Sister Group Research Articles

Genetic architecture underlying the parallel evolution of leaf ecomorphs in Viburnum

Abstract In a neotropical lineage of the plant clade Viburnum (Adoxaceae) several leaf ecomorphs evolved independently and repeatedly as the group radiated through cloud forests of North and South America. Here, we focus on one pair of co-occurring sister species within this radiation with strongly contrasting leaf morphotypes and document the presence of phenotypically diverse and genetically admixed hybrid individuals in multiple hybrid swarms. Hybrid phenotypes are generally intermediate in form, but sometimes show parental or entirely novel and transgressive combinations of leaf traits, suggesting that parental leaf ecomorphs can be functionally and genetically dissociated. We used admixture mapping within hybrid swarms to investigate the genetic architecture of key traits comprising these leaf ecomorphs and uncovered loci proximal to known genes implicated in leaf development, including some that may alter multiple leaf traits simultaneously, potentially facilitating the emergence of leaf syndromes. We conclude that the shared genetic architecture underlying some traits, such as leaf size and marginal teeth, could promote the repeated evolution of these traits in concert, while low levels of genetic linkage between other leaf traits supports the hypothesis that selection promoted the repeated assembly of particular combinations of leaf traits as Viburnum radiated throughout the neotropics.

The discovery of an overseen pygmy backswimmer in Europe (Heteroptera, Nepomorpha, Pleidae).

The Pleidae, or pygmy backswimmers, is a family of aquatic bugs (Hemiptera, Heteroptera, Nepomorpha) containing four genera. Here, we describe Plea cryptica sp. nov. and redescribe its sister species, Plea minutissima Leach, 1817. Whereas the morphological distinction of these closely related species is only possible for males, molecular data clearly separate them. As part of our taxonomic study, we provide comprehensive molecular data including more than 200 DNA barcodes from all over Europe, complete nuclear ribosomal DNA, full mitochondrial genome data, and 3D scans for both species. Furthermore, the same molecular markers are also presented for Neoplea striola (Fieber, 1844). We used Maximum Likelihood (ML) analyses to reconstruct the phylogeny of the Pleidae and Notonectoidea based on available mitogenomic data. Our study represents a successful implementation of the proposed concept of taxonomics, using data from high-throughput sequencing technologies for integrative taxonomic studies, and allowing high confidence for both biodiversity and ecological research.

Morphological and molecular data demonstrate the existence of Betula fruticosa and B. middendorffii and the absence of B. ovalifolia in northeastern China

Abstract Shrub birches are important components of massive wetlands in Northeast China, although much of these habitats have been lost over the past two decades. However, the taxonomy of shrub birches has been ambiguous owing to their morphological variation. In this study, we incorporated morphological and molecular data to address the taxonomic challenges associated with shrub birches. We characterized the morphological variation in the leaves, seeds, and bracts of 11 shrub birch populations in Northeast China and a population of Betula ovalifolia in northern Japan. We genotyped birch individuals from Northeast China at 15 microsatellite loci as well as a subset of individuals, using restriction site-associated DNA sequencing (RAD-seq). The populations in Northeast China consisted of B. fruticosa and B. middendorffii. These two species and B. ovalifolia differ in the width of their seed wings and the angle between the side lobes of their bracts, despite substantial intraspecific variation. Our genetic data revealed two distinct clusters, corresponding to B. fruticosa and B. middendorffii. Ploidy level assessment via RAD-seq revealed that B. fruticosa is diploid and B. middendorffii is tetraploid. Phylogenetic analysis revealed that B. fruticosa formed a sister clade to diploid B. humilis, and B. middendorffii formed a clade with diploid B. nana. Our results indicate the existence of B. fruticosa and B. middendorffii and the probable absence of B. ovalifolia in the northern Daxing’an Range, as all the tetraploid individuals sampled there represented B. middendorffii. In addition, our results suggest that B. humilis and B. nana may have served as diploid parents of the tetraploid species B. ovalifolia and B. middendorffii, respectively.

