Molecular Phylogeny, Diversity and Zoogeography of Net-Winged Beetles (Coleoptera: Lycidae)

Structure and composition of a canopy-beetle community (Coleoptera) in a Neotropical lowland rainforest in southern Venezuela

Species richness, community structure and taxonomic composition are important characteristics of biodiversity. Beetle communities show distinct diversity patterns according to habitat attributes. Tropical rainforest canopies, which are well known for their richness in Coleoptera, represent such a conspicuous life zone. Here, I describe a canopy-inhabiting beetle community associated with 23 tree species in a Neotropical lowland rainforest. Adult beetles were sampled manually and in aerial traps using a large tower crane for a cumulative year. The sample revealed 6738 adult beetles, which were assigned to 862 (morpho-)species in 45 families. The most species-rich beetle families were Curculionidae (n = 246), Chrysomelidae (n = 121) and Cerambycidae (n = 89). The most abundant families were Curculionidae (n = 2746) and Chrysomelidae (n = 1409). Dominant beetle families were found in most assemblages. The beetle community consisted of 400 singletons (46.4%). A similar proportion was evident for assemblages of single tree species. I found that 74.5% of all beetle species were restricted in their occurrence on host trees to the phenological season and time of the day. This daily and seasonal migration causes patterns similar to mass effects and therefore accounts for the high proportion of singletons.

Phylogenetic analysis reveals a new net-winged beetle genus of Eurrhacini (Coleoptera, Lycidae) from the Pacific slopes of Central America and Ecuador

The first phylogenetic inference of Calopterini and Eurrhacini focused on Calocladon and related taxa was carried out. A data matrix composed of 46 species and 51 morphological characters was assembled and analyzed using parsimony and model-based approaches. Eurrhacini were recovered monophyletic. Furthermore, phylogenetic analyses highly supported the Calocladon clade including also Atlanticolycus, Cladocalon, and Gorhamium gen. nov. as its sister clade. Our trees consistently recovered monophyly of the new genus with two new species: Gorhamiumbidentatum sp. nov. (Panama, Baru Volcano) and G.unidentatum sp. nov. from the Pacific slopes of Ecuador. A revised key to the genera of Eurrhacini is given and illustrations of distinguishing characters are provided. Phylogenetic relationships of Eurrhacini and character evolution are discussed.

Taxonomic review of the genus Ponyalis Fairmaire, 1899 (Coleoptera, Lycidae), with descriptions of six new species from China

The lycid genus Ponyalis Fairmaire, 1899 is reviewed. Six new species are described from China, including P.longicornis sp. nov., P.truncata sp. nov., P.dabieshanensis sp. nov., P.hainanensis sp. nov., P.quadricollimima sp. nov., and P.zhejiangensis sp. nov. Nine previously known species, including P.alternata (Pic, 1927), P.fukiensis (Bocak, 1999), P.gracilis (Bocak, 1999), P.himalejica (Bourgeois, 1885), P.klapperichi (Bocak, 1999), P.laticornis Fairmaire, 1899, P.nigrohumeralis (Pic, 1939), P.quadricollis (Kiesenwetter, 1874), and P.variabilis Li, Bocak & Pang, 2015 are illustrated with images of the habitus and aedeagi to make the comparisons with the new species. In addition, a distribution map and an identification key to all 24 species of Ponyalis are provided.

A new genus of Eurrhacini from the Brazilian Atlantic Forest (Coleoptera: Lycidae: Lycinae) with an updated key to genera

Atlanticolycus gen. nov., is herein described as a new genus of Neotropical Lycidae in the Eurrhacini tribe. Five new species are described: Atlanticolycus camposgerais sp. nov., A. japi sp. nov., A. itatiaia sp. nov., A. ilhabela sp. nov., and A. morretes sp. nov., all distributed in Brazilian Atlantic Forest. Illustrations of diagnostic characters, a key for species identification and a key to genera of Eurrhacini with flabellate antennae are presented.

