R. (2010). From 'cryptic species' to integrative taxonomy: an iterative process involving DNA sequences, morphology, and behaviour leads to the resurrection of Sepsis pyrrhosoma (Sepsidae: Diptera). -Zoologica Scripta, 39, 51-61. The increased availability of DNA sequences has led to a surge of 'cryptic species' in the literature. These units are usually proposed based on finding genetically distinct lineages within species that were initially defined based on morphological characters. However, few authors attempt to confirm whether these 'cryptic' units are species and even fewer authors are explicit about which species concept is applied. Here, we use an example from Sepsidae (Diptera) to demonstrate how cryptic species can be validated by an iterative process involving several data sources and an evaluation of the data under different species concepts. A phylogeographic analysis based on 50 specimens for five species of the flavimana group revealed deep mitochondrial splits within Sepsis flavimana which was suggestive of a cryptic species. We resolve the initial conflict between DNA sequences and morphology by adding new morphological data as well as behavioural evidence and tests for reproductive isolation. One cryptic species is confirmed and Sepsis pyrrhosoma, a former synonym of S. flavimana, is here shown to be a valid species under most species concepts. We can thus document that the same data can lead to similar conclusions under conflicting concepts once different kinds of data are integrated.

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Abstract. The males of almost all sepsid species have strongly modified forelegs that are used to clamp the female's wingbase during mounting. Here, we describe a new species in the genus Perochaeta whose males have unmodified forelegs. We use DNA sequence data for ten genes to reconstruct the position of Perochaeta on the phylogenetic tree for Sepsidae, and reveal that the lack of foreleg armature in Perochaeta dikowi sp.n. is secondary. Through the study of the mating behaviour of the new species, we demonstrate that the loss of armature is correlated with a new mounting technique during which the males of P. dikowi do not use the foreleg to clamp the female's wingbase. Instead, the male approaches the female from behind and bends his abdomen forwards in order to establish genital contact. Our study shows how data from morphology, phylogenetics, and behavioural biology can complement each other to yield a deeper understanding of how changes in morphology and behaviour are correlated.

Most of arthropod biodiversity is unknown to science. Consequently, it has been unclear whether insect communities around the world are dominated by the same or different taxa. This question can be answered through standardized sampling of biodiversity followed by estimation of species diversity and community composition with DNA barcodes. Here this approach is applied to flying insects sampled by 39 Malaise traps placed in five biogeographic regions, eight countries and numerous habitats (>225,000 specimens belonging to >25,000 species in 458 families). We find that 20 insect families (10 belonging to Diptera) account for >50% of local species diversity regardless of clade age, continent, climatic region and habitat type. Consistent differences in family-level dominance explain two-thirds of variation in community composition despite massive levels of species turnover, with most species (>97%) in the top 20 families encountered at a single site only. Alarmingly, the same families that dominate insect diversity are ‘dark taxa’ in that they suffer from extreme taxonomic neglect, with little signs of increasing activities in recent years. Taxonomic neglect tends to increase with diversity and decrease with body size. Identifying and tackling the diversity of ‘dark taxa’ with scalable techniques emerge as urgent priorities in biodiversity science.

Background The world’s fast disappearing mangrove forests have low plant diversity and are often assumed to also have a species-poor insect fauna. We here compare the tropical arthropod fauna across a freshwater swamp and six different forest types (rain-, swamp, dry-coastal, urban, freshwater swamp, mangroves) based on 140,000 barcoded specimens belonging to ca. 8500 species. Results We find that the globally imperiled habitat “mangroves” is an overlooked hotspot for insect diversity. Our study reveals a species-rich mangrove insect fauna (>3000 species in Singapore alone) that is distinct (>50% of species are mangrove-specific) and has high species turnover across Southeast and East Asia. For most habitats, plant diversity is a good predictor of insect diversity, but mangroves are an exception and compensate for a comparatively low number of phytophagous and fungivorous insect species by supporting an unusually rich community of predators whose larvae feed in the productive mudflats. For the remaining tropical habitats, the insect communities have diversity patterns that are largely congruent across guilds. Conclusions The discovery of such a sizeable and distinct insect fauna in a globally threatened habitat underlines how little is known about global insect biodiversity. We here show how such knowledge gaps can be closed quickly with new cost-effective NGS barcoding techniques.

Male abdomen appendages are a novel trait found within Sepsidae (Diptera). Here we demonstrate that they are likely to have evolved once, were lost three times, and then secondarily gained in one lineage. The developmental basis of these appendages was investigated by counting the number of histoblast cells in each abdominal segment in four species: two that represented the initial instance of appendage evolution, one that has secondarily gained appendages, and one species that did not have appendages.Males of all species with appendages have elevated cell counts for the fourth segment, which gives rise to the appendages. In Perochaeta dikowi, which reacquired the trait, the females also have elevated cell count on the fourth segment despite the fact that females do not develop appendages. The species without appendages has similar cell counts in all segments regardless of sex.These results suggest that the basis for appendage development is shared in males across all species, but the sexual dimorphism is regulated differently in P. dikowi. K E Y W O R D S :Appendage, developmental constraint, innovation, parallel evolution, Sepsidae.

Most of arthropod biodiversity is unknown to science. For this reason, it has been unclear whether insect communities around the world are dominated by the same or different taxa. This question can be answered through standardized sampling of biodiversity followed by estimation of species diversity and community composition with DNA sequences. This approach is here applied to flying insects sampled by 39 Malaise traps placed in five biogeographic regions, eight countries, and numerous habitats (>220,000 specimens belonging to >25,000 species in 463 families). Unexpectedly, we find that 20 insect families account for >50% of local species diversity regardless of continent, climatic region, and habitat type. These consistent differences in family-level dominance explain two-thirds of variation in community composition despite massive levels of species turnover, with most species (>97%) in the top 20 families encountered at a single site only. Alarmingly, the same families that dominate global insect diversity also suffer from extreme taxonomic neglect with little signs of increasing activities in recent years. Tackling the biodiversity of these "dark taxa" thereby emerges as an urgent priority because the arthropod groups comprising most of the global flying insect diversity are particularly poorly known.

Due to their interesting biology, conspicuous sexual dimorphism and the ability to conduct experiments on species that breed under laboratory condition, sepsid flies (Diptera : Sepsidae) are becoming increasingly important model organisms in evolutionary biology. Accurate species boundaries and well supported phylogenetic hypotheses are thus of interest to many biologists. Here we resolve the conflict surrounding the taxonomic status of the European Sepsis nigripes Meigen, 1826, which is shown to be a valid species using morphological and molecular data applied to multiple species concepts. The species is also placed onto a phylogenetic tree for the genus Sepsis that includes most European and North American species. In addition, we assess the genetic variability between two populations of the Holarctic Sepsis luteipes Melander & Spuler, 1917 from Europe and North America and find conflicting evidence between morphology and DNA sequences. Different species concepts here yield different inferences, and if two species were to be accepted based on molecular data, Sepsis helvetica Munari, 1985 from Europe would have to be resurrected from synonymy. We provide highresolution images for all species in order to aid in accurate identification. Both species are also added to Sepsidnet, the digital reference collection for Sepsidae (http://sepsidnet-rmbr.nus.edu.sg). Lastly, we discuss a field site in the Swiss Alps where 12 species of Sepsis occur sympatrically on the same pasture.