Elymus multiramosus (Poaceae), a new species from the north-western Qinghai-Tibetan Plateau, China

A new species from China, Elymus multiramosus Y.C. Zhang, sp. nov. is described and illustrated herein, based on morphological characters and molecular phylogenetic analysis. The taxonomic descriptions of E. multiramosus and the comparison with related species are presented. The taxonomic distinctiveness of this new species was inferred by Maximum Likelihood (ML) analysis and Bayesian phylogenetic analysis, based on the complete chloroplast genome sequence. It is assigned to the Elymus section and bears similarity to Elymus nutans Griseb. However, it can be easily distinguished from other species by its compound spike, in contrast to the simple spike inflorescence typical of those species. The compound spike is characterised by rhachillas that are extended at the base of the main axis, giving rise to 3–6 mini-spike-like branches. Notably, these branches significantly increase in length from the top towards the bottom of the compound spike. In the molecular phylogeny, Elymus multiramosus from Qinghai, north-western China, is phylogenetically positioned as a distinct lineage. The lineage comprising Elymus sinosubmuticus from Sichuan, east of the Tibetan Plateau and Elymus nutans from the Himalayas forms a sister group to Elymus multiramosus, suggesting that these three species share a common ancestor that is distinct from the lineage leading to Elymus atratus from Gansu, north of the Tibetan Plateau.

A New Species of the Cyrtodactylus pulchellus Group (Squamata: Gekkonidae) from Surat Thani Province, Thailand Underscores This Group’s Remarkable Diversity on the Thai-Malay Peninsula

An integrative taxonomic study recognized a new species of the Cyrtodactylus pulchellus group from Kanchanadit District, Surat Thani Province, Southern Thailand. Phylogenetic analyses of the mitochondrial ND2 gene revealed a new species, Cyrtodactylus kanchanaditsp. nov., that is closely related to C. lekaguli. The new species differs from its sister lineage by bearing mean genetic divergence of 4.53% and significant differences in both mensural and morphometric characters (p < 0.05). Cyrtodactylus kanchanaditsp. nov. can be differentiated from the remaining members of the C. pulchellus species group because of its genetic divergence of ≥7.99% and a combination of differences in body size: 11–15 supralabial and 10–12 infralabial scales, 29–35 paravertebral tubercles, 18–23 longitudinal rows of dorsal tubercles, 32–37 rows of ventral scales, 20–23 subdigital lamellae on the fourth toe, 32–37 femoroprecloacal pores in adult males, and four or five dark body bands; weak tuberculation on body; absence of tubercles in the ventral body fold, absence of precloacal pores in females, and absence of scattered pattern of white tubercles on dorsum; presence of precloacal groove depression; and maculated white caudal bands. Cyrtodactylus kanchanaditsp. nov. is currently known from its type locality.

Catalogue of fungi in China 4: Didymiaceae and Physaraceae (Myxomycetes)

ABSTRACT Myxomycetes play crucial ecological roles, yet their species diversity, distribution, and taxonomic relationships remain poorly understood. In this study, we examined 104 specimens from 19 provinces in China. Through morphological analysis, we identified a group of species with reduced lime formation, a feature typically associated with the Physaraceae, but with key morphological similarities to the Diderma. A comprehensive phylogenetic analysis was conducted using three genes (nSSU, EF-1α, and COI), resulting in a dataset of 452 sequences from 116 species. Notably, we identified a distinct clade within Didymiaceae containing species with fewer lime knots, a trait traditionally linked to Physaraceae. This clade, designated as the new genus Neodiderma, was phylogenetically positioned as a sister group to Diderma, potentially representing a transitional group between Didymiaceae and Physaraceae, supported by both morphological and molecular evidence. Eleven new species — N. macrosporum, N. pseudobisporum, N. verrucocapillitium, N. rigidocapillitium, N. rufum, Physarum guangxiense, P. subviride, P. nigritum, P. biyangense, P. neoovoideum, and P. jilinense — were identified from China, and their phylogenetic positions were analysed. Additionally, N. spumarioides (formerly Diderma spumarioides) was recombined. The new and recombined species were formally described and illustrated, and a key to the sections and species of Neodiderma and Physarum was provided.