Untangling the evolution of soldier beetles (Coleoptera: Cantharidae) and the evaluation of the morphological phylogenetic signal in a soft-bodied elateroid lineage

This study addresses the long-standing uncertainty about the internal classification of soldier beetles (Elateroidea: Cantharidae). Four datasets were compiled and analysed: 66 genes for 14 terminals, 15 mtDNA genes for 79 terminals, one mtDNA and two rRNA genes for 217 terminals, and barcodes for 576 terminals. Based on congruent topologies, Chauliognathinae is proposed as a sister to the remaining Cantharidae, followed by the redefined Malthininae (including Tytthonyxini), the paraphyletic "dysmorphocerine" lineages (Dysmorphocerinae sensu stricto and Heteromastiginae subfam. nov.), and Silinae + Cantharinae as a terminal clade. The present phylogeny supersedes earlier morphology and short-fragment molecular hypotheses that have not converged on a consensus. Few morphological characters corroborate the DNA-based relationships (see the adults and larval keys). However, morphology-based hypotheses have relied on a few informative characters, and no evidence strongly rejects the preferred molecular topology. The interpretation of morphological characters and uncertain polarity resulting from the high phenotypic disparity of Elateroidea are discussed in detail. The dated phylogeny hypothesizes the earliest split within the Cantharidae in the Berriasian stage (Early Cretaceous, ~141 Myr) and the diversification of most extant subfamilies and tribes already in the Late Cretaceous. The most diverse subfamily, Cantharinae, represents a delayed radiation that started during the Eocene climatic optimum, 55.5 Myr. The late origin of Cantharinae questions the classification of Cretaceous Cantharidae as members of Cantharinae. Instead, the results suggest their deeper rooting after separating from dysmorphocerine lineages and before the node between Cantharinae and Silinae.

Eocene aposematic patterns persist in modern European Lycidae beetles despite the absence of co-mimics

Ancient aposematic signals might have evolved under different ecological circumstances. Using European Cenozoic amber and phylogenetic reconstruction, we evaluated the evolution of net-winged beetle aposematism. We describe Priabonian Hiekeolycus winkleri sp. nov. from Baltic amber, review known fossil species, and suggest earlier high diversity and morphological conservativeness of European Lycidae since the Eocene. We hypothesize the presence of red and black/red aposematic patterns in Eocene Europe. The analyses suggest the Oligocene to Miocene dispersal of additional species from East Asia and their advergence to autochthonous patterns. Recently dispersed lycids have retained similarities with their East Asian relatives. Net-winged beetles are rare in Europe after the Quaternary climatic oscillations, and we hypothesize a currently relaxed selection for shared aposematic signals. Neophobia, and eventually inborn rejection of brightly colored prey, putatively preserved ancient aposematism under changing conditions. Evidence from paleontology and phylogenetics can provide insight into the long-term persistence of old adaptations under changing conditions.

Unexpected High Species Diversity of Mesolycus Gorham (Coleoptera, Lycidae) from China, with a Preliminary Investigation on Its Phylogenetic Position Based on Multiple Genes

The lycid genus Mesolycus Gorham, 1883 is mainly distributed in East Palaearctic and Indochinese regions, but poorly studied in China; moreover, its phylogenetic placement remains controversial but has never been rigorously tested. In this study, Mesolycus was reviewed and its placement within Lycidae was tested based on a multilocus phylogeny (cox1, nad5, cox2 and Lrna) by both ML and BI analyses. The reconstructed phylogenies show that Mesolycus is a consistently recovered sister to Dilophotes Waterhouse, 1879, and they form a monophyletic clade which is well supported. This suggests that Mesolycus definitely belongs to Dilophotini rather than to Macrolycini of Lycinae. Besides, three species originally described or placed in Dilophotes are transferred to Mesolycus, including M. atricollis (Pic, 1926) comb. n., M. particularis (Pic, 1928) comb. n. and M. pacholatkoi (Bic, 2002) comb. n. Four new species are discovered in China, including M. shaanxiensis sp. n., M. dentatus sp. n., M. breviplatus sp. n. and M. varus sp. n. Two species, M. murzini Kazantsev, 2004 and M. rubromarginatus Kazantsev, 2013, are recorded from China for the first time. A key for the identification of all Mesolycus species is provided. China was revealed as the region with the highest species diversity of this genus.

