Frank-Thorsten Krell

Parataxonomy vs. taxonomy in biodiversity studies - pitfalls and applicability of 'morphospecies' sorting

Parataxonomic sorting of samples to recognizable taxonomic units (RTUs, morphospecies, morphotypes or, as proposed here: parataxonomic units [PUs]) is generally considered to be a sufficiently reliable and conservative approach in ecological biodiversity studies or conservation biology. It is obviously time-saving because it avoids the burdens of taxonomy. However, evaluations of parataxonomic sorting by taxonomic resorting show many overestimations of species numbers. Hence, RTU sorting is not necessarily conservative. Sorting errors can be more than 100% (median in the present compilation: 22%). Even if the cumulative results for diverse groups like beetles have a very low overall error, the error rate in the single families is generally much higher. This pattern is likely to cause severe problems in multivariate analyses. The presumable error rate in sorting does not depend only on the group to be sorted, but also on the sorter and the sample. Therefore, the sorting error is not predictable. Since PUs are generally neither described nor assigned to existing names, the sorting results are difficult to check and it is mostly not revealed why the samples are sorted as they are. Since parataxonomy does not use existing biological knowledge, creates typological units and does not disclose its sorting criteria, inter-subjective testability and falsifiability of the sorting results are more difficult than of taxonomic identifications (or are even impossible). Parataxonomy does not fulfil the criteria of a scientific method, but is propedeutic and can be a heuristically valuable tool to find out patterns in taxonomically neglected groups. However, it is only the first step in sorting and identifying samples in biodiversity studies. PUs are useless for inventories and area selection in conservation evaluation, biogeographical and autecological studies; they provide only uncertain data for studies in species turnover and overlap, but they can be used quite reliably for global comparisons of gross species richness, non-comparative descriptions of species richness of single sites or for comparisons of sites without species overlap. If results of parataxonomic sorting show clear and biologically meaningful patterns, the sorting is likely to be reliable. Weak or no detectable patterns may easily be caused by erroneous sorting.

The fossil record of Mesozoic and Tertiary Scarabaeoidea (Coleoptera : Polyphaga)

Lack of characters, similarity of stem species of adelphotaxa and the necessity to know the extant world fauna of the studied group of fossils are the main difficulties in palaeontology of beetles. The paucity of characters of most of the fossils of supposed Scarabaeoidea prevents their inclusion in a reliable phylogenetic analysis. Only rarely can an autapomorphy of Scarabaeoidea be seen in a fossil classified as a member of this group. Therefore, the classification of Mesozoic and Tertiary fossils is often tentative. Based on a critical literature review of all recorded fossil Scarabaeoidea from the Mesozoic and Tertiary, the minimum age for families and/or subfamilies of this group is determined. An annotated catalogue of named fossils and ichnofossils of Scarabaeoidea and of their lagerstAtten is given. 238 fossil species and subspecies of this group have been described, of which 27 are doubtful, eight already identified as belonging to other taxa, and two subspecies synonymised with extant taxa. 189 species and 12 ichnospecies probably or reliably belong to the Scarabaeoidea. Nomenclatural acts: Hongscarabaeus, nom. nov. for Proscarabaeus Hong, 1982 (nec Schrank, 1781); Onthophagus urusheeri, nom. nov. for Onthophagus urus Heer, 1847 (nec Menetries, 1832); Aphodius anteactus, nom. nov. for Aphodius antiquus Heer, 1847 (nec Faldermann, 1835); Aphodius theobaldi, nom. nov. for Aphodius incertus Theobald, 1937 (nec Ballion, 1878); Anomala palaeobrunnea, nom. nov. for Anomala brunnea (Hong, 1985) (nec Klug, 1855); Eophyllocerus scrobiculatus Haupt, 1950 is designated as the type species of Eophyllocerus Haupt, 1950; Cangabola Lengerken, 1955 is a junior synonym of Coprinisphaera Sauer, 1955. ‘Mais en presence des Coleopteres, sauf tres rares exeptions, tout specialiste serieux ne peut que se recuser’. R. Jeannel (1942: 191) on fossil faunas.

