A historic analysis of the classification of Scarabaeoidea is presented. The analysis comprises a historic comparison of the type and number of characters of the genera and their grouping into higher-level taxa. The analysis is divided into three time periods, including a review of 70 publications on scarab systematics (beginning with Linnaeus). The first period (1735–1858) encompasses an era prior to the publication of Darwin's The Origin of Species, and it is, therefore, a classification process arguably free of any evolutionary influences. The second period (1859–1949) includes a comparative synthesis on the classification of the Scarabaeoidea based on faunistic and taxonomic works. The third period (1950–2006) summarizes and analyzes classifications influenced by phylogenetic theories and is based on monographs, faunal studies, keys for regional fauna, papers on comparative morphology, and studies specifically devoted to the understanding of evolutionary relationships and processes in the Scarabaeoidea. A large problem concerning the classification and phylogeny still remains because most studies do not consider all the diversity of the Scarabaeoidea in a single analysis.

We present a preliminary overview of our molecular phylogenetics research on the superfamily Scarabaeoidea. The molecular data consists of 28S ribosomal DNA sequences (mainly D2 and D3 expansion regions) for over 600 taxa and 18S ribosomal DNA sequences (mainly E17 to E35 expansion regions) for over 150 representative taxa within the lineages sampled. Based on our preliminary molecular phylogenetic results, Scarabaeoidea includes three major groups: 1) Geotrupidae, Passalidae, and Pleocomidae; 2) Lucanidae, Diphyllostomatidae, Trogidae, and Glaresidae; and 3) Hybosoridae, Ochodaeidae, Glaphyridae, and Scarabaeidae. The broad evolutionary patterns within the Scarabaeoidea are discussed with respect to phylogeny and evolution.

Dung beetles employ numerous behavioral strategies to sequester dung away from other insects, and these have been broadly grouped into two categories: species that dig tunnels beneath the dung (tunnelers) and species that roll dung on the surface of the soil (rollers). Many species also are armed with rigid exoskeletal outgrowths called horns. Horns function as weapons, and horn sizes can be extreme. One widespread pattern within dung beetles is that tunneling species often have horns, whereas rolling species almost always do not, suggesting that residing (and fighting) inside tunnels at the dung deposition site may be an important ecological prerequisite for the evolution of horns in dung beetles. Here, we test explicitly for an historical association between tunneling behavior and the evolution of horns using a recent phylogeny for the scarabaeine dung beetles. We show that all eight of the independent gains of horns included in our analyses occurred on branches of the phylogeny reconstructed as tunneling, and that one of the three evolutionary losses of horns occurred on a branch that had lost tunneling behavior. We interpret this as evidence for a biologically meaningful association between tunneling behavior and the evolution of enlarged or exaggerated weapons such as horns, supporting the ideas of Eberhard and others that beetle horns may be most “beneficial” when used within the confines of restricted spaces such as burrows or tunnels.

Scarabaeoidea is one of the biogeographically best known groups of organisms for Nuclear Central America, especially Guatemala. They have been used to determine areas of endemism for cloud forests of the region and to analyze relationships among these endemic areas. A major north-south division of these areas is described. Lowland scenarios are also given. This information was used for justifying the establishment of biological reserves in the area and is a tool available for prioritization of reserve establishment that could be adapted to other parts of the world as well.

Invertebrate focal taxa that can act as information surrogates for broader patterns of biodiversity are of increasing interest to conservation practitioners. Scarabaeine dung beetles have been widely proposed as an ideal group for biodiversity inventory and monitoring, they satisfy all of the criteria of an ideal focal taxon, and they have already been used in ecological research and biodiversity survey and conservation work in many regions of the world. Here I review the characteristics that make the Scarabaeinae suitable for this purpose and suggest future directions for the broader use of this group as a focal taxon.

The use of scarab beetles (Coleoptera: Scarabaeidae) by primarily pre- and non-industrial peoples throughout the world is reviewed. These uses consist of (1) religion and folklore, (2) folk medicine, (3) food, and (4) regalia and body ornamentation. The use of scarabs in religion or cosmology, once widespread in ancient Egypt, exists only rarely today in other cultures. Scarabs have a minor role in folk medicine today although they may have been more important in the past. The predominant utilization of these beetles today, and probably in the past as well, is as food with emphasis on the larval stage. Lastly, particularly large or brightly colored scarabs (or their parts) are used (mostly in the New World) to adorn the body or as regalia.

The beetle family Scarabaeidae has a high diversity of species, and some of these have become important pests. Endemic scarab pests are known from all habitable continents but represent no more than a small percentage (probably 1–2%) of the total number of species. Some species have become international pests through human transport to new habitats. Scarab pests cause damage through larval feeding on plant roots or adult feeding on the aerial parts of plants. The pests are difficult to control due to the cryptic position of the larvae in the soil and the usually nocturnal activity of the adults. Chemical control is now focussed on specific chemicals with less residual activity. Biological control, especially with pathogens, has proven highly effective against some species, but control agents are often specific to a single species. Attractants ranging from sex pheromones to food lures have been isolated for scarabaeid species. Integration of control methods (IPM) has provided effective control of some species but there is a need for continued research to refine control measures and develop new options for management of this important group of pests.

The fossil record of scarab beetles (Coleoptera: Scarabaeoidea) is reviewed and its relevance for the reconstruction of the evolutionary history of the taxon is explored. After a discussion of the different kinds of preservation of scarab fossils, including preservation of color, the richest scarab deposits are identified. From the fossil record, the minimum age of Scarabaeoidea is determined as 152 myr. To develop an idea about the appearance of the first scarab, the ground-pattern of Scarabaeoidea is reconstructed for the first time on the basis of published phylogenetic analyses. Extinct scarabaeoid family-group taxa are described and discussed. Cretocomini and Cretoglaphyrini are upgraded to subfamily rank for reasons of consistency. Most of their diagnostic character states are controverted or not polarized. The minimum age of extant scarabaeoid family-group taxa is deduced from the fossil record. Ancient feeding habits, particularly the development of coprophagy, are discussed. The youngest extinct species described are from the Pleistocene, whereas extant species have been recorded since the Pliocene.

For the first time, all family-group names in the superfamily Scarabaeoidea (Coleoptera) are evaluated using the International Code of Zoological Nomenclature to determine their availability and validity. A total of 383 family-group names were found to be available, and all are reviewed to scrutinize the correct spelling, author, date, nomenclatural availability and validity, and current classification status. Numerous corrections are given to various errors that are commonly perpetuated in the literature. A reversal of precedence is used to preserve the prevailing usage of the following family-group names: Eupariini Schmidt, 1910 (over Ataeniini Harold, 1868); Pachydemini Burmeister, 1855 (over Elaphocerini Blanchard, 1851); Heterosternina Bates, 1888 (over Macropnina Horn, 1866); and Anomalina Streubel, 1839 (over Euchlorina Hope, 1839).