Myanmar, Messel, and the Morrison Formation in Colorado.

How Human Land Use Affects Dung Beetle Communities

Humans influence natural habitats around the world. Dung beetles are a species-rich group, sensitive to habitat changes. They also play a vital role in maintaining soil fertility by recycling dung. Dr. Frank Krell of the Denver Museum of Nature & Science explores how human land use affects dung beetle communities from Africa to Colorado.

Much of the team's research has been conducted in developing communities in Africa. "We want to find out how [development and population growth] is reflected in the dung beetle fauna in the area," Dr. Krell said. "We studied the influence of pasture, fire, urbanization in grasslands, and agriculture and logging in forest areas in Ivory Coast and Kenya."

During this fieldwork, the team discovered that minor environmental changes are enough to affect some African dung beetle species. Grass height, for example, can change the amount of sunlight that enters a habitat, which can affect temperature and other vegetation. Some species cannot adapt to these changes.

The team has also studied human impact on dung beetles in areas of Colorado. According to Dr. Krell, even minimally developed areas-such as ranchlands-can become inhospitable for dung beetle populations.

"If anything disturbs the environment, there are at least a few species that will react," Dr. Krell said. "If you look at the plains, there are hardly any entirely natural areas anymore, and the dung beetle fauna is very much reduced."

Although fieldwork for the project in Africa was completed in 2004, Dr. Krell's team is still actively evaluating the data provided by more than 500,000 specimens. "We have plenty of work to do," Dr. Krell said.

Taxonomy of African Dung Beetles

Dr. Frank Krell of the Denver Museum of Nature & Science began research on African dung beetles more than 10 years ago through his Human Land Use and Dung Beetles project. While conducting fieldwork in Ivory Coast and Kenya, he discovered several new dung beetle species. This was not surprising to Dr. Krell, however, who says that tropical Africa is a dung beetle "hot spot."

"If you work in an area that is species-rich, you will find new species," Dr. Krell said, noting that tropical Africa harbors many undiscovered dung beetle species. Dr. Krell is one of just a few scientists qualified to classify these new species.

Using museum collections and his library of about 15,000 scientific papers, Dr. Krell names and describes new dung beetle species. It is tedious work. "You have to go through the hundreds of papers that might have already identified that species," Dr. Krell said.

Some of the new species described by Dr. Krell were actually collected previously but misidentified as existing species. "New species are not necessarily rare-they just haven't been identified correctly," Dr. Krell said. "We are a little bit behind in the knowledge of our fauna."

Since his initial fieldwork, Dr. Krell has teamed up with Association Catharsius, a group of French-speaking scientists who study the dung beetles of West Africa. Association Catharsius will produce a complete monograph of the fauna, a task that has never before been completed.


Scientists across the globe have established well over 1 million scientific animal names. Yet, there is no official registry for these names. "They are scattered over hundreds of thousands of publications," said Dr. Frank Krell of the Denver Museum of Nature & Science.

Dr. Krell is chair of the ZooBank Committee of the International Commission on Zoological Nomenclature (ICZN). The ICZN develops rules and regulations on zoological nomenclature (the naming of animals)-but the actual naming is carried out by individual scientists.

Currently, scientists must conduct extensive research to ensure that any "new species" they discover has not been named previously. "It could be in a little journal in Kazakhstan," Dr. Krell said. "You might not find it."

In 2005, the ICZN began developing ZooBank, the first authoritative online database of zoological names. Once complete, scientists will likely be required to enter all new animal names into the database. This regulation will minimize the background research scientists must conduct before naming a new species.

"We want to facilitate zoological and taxonomical work by providing a central database," Dr. Krell said.

A prototype of the database is currently undergoing testing, but according to Dr. Krell, there is still a lot of work to do. Dr. Krell hopes to make the database more accessible for users in the near future. The committee, however, must establish strict policies and procedures for the registration of names.

"We don't want to rule the zoological community; we want to serve needs," Dr. Krell said. "But with millions of names you have to establish a system that maintains stability and avoids chaos."

The database might take a generation to complete, Dr. Krell said.


Hope for Coral Reefs

The lead scientist for coral reef conservation for The Nature Conservancy, Stephanie Wear will discuss new approaches to solving the coral reef crisis.
Image credit: Coral Reefs in Palau ©Ian Shive

The Truth About Spiders

In this Science Bite, Museum scientist Paula Cushing explains why spiders should be known as the good guys and not the bad guys.

Invaders Everywhere

In this Science Bite, Museum scientist John Demboski talks about introduced species and how they have become a part of our daily lives.

2001 Colorado Blvd
Denver, CO 80205

Open daily
9am - 5pm
Closed Christmas
^ Back to Top