Quinone Mixture as Attractant for Necrophagous Dung Beetles Specialized on Dead Millipedes

Abstract2-Methyl-1,4-benzoquinone (toluquinone) and 2-methoxy-3-methyl-1,4-benzoquinone are the most common components of defensive secretions of juliform millipedes (Diplopoda: Juliformia). A natural and a synthetic millipede-defensive secretion composed of these two substances attract dung beetles of a few Onthophagus species (Coleoptera: Scarabaeidae) that feed mainly on freshly dead millipedes. This olfactory mechanism and adaptation to the toxic effects of quinones enables them to be the first and exclusive users of this resource.

The terrestrial arthropods of Mauritius: a neglected conservation target

Entomology in Mauritius has historically been linked with the agricultural and medical fields but concern should now be directed towards the conservation of native forest insects given that they are key components of the local ecosystem. Despite its young age, small size and remoteness, the island has a well-developed native insect fauna with a high proportion of endemic species. A majority of the insect orders are represented on the island. We document the current state of knowledge for Mauritian arthropods, with particular focus on the Coleoptera. This is the most diverse order locally with 1,032 species. In addition, it is the best catalogued historically, providing a framework for future conservation studies to evaluate the current status of this group. We explore the current threats facing the native insect fauna and highlight the needs for concern on this vital component of local biodiversity. We recognize that the initial step for conserving the native insects will depend largely on the establishment of a local taxonomic knowledge base with international expert input.

Finding a Rare Resource: Bornean Scarabaeoidea (Coleoptera) Attracted by Defensive Secretions of Diplopoda

Abstract Scarab beetles of four species, Onthophagus penicillatus Harold, O. rudis Sharp, Phaeochridius derasus (Harold) and Phaeochroops gilleti (Benderitter) (Scarabaeoidea: Scarabaeidae and Hybosoridae) were attracted by quinonous defensive secretions of Harpagophoridae (Diplopoda) in Sabah, Borneo. Unlike the Afrotropics, where some specialists feed on fresh millipede carcasses, in Borneo only generalist necrophages use this resource. This may be caused by the low abundance of juliform Diplopoda in Borneo prohibiting specialization on this resource.

Timeless standards for species delimitation

Recently a new species of bombyliid fly, Marleyimyia xylocopae, was described by Marshall & Evenhuis (2015) based on two photographs taken during fieldwork in the Republic of South Africa. This species has no preserved holotype. The paper generated some buzz, especially among dipterists, because in most cases photographs taken in the field provide insufficient information for properly diagnosing and documenting species of Diptera.

Making the cryptic visible – resolving the species complex of Aphodius fimetarius (Linnaeus) and Aphodius pedellus (de Geer) (Coleoptera: Scarabaeidae) by three complementary methods