A newborn F-box gene blocks gene flow by selectively degrading phosphoglucomutase in species hybrids

The establishment of reproductive barriers such as postzygotic hybrid incompatibility (HI) remains the key to speciation. Gene duplication followed by differential functionalization has long been proposed as a major model underlying HI, but little supporting evidence exists. Here, we demonstrate that a newborn F-box gene, Cni-neib-1, of the nematode Caenorhabditis nigoni specifically inactivates an essential phosphoglucomutase encoded by Cbr-shls-1 in its sister species Caenorhabditis briggsae and their hybrids. Zygotic expression of Cni-neib-1 specifically depletes Cbr-SHLS-1, but not Cni-SHLS-1, in approximately 40 min starting from gastrulation, causing embryonic death. Cni-neib-1 is one of thirty-three paralogues emerging from a recent surge in F-box gene duplication events within C. nigoni, all of which are evolving under positive selection. Cni-neib-1 undergoes turnover even among C. nigoni populations. Differential expansion of F-box genes between the two species could reflect their distinctive innate immune responses. Collectively, we demonstrate how recent duplication of genes involved in protein degradation can cause incidental destruction of targets in hybrids that leads to HI, providing an invaluable insight into mechanisms of speciation.

A new species of Fissidentalium (Scaphopoda: Dentaliidae) in association with an actinostolid anemone from the abyssal Labrador Sea

The benthic biodiversity of the abyssal Labrador Sea was investigated using Agassiz trawl and in situ imagery. A megafaunal scaphopod associated with an epizoic anemone was recovered from soft sediments. Morphological and molecular investigations revealed the scaphopod to be an undescribed species in the dentaliid genus Fissidentalium P. Fischer, 1885. The new scaphopod species is characterised by a large size for the genus, is moderately curved, with numerous narrow, longitudinal ribs (60 ribs at 11 mm diameter ventral aperture), a dentaliid radula, and is described herein as Fissidentalium aurae sp. nov. The new species shows a close genetic relationship to congeners of Fissidentalium and separates from the sister genera Dentalium Linnaeus, 1758 and Antalis H. Adams & A. Adams, 1854. Genetic COI barcoding of the epizoic anemone suggests the species is a member of the family Actinostolidae Carlgren, 1932. The discovered association of a burrowing scaphopod with an epifaunal anemone at abyssal depth is a new record for the region and is indicative of how little is known about symbioses in the deep sea.

Seeking the first phylogenetic method–Edvard A. Vainio (1853–1929) and his troubled endeavour towards a natural lichen classification in the late nineteenth century Finland

Edvard August Vainio was a world-renowned Finnish lichenologist. In Finland, however, he was a controversial person due to his strong pro-Finnish political views. Equally disputed was his opinion that systematics should be based on evolutionary theory and phylogenetic thinking. Vainio was familiar with the ideas of the early German phylogeneticists—especially those of Carl Wilhelm von Nägeli – and, applying them, aimed to create an exact method for building a natural classification of lichens already at the end of the nineteenth century. In this respect, Vainio was a true pioneer, as no actual phylogenetic method had yet been developed. In the general spirit of the time, Vainio focused on finding the ancestors of species and other taxa by comparing primitive and derived features of homologous characters. However, Vainio already understood the concept of sister groups in 1880, the identification of which is the basis of all modern phylogenetic research. Nevertheless, the distinctive method developed by Vainio was not so much focused on the construction of a phylogenetic tree, but on revealing the origin of species through the differentiation and fixation of their polymorphic variation. Indeed, Vainio’s species concept is surprisingly similar to the phylogenetic species concepts presented a hundred years later. Although in many ways progressive, Vainio’s views did not influence the development of phylogenetics more widely, but his discussions are nevertheless a valuable source to understanding the early development of phylogenetic theory.

A new species of Hypancistrus Isbrücker & Nijssen 1991 (Loricariidae, Siluriformes) from the rapids of the middle Rio Tocantins.

