Global Entomology Research

Scarab and stag beetles (Coleoptera: Scarabaeoidea) are particularly hard-shelled beetles. They appeared in the fossil record as early as the Jurassic Period and evolved into one of the largest beetle superfamilies with over 35,000 extant species. While some scarabaeoids are among the largest extant and fossil beetles, such as goliath and rhinoceros beetles, most of them are less than one centimeter long. Sufficiently detailed preservation of such small beetles requires either an extremely fine-grained sediment or embedment in natural resin. The photo shows the holotype of Calcitoryctes magnificus Krell, 2001, a three-dimensionally preserved rhinoceros beetle from the Piocene of Laetoli, Tanzania.

Our current research focuses on fossils from lagerstätten with particularly high-quality insect preservation, such as amber and the oil shales of the Messel Formation (Eocene). Amber provides detailed three-dimensional preservation. In many of the Messel compression fossils, the original structural color is preserved. Both kinds of fossils provide a unique window into the past and help in reconstructing evolution and phylogeny of our study groups.

Publications

Chin, K. & Krell, F.-T. 2019. The evolution of complex coprophagous behavior: ichnofossil evidence of brood provisioning and dung relocation by dung beetles in the Late Cretaceous. 11th North American Paleontological Convention, University of California, Riverside, June 23–27, 2019. PaleoBios 36 (Suppl. 1): 100‒101.

Krell, F.-T. 2019. High quality insect preservation—fossils in amber (Baltic, Lebanon, Myanmar) and from the Messel Formation (Eocene, Germany), with emphasis on scarab beetles. Lagerstätten. Exceptional Preservation. Extraordinary Fossils. Western Interior Paleontological Society 11th Founders Symposium, March 23‒24, 2019, Lowry Conference Center, Aurora, Colorado, Program & Abstracts, vol. 11: 39‒42.

Kirejtshuk, A.G., Ponomarenko, A.G., Kurochkin, A.S., Alexeev, A.V., Gratshev V.G., Solodovnikov, A.Y., Krell, F.-T. & Soriano, C. 2019. The beetle (Coleoptera) fauna of the Insect Limestone (Late Eocene), Isle of Wight, southern England. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 110: 405–492. DOI: 10.1017/S1755691018000865

Tarasov, S., Vaz-de-Mello, F., Krell, F.-T. & Dimitrov, D. 2016. A review and phylogeny of scarabaeine dung beetle fossils (Coleoptera: Scarabaeidae: Scarabaeinae), with the description and two Canthochilum species from Dominican amber. PeerJ 4: e1988, 35 pp. DOI: 10.7717/peerj.1988

Krell, F.-T. 2014. Pleistocene Dung Beetles from MIS 5 at Ziegler Reservoir, Snowmass Village, Colorado (Coleoptera: Scarabaeidae: Aphodiinae: Aphodiini and Aegialiini). Denver Museum of Nature & Science Annals 5: 1–12. DOI: 10.55485/INYL3767

Krell, F.-T. & Schawaller, W. 2011. Beetles (Insecta: Coleoptera). Pp. 535–548 in: T. Harrison (ed.): Paleontology and Geology of Laetoli: Volume 2: Fossil Hominines and the Associated Fauna. Dordrecht: Springer. DOI: 10.1007/978-90-481-9962-4_19

Bai, M., Krell, F.T., Ren, D. & Yang, X. 2010. A new, well-preserved species of Glaresidae (Coleoptera: Scarabaeoidea) from the Jehol Biota of China. Acta Geologica Sinica (English Edition) 84 (4): 676-679. DOI: 10.1111/j.1755-6724.2010.00229.x

Krell, F.-T. 2007. Catalogue of fossil Scarabaeoidea (Coleoptera: Polyphaga) of the Mesozoic and Tertiary – Version 2007 –. Denver Museum of Nature & Science Technical Report 2007-8: 79 pp.

In our times of a biodiversity crisis, when abundance and species numbers decline worldwide, documenting the species we are sharing the planet with becomes an increasingly important and urgent task. The science of describing and naming new and reviewing already known species is called taxonomy. Our senior curator of entomology, Frank T. Krell, PhD, is a taxonomist and expert of the beetle group Scarabaeoidea, the scarab beetles in the widest sense, comprising June bugs, stag beetles, dung beetles, flower chafers, rhinoceros beetles, and the like. About 35,0000 species of scarabaeoid beetles have been described in the scientific literature, a few of them by Dr. Krell. But we can expect probably an equally high number still to be discovered, be it in Colorado or in the forests of the Amazon. Dr. Krell is actively engaged in species discovery and is currently preparing descriptions of new species of dung beetles from West and Southern Africa. Discovering a species nobody has ever seen or recognized before is one of the most exciting moments in the life of a taxonomist.