Analysis of the Holarctic Dictyoptera aurora Complex (Coleoptera, Lycidae) Reveals Hidden Diversity and Geographic Structure in Müllerian Mimicry Ring

The elateroid family Lycidae is known for limited dispersal propensity and high species-level endemism. The red net-winged beetle, Dictyoptera aurora (Herbst, 1874), differs from all relatives by the range comprising almost the entire Holarctic region. Based on a five-marker phylogeny and 67 barcode entries (cox1-5' mtDNA) from the whole range, we recovered two genetically distinct species within traditionally defined D. aurora and resurrected the name D. coccinata (Say, 1835) as the oldest available synonym for Nearctic populations. Yet, no reliable morphological trait distinguishes these species except for minute differences in the male genitalia. D. coccinata is a monophylum resulting from a single Miocene dispersal event, ~15.8 million years ago, and genetic divergence implies long-term isolation by the Bering Strait. Far East Asian and west European populations are also genetically distinct, although to a lower extent. Two independent colonization events established the Fennoscandian populations after the last glacial maximum. Besides intrinsic factors, the high morphological similarity might result from stabilizing selection for shared aposematic signals. The rapidly accumulating barcode data provide valuable information on the evolutionary history and the origins of regional faunas.

Phylogenomic and mitogenomic data can accelerate inventorying of tropical beetles during the current biodiversity crisis

Conservation efforts must be evidence-based, so rapid and economically feasible methods should be used to quantify diversity and distribution patterns. We have attempted to overcome current impediments to the gathering of biodiversity data by using integrative phylogenomic and three mtDNA fragment analyses. As a model, we sequenced the Metriorrhynchini beetle fauna, sampled from ~700 localities in three continents. The species-rich dataset included ~6,500 terminals, ~1,850 putative species delimited at 5% uncorrected pairwise threshold, possibly ~1,000 of them unknown to science. Neither type of data could alone answer our questions on biodiversity and phylogeny. The phylogenomic backbone enabled the integrative delimitation of robustly defined natural genus-group units that will inform future research. Using constrained mtDNA analysis, we identified the spatial structure of species diversity, very high species-level endemism, and a biodiversity hotspot in New Guinea. We suggest that focused field research and subsequent laboratory and bioinformatic workflow steps would substantially accelerate the inventorying of any hyperdiverse tropical group with several thousand species. The outcome would be a scaffold for the incorporation of further data from environmental sequencing and ecological studies. The database of sequences could set a benchmark for the spatiotemporal evaluation of biodiversity, would support evidence-based conservation planning, and would provide a robust framework for systematic, biogeographic, and evolutionary studies.

Conspicuousness, phylogenetic structure, and origins of Müllerian mimicry in 4000 lycid beetles from all zoogeographic regions

Biologists have reported on the chemical defences and the phenetic similarity of net-winged beetles (Coleoptera: Lycidae) and their co-mimics. Nevertheless, our knowledge has remained fragmental, and the evolution of mimetic patterns has not been studied in the phylogenetic context. We illustrate the general appearance of ~ 600 lycid species and ~ 200 co-mimics and their distribution. Further, we assemble the phylogeny using the transcriptomic backbone and ~ 570 species. Using phylogenetic information, we closely scrutinise the relationships among aposematically coloured species, the worldwide diversity, and the distribution of aposematic patterns. The emitted visual signals differ in conspicuousness. The uniform coloured dorsum is ancestral and was followed by the evolution of bicoloured forms. The mottled patterns, i.e. fasciate, striate, punctate, and reticulate, originated later in the course of evolution. The highest number of sympatrically occurring patterns was recovered in New Guinea and the Andean mountain ecosystems (the areas of the highest abundance), and in continental South East Asia (an area of moderate abundance but high in phylogenetic diversity). Consequently, a large number of co-existing aposematic patterns in a single region and/or locality is the rule, in contrast with the theoretical prediction, and predators do not face a simple model-like choice but cope with complex mimetic communities. Lycids display an ancestral aposematic signal even though they sympatrically occur with differently coloured unprofitable relatives. We show that the highly conspicuous patterns evolve within communities predominantly formed by less conspicuous Müllerian mimics and, and often only a single species displays a novel pattern. Our work is a forerunner to the detailed research into the aposematic signalling of net-winged beetles.