The Hypancistrus genus is recognized in the Río Orinoco basin and Rio Xingu in the Guiana and Brazilian Shields, respectively. Some of its species are important in ornamental fishing. Despite this significance, many other undescribed species are still awaiting to be named. Here we describe a new species of Hypancistrus found on bedrock in the Rio Tocantins, representing an extension of the distribution of the genus. Also, a multigene phylogeny is presented to evaluate the taxonomic position of this species concerning congeners. The new species differs from all congeners by (1) hypertrophied odontodes on cheeks reaching beyond the cleithrum, (2) a supraoccipital crest conspicuously elevated, (3) a supraorbital crest slightly convex, (4) oblique bars on the anterior part of the body, (5) a dark E-shaped mark on the snout, (6) three oblique dark bars on the anterior part of the body and horizontal vermicular bars from the pectoral girdle to the posterior insertion of the dorsal fin, (7) a thin light gray bar on the posterior of the head extending across the branchial opening, (8) a tan background color, (9) a developed suspensorium with a diminished appendix in the metapterygoid, and (10) a dentary plate robust significantly fused with the angulo-articular bone. The molecular phylogenetic results show the new species forming a group with Hypancistrus zebra (Brazilian Shield-Rio Xingu) as a clade, a sister group of a monophyletic group consisting of all congeners from the Río Orinoco.

Evolution of g-type lysozymes in metazoa: insights into immunity and digestive adaptations

Exploring the evolutionary dynamics of lysozymes is critical for advancing our knowledge of adaptations in immune and digestive systems. Here, we characterize the distribution of a unique class of lysozymes known as g-type, which hydrolyze key components of bacterial cell walls. Notably, ctenophores, and choanoflagellates (the sister group of Metazoa), lack g-type lysozymes. We reveal a mosaic distribution of these genes, particularly within lophotrochozoans/spiralians, suggesting the horizontal gene transfer events from predatory myxobacteria played a role in their acquisition, enabling specialized dietary and defensive adaptations. We further identify two major groups of g-type lysozymes based on their widespread distribution in gastropods. Despite their sequence diversity, these lysozymes maintain conserved structural integrity that is crucial for enzymatic activity, underscoring independent evolutionary pathways where g-type lysozymes have developed functionalities typically associated with different lysozyme types in other species. Specifically, using Aplysia californica as a reference species, we identified three distinct g-type lysozyme genes: two are expressed in organs linked to both feeding and defense, and the third exhibits broader distribution, likely associated with immune functions. These findings advance our understanding of the evolutionary dynamics shaping the recruitment and mosaic functional diversification of these enzymes across metazoans, offering new insights into ecological physiology and physiological evolution as emerging fields.

Termites and subsocial roaches inherited many bacterial-borne carbohydrate-active enzymes (CAZymes) from their common ancestor

Termites digest wood using Carbohydrate-Active Enzymes (CAZymes) produced by gut bacteria with whom they have cospeciated at geological timescales. Whether CAZymes were encoded in the genomes of their ancestor’s gut bacteria and transmitted to modern termites or acquired more recently from bacteria not associated with termites is unclear. We used gut metagenomes from 195 termites and one Cryptocercus, the sister group of termites, to investigate the evolution of termite gut bacterial CAZymes. We found 420 termite-specific clusters in 81 bacterial CAZyme gene trees, including 404 clusters showing strong cophylogenetic patterns with termites. Of the 420 clusters, 131 included at least one bacterial CAZyme sequence associated with Cryptocercus or Mastotermes, the sister group of all other termites. Our results suggest many bacterial CAZymes have been encoded in the genomes of termite gut bacteria since termite origin, indicating termites rely upon many bacterial CAZymes endemic to their guts to digest wood.

A history of multiple Denisovan introgression events in modern humans.

The identification of a new hominin group in the Altai mountains called Denisovans was one of the most exciting discoveries in human evolution in the last decade. Unlike Neanderthal remains, the Denisovan fossil record consists of only a finger bone, jawbone, teeth and skull fragments. Leveraging the surviving Denisovan segments in modern human genomes has uncovered evidence of at least three introgression events from distinct Denisovan populations into modern humans in the past. Each of them presents different levels of relatedness to the sequenced Altai Denisovan, indicating a complex relationship between these sister lineages. Here we review the evidence suggesting that several Denisovan populations, who likely had an extensive geographical range, were adapted to distinct environments and introgressed into modern humans multiple times. We further discuss how archaic variants have been affected by demographic history, negative and positive selection and close by proposing possible new lines of future research.