Publications

Ahrens, D., Ahyong, S.T., Ballerio, A., Barclay, M.V.L., Eberle, J., Espeland, E., Huber, B.A., Mengual, X., Pacheco, T.L., Peters, R.S., Rulik, B., Vaz-de-Mello, F., Wesener, T. & Krell, F.-T. 2021. Is it time to describe new species without diagnoses? - A comment on Sharkey et al. (2021). Zootaxa 5927: 151–159. DOI: 10.11646/zootaxa.5027.2.1

Krell, F.-T. 2021. Taxonomy and distribution of Orubesa in the Arabian Peninsula and surrounding areas (Coleoptera: Scarabaeoidea). Zoology in the Middle East 67 (4): 332–343. DOI:10.1080/09397140.2021.1957209

Moretto, P., Cosson, B., Krell, F.-T. & Aristophanous, M. 2019. Pollination of Amorphophallus barthlottii and A. abyssinicus subsp. akeassii (Araceae) by dung beetles (Insecta: Coleoptera: Scarabaeoidea). Catharsius 18: 19‒36.

Thomson, S.A., Pyle, R.L., Ahyong, S., Alonso-Zarazaga, M., ...Krell, F.-T., ...Zhou, H.-Z. 2018. Taxonomy based on science is necessary for global conservation. PLOS Biology 16(3): e2005075 (12 pp.). DOI: 10.1371/journal.pbio.2005075

Krell, F.-T. 2018. Zu Verbreitung und Morphologie einiger Onthophagus-Arten der Schweiz (Coleoptera: Scarabaeidae). Alpine Entomology 2: 59–75, 2 supplements. DOI: 10.3897/alpento.2.23345

Krell F.-T. & Marshall, S.A. 2017. New species described from photographs: Yes? No? Sometimes? A fierce debate and a new Declaration of the ICZN. Insect Systematics and Diversity 1 (1): 3–19. DOI: 10.1093/isd/ixx004

Krell, F.-T. & Král, D. 2017. Order Coleoptera, family Scarabaeidae. Subfamily Dynastinae. Arthropod Fauna of the UAE 6: 169–185.

Amorim, D.S., Santos, C.M.D., Krell, F.-T., Dubois, A., Nihei, S.S., Oliveira, O.M.P., Pont, A., Song, H., Verdade, V.K., Fachin, D.A., Klassa, B., Lamas, C.J.E., Oliveira, S.S., Carvalho, C.J.B. de, Mello-Patiu, C.A., Hajdu, E., Couri, M.S., Silva, V.C., Capellari, R.S., Falaschi, R.L., Feitosa, R.M., Prendini, L., Pombal Jr., J.P., Fernández, F., Rocha, R.M., Lattke, J.E., Caramaschi, U., Duarte, M., Marques, A.C., Reis, R.E., Kurina, O., Takiya, D.M., Tavares. M., Fernandes, D.S., Franco, F.L., Cuezzo, F., Paulson, D., Guénard, B., Schlick-Steiner, B.C., Arthofer, W., Steiner, F.M., Fisher, B.L., Johnson, R.A., Delsinne, T.D., Donoso, D.A., Mulieri, P.R., Patitucci, L.D., Carpenter, J.M., Herman, L. & Grimaldi, D. 2016. Timeless standards for species delimitation. Zootaxa 4137 (1): 121–128. DOI: 10.11646/zootaxa.4137.1.94

Krell, F.-T., Klimeš, P., Rocha, L.A., Fikáček, M. & Miller, S.A. 2016. Preserve specimens for reproducibility. Nature 539 (7628): 168. DOI: 10.1038/539168b

Forshage, M. & Krell, F.-T. 2016. Two exotic dynastines collected in Sweden (Coleoptera: Scarabaeidae: Dynastinae). Entomologisk Tidskrift 137 (4): 147–149.

Krell, F.-T. & Breidenbaugh, M. 2016. The mango flower beetle, Protaetia fusca (Herbst), on Wake Island, Western Pacific Ocean (Coleoptera: Scarabaeidae: Cetoniinae)—an accomplished island invasive. Proceedings of the Hawaiian Entomological Society 48: 9–13.