Biodiversity Inventory and Distribution of Metriorrhynchina Net-Winged Beetles (Coleoptera: Lycidae), with the Identification of Generic Ranges

Simple Summary

We reviewed the classification of ~900 Metriorrhynchina net-winged beetles, and modified the alpha-taxonomy to reflect recently proposed phylogenetic hypotheses. There were >200 species transferred between subtribes and genera. The resulting checklist enabled us to identify New Guinea as the hotspot of Metriorrhynchina diversification. The centers of endemism include Sulawesi and New Guinea (in total 14 genera) in contrast with a single endemic genus in continental Australia. Most genera are diverse in New Guinea and the Wallacea, and only certain species crossed zoogeographic lines and colonized South East Asia. The study should boost the biodiversity research in the group and support biogeographic and evolutionary studies.

Abstract

We reviewed the species-level classification of Metriorrhynchina net-winged beetles to make the group accessible for further studies. Altogether, 876 valid species are listed in a checklist along with known synonyms, combinations, and distribution data. The compilation of geographic distribution showed that Metriorrhynchina is distributed mainly in the Australian region with very high diversity in the islands at the northern edge of the Australian craton, i.e., in the Moluccas and New Guinea (54 and 423 spp. respectively). The neighboring northern part of the Australian continent houses a majority of known Australian species (112 spp.) and the diversity of net-winged beetles gradually decreases to the south (43 spp.). The fauna of Sulawesi is highly endemic at the generic level (4 of 10 genera, 67 of 84 spp.). Less Metriorrhynchina occur in the Solomon Islands and Oceania (in total 22 spp.). The Oriental Metriorrhynchina fauna consists of a few genera and a limited number of species, and most of these are known from the Philippines (51 of 94 Oriental spp.). We identified a high species level turn-over between all neighboring landmasses. The genus-level endemism is high in Sulawesi (4 genera) and New Guinea (11 genera), but only a single genus is endemic to Australia. During the compilation of the checklist, we identified some homonyms, and we propose the following replacement names and a new synonym: Metriorrhynchus pseudobasalis, nom. nov. for M. basalis Lea, 1921 nec M. basalis Bourgeois, 1911; Metriorrhynchus pseudofunestus, nom. nov. for M. funestus Lea, 1921 nec M. funestus (Guérin-Méneville, 1838), Trichalus pseudoternatensis, nom. nov. for T. ternatensis Kleine, 1930 nec T. ternatensis Bourgeois, 1900, Procautires subparallelus, nom. nov. for P. parallelus (Pic, 1926) nec P. parallelus (Bourgeois, 1883), and Cautires pseudocorporaali, nom. nov. for C. corporaali (Pic, 1921: 12), (formerly Odontocerus and Cladophorus) nec C. corporaali (Pic, 1921) (formerly Bulenides, later Cautires). Diatrichalus biroi Kleine, 1943, syn. nov. is proposed as a junior subjective synonym of D. subarcuatithorax (Pic, 1926). Altogether, 161 new combinations are proposed, and 47 species earlier placed in Xylobanus Waterhouse, 1879 transferred from Cautirina to Metriorrhynchina incertae sedis. The study clarifies the taxonomy of Metriorrhynchini and should serve as a restarting point for further taxonomic, evolutionary, and biogeographic studies.