Seven mitochondrial genomes of tribe Hylurgini (Coleoptera: Curculionidae: Scolytinae) in Eurasia and their phylogenetic analysis.

The Hylurgini tribe (Coleoptera: Curculionidae: Scolytinae) comprises commercially significant bark beetles, including invasive species within the genera Dendroctonus and Hylurgus. These invasive species coexist with native Tomicus species of Hylurgini and cooperatively infest host trees in China. However, we lack sufficient mitochondrial genome data of Hylurgini to conduct phylogenetic studies, clarify the phylogenetic relationships of the above species, and improve the understanding of niche divergence and common hazards. Here, we sequenced and analyzed the mitochondrial genomes of seven Hylurgini species, including Dendroctonus valens, Hylurgus ligniperda, Hylurgus micklitzi, Tomicus piniperda, Tomicus brevipilosus, Tomicus minor and Tomicus yunnanensis. All sequenced mitochondrial genomes ranged from 15,339 bp to 17,545 bp in length, and their AT contents ranged from 73.24% to 78.81%. The structure of the seven mitochondrial genomes was consistent with that of ancestral insects. Based on 13 protein-coding genes from the reported mitochondrial genomes of 29 species of bark beetles, we constructed phylogenetic trees using maximum likelihood and Bayesian inference methods. The topology of the two phylogenetic trees was almost consistent. The findings elucidated the taxonomy classification of Hylurgini and the evolutionary connections of its sister taxa within the Scolytinae. This study offers insights for examining the evolutionary connections between invasive and native bark beetles, as well as the molecular identification and detection of newly invading species.

Phylogenetics and reticulation among koelerioid clades, part I: Contraction of Trisetum, expansion of Acrospelion, Graphephorum, and Tzveleviochloa; Graciliotrisetum gen. nov. and resurrection of Aegialina (Poaceae, Pooideae, Poeae, Aveninae)

AbstractKoelerioid grasses (subtribe Aveninae, tribe Poeae; Pooideae) resolve into two major clades, here called Koelerioid Clades A and B. Phylogenetic relationships among koelerioid grasses are investigated using plastid DNA sequences of rpl32‐trnL, rps16‐trnK, rps16 intron, and ITS regions, focusing on Trisetum, Acrospelion, and some annual species (Rostraria p.p. and Trisetaria p.p.) closely related to Trisetum flavescens in Koelerioid Clade A. Phylogenetic analyses of several selected data sets performed for 80 taxa and using maximum likelihood and Bayesian methods, revealed mostly congruent topologies in the nuclear and plastid trees, but also reticulation affecting several lineages. Trisetum is restricted to one species, T. flavescens, which is a sister to the clade formed by Trisetum gracile and Trisetaria aurea. The latter two species are classified here in the genus Graciliotrisetum gen. nov. The sister clade includes three species of Rostraria and Trisetaria lapalmae, all of which are classified here in a resurrected genus, Aegialina, which includes four species. Acrospelion is enlarged to include 13 species after the addition of other species formerly classified in Trisetum sect. Trisetum and T. sect. Acrospelion. We also transfer Trisetum ambiguum, Trisetum longiglume, and Koeleria mendocinensis to Graphephorum; and Helictotrichon delavayi to Tzveleviochloa, expanding these genera to eight and six species, respectively. We evaluate cases of reticulate evolution between Koelerioid Clades A and B and within Koelerioid Clade A, which probably gave rise to Graphephorum, Rostraria cristata, and Rostraria obtusiflora. Finally, we comment on polyploidy and biogeographic patterns in koelerioid grasses. We propose the following 26 new combinations: Acrospelion alpestre, Acrospelion altaicum, Acrospelion argenteum, Acrospelion bertolonii, Acrospelion buschianum, Acrospelion buschianum subsp. transcaucasicum, Acrospelion fuscum, Acrospelion laconicum, Acrospelion macrotrichum, Acrospelion rigidum, Acrospelion rigidum subsp. teberdense, Acrospelion tamonanteae, Acrospelion velutinum, Aegialina lapalmae, Aegialina pubescens, Aegialina pumila, Aegialina pumila subsp. fuscescens, Aegialina salzmannii, Aegialina salzmannii subsp. cossoniana, Graciliotrisetum aureum, Graciliotrisetum gracile, Graphephorum ambiguum, Graphephorum longiglume, Graphephorum mendocinense, Graphephorum orthochaetum, and Tzveleviochloa delavayi. Lectotypes are designated for the names Aegialitis tenuis, Aira melicoides, Avena aspera var. parviflora, Avena delavayi, Koeleria grisebachii var. mendocinensis, Koeleria pubescens subsp. cossoniana, Koeleria pumila, Koeleria salzmannii, Phalaris pubescens, Trisetum aureum, Trisetum cernuum, Trisetum fuscescens, Trisetum longiglume, and Trisetum wolfii; and we designate one neotype for Alopecurus litoreus.