Krell, F.-T. & Theuerkauf, J. 2015. A new species of the endemic genus Hemicyrthus Reiche (Coleoptera: Scarabaeidae: Dynastinae) from New Caledonia, with a revised key. Zootaxa 4048 (2): 281–290. DOI: 10.11646/zootaxa.4048.2.8

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. & Wheeler, Q. 2014. Specimen collection: Plan for the future. Science 344 (6186): 815–816. DOI: 10.1126/science.344.6186.815

Albertoni, F.F., Krell, F.-T., Steiner, J. & Zillikens, A. 2014. Life history and description of larva and pupa of Platyphileurus felscheanus Ohaus 1910, a scarabaeid feeding on bromeliad tissues in Brazil, to be excluded from Phileurini (Coleoptera, Scarabaeidae, Dynastinae). Zookeys 389: 49–76. DOI: 10.3897/zookeys.389.6888

Krell, F.-T. 2013. Pleurophorus caesus new to New Mexico (Coleoptera: Scarabaeidae: Aphodiinae). Entomological News 122 (5): 491–492. DOI: 10.3157/021.122.0512

Krell, F.-T. 2012. An old record of the Japanese beetle, Popillia japonica Newman, from Panama (Coleoptera: Scarabaeidae: Rutelinae). Entomologist's Monthly Magazine 148 (3): 231–233.

Krell, F.-T. & Philips, T.K. 2010. Formicdubius Philips & Scholtz from South Africa, a junior synonym of Haroldius Boucomont, and a survey of the trichomes in the African species (Coleoptera: Scarabaeidae: Onthophagini). ZooKeys 34: 41–48. DOI: 10.3897/zookeys.34.342

Rössner, E. & Krell, F.-T. 2009. Identität und taxonomischer Status von Amphimallon ochraceum (Knoch, 1801) und A. fallenii (Gyllenhal, 1817) sowie weiterer mit A. solstitiale (Linnaeus, 1758) verwandter Taxa (Coleoptera: Scarabaeidae: Melolonthinae). Vernate 27.2008: 221-261.

Motala, S.M. & Krell, F.-T. 2007. A wider range than suspected: new locality for the endemic Mauritian dung beetle Nesosisyphus pygmaeus (Coleoptera: Scarabaeidae). Phelsuma 15: 63-64.

Almost every spot on earth shows signs of human influence, modification, or destruction. Human land use, be it agriculture, forestry, or urbanization, almost always leads to a reduction of the number of species that can persist in such areas. The species-rich dung beetles are suitable for studying the effects of land use because many species react early to changes in vegetation cover, microclimate, or provision of food resources. Since 1995, my teams of students and I have studied the ecology of dung beetles and the influence of human land use on dung beetle communities. In West and East Africa, in Ivory Coast and Kenya, we investigated the effects of agricultural practices, pasture, burning, logging, and urbanization. Our main sites in the Ivory Coast were situated in the Parc National de la Comoé, in the village of Bringakro, and in Abidjan, in collaboration with the Centre Suisse de Recherches Scientifiques and the Université d’Abobo-Adjamé. In Kenya, we worked in and around Kakamega Forest, in collaboration with ICIPE and the National Museums of Kenya. We are not continuing overseas fieldwork at the moment but are busy at the Denver Museum of Nature & Science working on the thousands of samples and hundreds of thousands of specimens collected in Africa. We will continue publishing results in the years to come.

Here in Colorado, our Scarab Survey, launched in 2007, will provide baseline data on the current distribution of scarab beetles and will compile historic data; this will allow us to determine the possible effects of human land use in the past and faunal changes in the future.

For species identification, beetles need to be pinned to or glued on a piece of archival cardboard. Our team of great entomology collection assistant volunteers will likely finish pinning and mounting all of our backlog from the 1990s within a year, when volunteer operations will be resumed. Before the break due to Covid, they were already busy with backlog samples from the land use studies from Bringakro (Ivory Coast), opening the opportunity to evaluate our data at species level. Wonderful work! We cannot wait welcoming our volunteers back.

Publications

Krell, F.-T. & Moon, A.R. 2019. Quick guides: Dung beetles. Current Biology 29 (12): R554‒R555. DOI: 10.1016/j.cub.2019.05.027

Barnes, A.D., Emberson, R.M., Krell, F.-T. & Didham, R.K. 2014. The role of species traits in mediating functional recovery during matrix restoration. PLOS ONE 9(12): e115385 (19 pp.). DOI: 10.1371/journal.pone.0115385

Barnes, A.D., Emberson, R.M., Chapman, H.M., Krell, F.-T. & Didham, R.K. 2014. Matrix habitat restoration alters dung beetle species responses across tropical forest edges. Biological Conservation 170: 28–37. DOI: 10.1016/j.biocon.2013.12.006

Theuerkauf, J., Rouys, S., van Berge Henegouwen, A.L., Krell, F.-T., Mazur, S. & Mühlenberg, M. 2009. Colonisation of forest elephant dung by invertebrates in the Bossematié Forest Reserve, Ivory Coast. Zoological Studies 48 (3): 343–350.