Colorado Entomology Research

In ecosystems with large mammals, dung beetles are a crucial component of the nutrient cycle by being responsible for breaking up dung and reintegrating dung portions into the soil. The dung beetle fauna of the North American plains is currently rather poor, is heavily invaded by European species, and does not seem capable of dung recycling at a significant scale. When 30 to 60 million bison had roamed the Great Plains 200 years ago and produced at least 130 to 260 billion dung pats per year, a more abundant and efficient dung beetle fauna can be assumed. If the presence of bison in an area results in a recovering dung beetle fauna with a higher portion of native species, bison herds can have positive implications on the maintenance of soil quality in rangelands.

We will learn from this eight-year project whether the dung beetle fauna in a prairie area changes after reintroduction of bison. We also hope to determine similarities or differences in the dung beetle fauna of (introduced) cattle and (native) bison. The project had already contributed to a study on the common red-winged Aphodius, which turned out to be two species. The fieldwork for our initial eight-year study ended in 2015, but sorting and identification are still ongoing. 

Our main study sites for the initial eight-year study were situated in Elbert County in Colorado—on the West Bijou property of the Savory Institute (formerly owned by the Plains Conservation Center) and on the adjacent Keen Ranch in Arapahoe County. This research was supported in 2010 by Prairie Biotic Research Inc. and featured in the inaugural issue of the journal of the Plains Conservation Center in November 2011.

In collaboration with the Denver Zoo, we are working on dung beetle samples from Rio Mora National Wildlife Refuge in New Mexico and will study the dung beetles from the bison herds at Genesee Mountain Park and Daniels Park in the Denver area.

Publications

Krell, F.T. 2013. Bison, beetles, and immigrants. Catalyst, Denver Museum of Nature & Science Magazine 17 (June/July 2013): 6–7.

Krell, F.[-T.] & Stephenson, J.T. 2011. Living in dung. Prairie Perspectives Journal, Plains Conservation Center November 2011: 4–5.

Krell, F.-T. 2007. Dung beetle sampling protocols. Denver Museum of Nature & Science Technical Report 2007-6: 11 pp.

Baseline information on the biodiversity of Colorado’s beetle fauna is rather insufficient, considering the ongoing human population growth in the state, habitat degradation, and climate change. In 2007, Frank Krell, PhD, and his team at the Denver Museum of Nature & Science started an ongoing statewide collecting program of scarab beetles in Colorado—the Colorado Scarab Survey. Scarab beetles comprise June bugs, dung beetles, Japanese beetles, and the like. We expect around 300 species to be present in the state. The aim of the survey is to produce a monograph of Colorado scarabs with keys, illustrations, natural history information, and distribution maps for all species, complemented by regular updates on this web page. An initial published compilation of the scattered literature records on the Colorado scarab fauna will serve as the baseline information for the survey.

Publications

Krell, F.-T., Knight, J.B., Hammon, R., Wheeler, P., Roberts, J.J. & Eckberg, J.R. 2015. Northern range extension of the figeater beetle, Cotinis mutabilis (Scarabaeidae: Cetoniinae), into Nevada, Utah, and Colorado. Western North American Naturalist 75 (1): 8–13. DOI: 10.3398/064.075.0103

Miraldo, A., Krell, F.-T., Smalén, M., Angus, R.B. & Roslin, T. 2014. Making the cryptic visible - resolving the species complex of Aphodius fimetarius (Linnaeus, 1758) and Aphodius pedellus (de Geer, 1774) (Coleoptera: Scarabaeidae) by three complementary methods. Systematic Entomology 39: 531–547. DOI: 10.1111/syen.12079

Krell, F.-T. 2010. Catalogue of Colorado scarab and stag beetles (Coleoptera: Scarabaeoidea), based on literature records. Denver Museum of Nature & Science Technical Report 2010-4: 84 pp.

Many of you might have seen pretty, shiny brown and metallic beetles in yards and parks, feeding in numbers on roses, Virginia creeper, or almost any other plant you can think of. These are Japanese beetles (Popillia japonica), a species of scarab beetle accidentally introduced to the eastern United States over 100 years ago. In the early 1990s, they arrived in the Denver area and for the last few years became a serious pest of ornamental plants and lawns. The adult beetles feed on hundreds of species of plants, preferring roses and vines. The larvae feed on the roots of well-watered lawn.

The Museum is trying to determine how far the Japanese beetle has spread in Colorado and to compile a distribution map of all the records we can obtain. For this, we sought your help in the previous two years and received hundreds of samples delivered by many citizen scientists of all ages. This year we are preparing a report to be published in a scientific journal.

The year 2017 was amazing: 215 citizen scientists brought in 2,235 specimens from Boulder to Pueblo, enabling us to produce a comprehensive distribution map of the beetle for the Denver metro area, which was published by the Denver Post in 2018. In 2018 and 2019, we wanted to see if the beetles invaded areas that were not affected the year before: western Lakewood, Wheat Ridge, Arvada, Commerce City, Thornton, and Broomfield to Loveland. While those areas were much less affected than central and southern Denver Metro, we received several records from citizen scientists. The Japanese beetle is spreading its wings and is likely to invade suburban areas previously unaffected. If you encounter Japanese beetles in areas not represented in the map below, please collect a few and preserve them in a well-sealed vial or bag. The preferred storage is in 70% rubbing alcohol in a tight container.  Attach a note with the following information:

• the location (address) where the beetles were found;
• when they were collected; and
• who collected them.

Thank you again for your invaluable help! This is a project that could not be done without your support.

We will update the online distribution map and our online database with your records soon after I received them.

Publications

Krell, F-T. 2018. Japanese beetles make Colorado home. YourHub (Denver Post) July 12, 2018: 6T+9T.

Theodore Cockerell's Legacy

Change of the beetle fauna of Custer County, Colorado, during the last 130 years.

The English naturalist Theodore Dru Allison Cockerell (1866–1948) came to Westcliffe in Custer County in July 1887 to cure a mild tuberculosis. He resided mainly at and around the Historic Pines Ranch and ended up staying for three years in the Wet Mountain Valley. During this period, he extensively collected and later published the beetle fauna of the area around Westcliffe. This is likely to be the only published comprehensive beetle fauna from Colorado of the 19th century and is a suitable baseline for determining faunal change during the last 130 years. In 2012, we started a collecting program in Custer County to compare the current fauna with Cockerell’s records. Despite the effect of mining and ranching on landscape and associated biota, Custer County’s low human population size and consequently limited development and degradation make this county a model for the study of climate-driven faunal change. We will be collecting in Custer County for the foreseeable future to obtain a comparable data set of the present fauna.

While working with Cockerell’s papers and data, Dr. Krell became interested in the life of this remarkable researcher personality and is currently finalizing a book on Cockerell’s early years, to be published in the Denver Museum of Nature & Science Annals.

T.D.A. Cockerell (1866-1948) was one of the most prolific zoologists of his time, having produced over 3900 scientific papers and notes. For most of his life he was Professor of Zoology at the University of Colorado Boulder. This study explores his formative years, from his childhood and youth in southeast England, to his first voyages to Madeira and a long sojourn in Westcliffe, Colorado, until his first paid position as curator at the Institute of Jamaica in 1891.