Insight into the Phylogenetic Relationships of Phasmatodea and Selection Pressure Analysis of Phraortes liaoningensis Chen & He, 1991 (Phasmatodea: Lonchodidae) Using Mitogenomes

Stick and leaf insects are a group among the Insecta that are famous for their extraordinary mimicry ability. Since the establishment of the Phasmatodea, their internal classification has been constantly revised. Mitochondrial genes as molecular markers have been widely used for species classification, but the phylogenetic relationships within the Phasmatodea remain to be thoroughly discussed. In the present study, five mitogenomes of Phasmatodea ranging from 15,746 bp to 16,747 bp in length were sequenced. Bayesian inference (BI) and maximum likelihood (ML) analyses were carried out based on a 13 PCGs data matrix (nt123) and a combined matrix of 13 PCGs and two rRNA genes (nt123_rRNA). The present study supports the conclusion that Phylliidae was the basal group of Neophasmatodea and confirms the monophyly of Lonchodinae and Necrosciinae, but it shows that Lonchodidae was polyphyletic. A sister group of Bacillidae and Pseudophasmatidae was also recovered. The phylogenetic tree based on the nt_123 dataset showed higher node support values. The construction of a divergent time tree in this study supported the conclusion that extant Phasmatodea originated in the Jurassic (170 Mya) and most lineages diverged after the Cretaceous–Paleogene extinction event. To explore whether the mitochondrial genes of Phraortes liaoningensis collected from high latitudes where low temperatures occur for eight months of the year are under selection pressure, this study used the branch-site model and the branch model to analyze the selection pressure on the 13 mitochondria protein-coding genes (PCGs). We found that both ND2 and ND4L of Ph. liaoningensis exhibited positive selection sites using the branch-site model. This study shows that a low-temperature environment causes mitochondrial genes to be selected to meet the energy requirements for survival.

Genome Assembly of the Nematode Rhabditoides Inermis From a Complex Microbial Community.

Free-living nematodes such as Caenorhabditis elegans and Pristionchus pacificus are powerful model systems for linking specific traits to their underlying genetic basis. To trace the evolutionary history of specific traits or genes, a robust phylogenomic framework is indispensable. In the context of the nematode family Diplogastridae to which P. pacificus belongs, the identity of a sister group has long been debated. In this work, we generated a pseudochromosome level genome assembly of the nematode Rhabditoides inermis, which has previously been proposed as the sister taxon. The genome was assembled from a complex microbial community that is stably associated with R. inermis isolates and that consists of multiple bacteria and a fungus, which we identified as a strain of Vanrija albida. The R. inermis genome spans 173.5Mb that are largely assembled into five pseudochromosomes. This chromosomal configuration likely arose from two recent fusions of different Nigon elements. Phylogenomic analysis did not support a sister group relationship between R. inermis and diplogastrids, but rather supports a sister group relationship between the monophyletic Diplogastridae and a group of genera of Rhabditidae including C. elegans and R. inermis. Thus, our work addresses for the first time the long lasting question about the sister group to diplogastrids at the phylogenomic level and provides with the genomes of R. inermis and the associated fungus V. albida valuable resources for future genomic comparisons.