Species in cryptic complexes are, per definition, difficult to identify using morphological characters. One such complex was recently detected in the dung beetle Aphodius fimetarius (Linnaeus) sensu lato, an abundant dung beetle with a wide distribution. While the two component taxa, Aphodius fimetarius sensu stricto and Aphodius pedellus (De Geer) exhibit distinctly different karyotypes, the validity of subtle morphological characters proposed to distinguish between them has been debated. Given the variability and minor interspecific differences in external characters, the large‐scale distribution of respective taxa has remained unknown, as have potential differences in ecology and habits. In this study, we ask how A. fimetarius and A. pedellus can best be distinguished, whether the use of different types of characters (karyotypes, DNA sequences and morphological traits) results in consistent species identification, where these species occur and whether they exhibit ecological differences. In total, we inspected a material of 4401 individuals from across the globe, of which 183 were examined for both mtDNA sequences and morphology, 154 for both morphology and karyotype, and 9 (including the recently proposed neotype of Aphodius fimetarius) for all three types of characters. As a marker gene, we sequenced a 590 bp region of the cytochrome c oxidase I gene for 183 individuals. Overall, DNA sequences offered a clear‐cut distinction between taxa: sequences of A. fimetarius and A. pedellus differed by an average pairwise distance of 8.2%, whereas variation within species was only 0.9% for A. fimetarius and 0.5% for A. pedellus. Morphological and chromosomal characters offered species identifications consistent with that of molecular characters: karyotypes identified as A. pedellus consistently fell within one of the molecular clades, whereas karyotypes identified as A. fimetarius fell within the other clade. Likewise, the majority of individuals identified by morphological characters were assigned to the same species by sequence‐based characters. Both taxa thus defined were found to be Holarctic in distribution, with major sympatry within Central and Southern Europe and mixed patterns of sympatry within the US. Northern areas of Europe, Asia and North America are dominated by A. pedellus alone. Within A. pedellus, patterns of sequence diversity were indicative of a recent population expansion. In the western US, the phenology of a population of A. fimetarius was observed to significantly differ from that of a sympatric population of A. pedellus, thereby revealing an ecological difference between the two cryptic taxa. Overall, we conclude that all types of characters offered a consistent classification of the two species. Thus, the laborious karyotyping techniques used to originally establish the presence of two cryptic taxa can now be substituted by characters more easily applied to large ecological samples. Using this approach of integrative taxonomy, we were able to establish the global distribution and species‐specific ecology of these ecologically important cryptic taxa.

The Poverty of Citation Databases: Data Mining Is Crucial for Fair Metrical Evaluation of Research Performance

For a long time, the journal impact factor has been used to evaluate the scientific performance of authors. It is increasingly recognized, however, that judging an author’s scientific performance should take into account that author’s scientific output, and not the output of other authors publishing in the same journal—the citation rates of papers in one journal can vary enormously, and the journal impact factor fails to that consider that variance. The number of citations an author attracts is a reliable measure of the attention the author receives from the scientific community, or, in other words, of the scientific impact of an author. (Attention is a lame arbiter of scientific quality, but that is a problem that cannot be solved by any simple metrics.) In 2005, Jorge E. Hirsch proposed a simple, elegant measure of an author’s impact: the h index, which is the number of an author’s papers (h) with at least h citations. Other author-based indexes have been proposed, such as the g index, which, given a set of papers ranked in decreasing order of the number of citations received, is the largest number such that the top g articles received together at least g 2 citations (Egghe 2006). The g index better takes into account the citation scores of top articles.

The beetle fauna of hyaena latrines: coprocenoses consisting of necrophagous beetles (Coleoptera Trogidae Scarabaeidae)

The scarab beetle fauna (Coleoptera Scarabaeoidea) on Spotted Hyaena, Crocuta crocuta (Erxleben 1777), scats was investigated to identify the feeding guilds of scarabs on an unusual dung substrate. During 19 months inspecting hyaena latrines and surrounding roads, 69 specimens of 8 species of Scarabaeoidea (Trogidae and Scarabaeidae) were collected from 200 hyaena faeces samples and 17 samples of regurgitated hairs. With increasing amount of hairs in the samples, attraction to hyaena faeces increased (from dry, white faeces to soft, brownish faeces to regurgitated hairs). Most of the scarab species that we found feed generally on carrion and omnivore/carnivore dung. Three species have not previously been found on carrion but are likely to be (facultative) necrophages. Further records of beetles from hyaena faeces indicate that almost all species that are attracted by this bait are at least facultatively necrophagous. The dung part of their diet consists mainly of omnivore or carnivore faeces as is usual for necro-coprophagous species.

Cetoniinae Developing in a Living Stalk of Bromeliaceae (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini)

Abstract Larvae of Desicasta laevicostata (van de Poll 1886) (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini) were found developing in living stalk tissue of the bromeliad Vriesea sanguinolenta Cogn. and Marchal (Bromeliaceae) in Panama. This is the first record of Cetoniinae using living plant tissue as a larval substratum. The male of this species is described for the first time and its aedeagus is figured.