Sexually dimorphic characters and shared aposematic patterns mislead the morphology-based classification of the Lycini (Coleoptera: Lycidae)

The Lycini (Elateroidea: Lycidae) contains > 400 species placed in four typologically based genera and numerous subgenera. We assembled a mito-ribosomal dataset representing ~100 species from the whole range and recovered a phylogeny rejecting Lycus and Lycostomus as polyphyletic assemblages. The male-specific wide elytra and elytral thorns are identified in unrelated Neolycus and Lycus. The morphological similarity based on sexual dimorphism and aposematic patterns defined terminal clades and misled the genus-rank classification. We delimit Neolycus, Rhyncheros reinst. name (= Thoracocalon syn. nov. = Lyconotus syn. nov.), LipernesLycostomus, Haplolycus and Lycus. Demosis and six subgenera of Lycus are synonymized with Lycus. Celiasis Laporte, 1840 is kept in the classification as a nomen dubium until any specimen is available. The deep lineages are known from the Americas and Asia. Africa was colonized by Lycus and Haplolycus. Each specific aposematic pattern occurs in a limited range, and the similar body shape and coloration evolved in unrelated sympatrically occurring lineages. High intraspecific polymorphism is putatively a result of the adaptation of various populations to local mimetic assemblages. Therefore, the delimitation of many phenotypically diverse species should be investigated.

Interactions in multi-pattern Müllerian communities support origins of new patterns, false structures, imperfect resemblance and mimetic sexual dimorphism

Mimicry is a hot spot of evolutionary research, but de novo origins of aposematic patterns, the persistence of multiple patterns in Müllerian communities, and the persistence of imperfect mimics still need to be investigated. Local mimetic assemblages can contain up to a hundred of species, their structure can be a result of multiple dispersal events, and the gradual build-up of the communities. Here, we investigate the structure of lowland and mountain mimetic communities of net-winged beetles by sampling the Crocker Range in north-eastern Borneo and neighbouring regions. The local endemics evolved from the Bornean lowland fauna which is highly endemic at the species level. We inferred that metriorrhynchine net-winged beetles evolved in high elevations yellow/black and reticulate aposematic high-contrast signals from a widespread low-contrast brown/black pattern. As the mountain range is ~ 6 million years old, and these patterns do not occur elsewhere, we assume their in situ origins. We demonstrate that a signal with increased internal contrast can evolve de novo in a mimetic community and can persist despite its low frequency. Additionally, a similar aposematic signal evolves from different structures and its similarity is imperfect. The community with multiple patterns sets conditions for the evolution of aposematic sexual dimorphism as demonstrated by the yellow/black male and reticulate female pattern of Micronychus pardus. These insights elucidate the complex character of the evolution of mimetic signalling in the dynamically diversifying biota of high tropical mountains.

The Malacca Strait separates distinct faunas of poorly-flying Cautires net-winged beetles

We investigated the spatial and temporal patterns of Cautires diversification on the Malay Peninsula and Sumatra to understand if the narrow and frequently dry Malacca Strait separates different faunas. Moreover, we analyzed the origin of Cautires in Malayan and Sumatran mountains. We sampled 18 localities and present the mtDNA-based phylogeny of 76 species represented by 388 individuals. The phylogenetic tree was dated using mtDNA evolution rates and the ancestral ranges were estimated using the maximum likelihood approach. The phylogeny identified multiple lineages on the Malay Peninsula since the Upper Eocene (35 million years ago, mya) and a delayed evolution of diversity in Sumatra since the Upper Oligocene (26 mya). A limited number of colonization events across the Malacca Strait was identified up to the Pliocene and more intensive faunal exchange since the Pleistocene. The early colonization events were commonly followed by in situ diversification. As a result, the Malacca Strait now separates two faunas with a high species-level turnover. The montane fauna diversified in a limited space and seldom took part in colonization events across the Strait. Besides isolation by open sea or a savannah corridor, mimetic patterns could decrease the colonization capacity of Cautires. The Malay fauna is phylogenetically more diverse and has a higher value if conservation priorities should be defined.