Phylogenetic analysis of the complete mitochondrial genome of the orange-winged sulphur butterfly Dercas nina Mell 1913 (Insecta: Lepidoptera: Pieridae: Coliadinae)

Dercas nina Mell 1913 (Pieridae) is a little-studied butterfly species endemic to China that flies primarily in the forest canopy. Genome skimming by Illumina sequencing allowed assembly of 146,702 reads for complete 1471.3-fold mean coverage of the circular 15,264 bp mitogenome from D. nina consisting of 82.1% AT nucleotides. A gene order typical of butterflies was recovered consisting of 13 protein-coding genes, 22 tRNAs, two rRNAs, and a predicted control region. The Dercas nina COX1 open reading frame begins with atypical start codon CGA. Six protein-coding genes (COX1, COX2, ND2, ND3, ND4, ND5) with single-nucleotide (T) stop codons, and two protein-coding genes (ATP6, ATP8) with two-nucleotide (TA) stop codons encoded in the DNA were inferred to be completed by adenine nucleotides from the Poly-A tail of the mRNA. Bayesian’s phylogenetic reconstruction places the D. nina and D. lycorias mitogenomes as sister clades. Dercas mitogenomes were sister to those from genus Colias in the monophyletic subfamily Coliadinae. The mitogenome phylogeny is consistent with previous molecular phylogenetic hypotheses based on other markers, but differs somewhat from a morphology-based hypothesis that suggested that Dercas was more closely related to genus Gonepteryx. This may falsify the hypothesis or may instead reflect mitochondrial-nuclear phylogenetic discordance.

A new species of Acossus Dyar (Lepidoptera: Cossidae) establishes diurnal flight in New World carpenter-moths

Synthetic pheromones formulated for Acossus centerensis Lintner, 1877 led to the discovery of a new taxonomically cryptic species, Acossus boreocryptus Schmidt & Jaeger sp. nov. Adult males were active only during the daytime, exceptional among cossid moths, and the first documented case of diurnality in New World Cossidae. Males were attracted to lures baited with (E,E) 3,5-tetradecadienyl acetate (EE-TDDA). The larval host plant of A. boreocryptus is trembling aspen, Populus tremuloides Michx., but the immature stages remain undescribed. Acossus boreocryptus is the smallest species in the genus, distinguished from its sister species A. centerensis by adult morphology, mtDNA barcode, male diurnal activity, and seasonal phenology.

Field-evolved resistance to neonicotinoids in the mosquito, Anopheles gambiae, is associated with mutations of nicotinic acetylcholine receptor subunits combined with cytochrome P450-mediated detoxification

New insecticides prequalified for malaria control interventions include modulators of nicotinic acetylcholine receptors that act selectively on different subunits leading to variable sensitivity among arthropods. This study aimed to investigate the molecular mechanisms underlying contrasting susceptibility to neonicotinoids observed in wild populations of two mosquito sibling species. Bioassays and a synergist test with piperonyl butoxide revealed that the sister taxa, Anopheles gambiae and An. coluzzii, from Yaounde, Cameroon, both have the potential to develop resistance to acetamiprid through cytochrome P450-mediated detoxification. However, contrary to An. coluzzii, An. gambiae populations are evolving cross-resistance to several active ingredients facilitated by mutations of nicotinic acetylcholine receptors (nAChRs). We sequenced coding regions on the β1 and α6 nAChR subunits where variants associated with resistance to neonicotinoids or to spinosyns have been found in agricultural pests and detected no mutation in An. coluzzii. By contrast, six nucleotide substitutions including an amino acid change in one of the loops that modulate ligand binding and affect sensitivity were present in the resistant species, An. gambiae. Allele frequency distributions were consistent with the spread of beneficial mutations that likely reduce the affinity of An. gambiae nAChRs for synthetic modulators. Our findings provide critical information for the application and resistance management of nAChR modulators in malaria prevention.