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The phylogenetic status of the family Nitidulidae and its sister group relationship remain controversial. Also, the status of the subfamily Meligethinae is not fully understood, and previous studies have been mainly based on morphology, molecular fragments, and biological habits, rather than the analysis of the complete mitochondrial genome. Up to now, there has been no complete mitochondrial genome report of Meligethinae. In this study, the complete mitochondrial genomes of Meligethinus tschungseni and Brassicogethes affinis (both from China) were provided, and they were compared with the existing complete mitochondrial genomes of Nitidulidae. The phylogenetic analysis among 20 species of Coleoptera was reconstructed via PhyloBayes analysis and Maximum likelihood (ML) analysis, respectively. The results showed that the full lengths of Meligethinus tschungseni and Brassicogethes affinis were 15,783 bp and 16,622 bp, and the AT contents were 77% and 76.7%, respectively. Each complete mitochondrial genome contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and a control region (A + T-rich region). All the PCGs begin with the standard start codon ATN (ATA, ATT, ATG, ATC). All the PCGs terminate with a complete terminal codon, TAA or TAG, except cox1, cox2, nad4, and nad5, which terminate with a single T. Furthermore, all the tRNAs have a typical clover-leaf secondary structure except trnS1, whose DHU arm is missing in both species. The two newly sequenced species have different numbers and lengths of tandem repeat regions in their control regions. Based on the genetic distance and Ka/Ks analysis, nad6 showed a higher variability and faster evolutionary rate. Based on the available complete mitochondrial genomes, the results showed that the four subfamilies (Nitidulinae, Meligethinae, Carpophilinae, Epuraeinae) of Nitidulidae formed a monophyletic group and further supported the sister group relationship of Nitidulidae + Kateretidae. In addition, the taxonomic status of Meligethinae and the sister group relationship between Meligethinae and Nitidulinae (the latter as currently circumscribed) were also preliminarily explored.

Tire wear microplastic particles (TWMPs) are emerging microplastic pollutants that have gained increasing attention lately. However, the health effect of inhaled airborne TWMPs has never been explored before and may already be included in particulate matter morbidity and mortality. Here, we endeavored to address the preliminary study of TWMP inhalation-induced pulmonary toxic effects and its epigenetic mechanisms in C57BL/6 mice. As a result, restricted ventilatory dysfunction and fibrotic pathological changes were observed in TWMP-treaded mice. Further research found that attenuation of miR-1a-3p plays an important role in TWMP-induced lung injury. Results from in vitro study confirmed that cytoskeleton regulatory gene twinfilin-1 was one of the target genes of miR-1a-3p, and involved in cytoskeleton rearrangement caused by TWMP exposure. Mechanistically, miR-1a-3p inhibited the F-actin formation by targeting cytoskeletal regulatory proteins twinfilin-1, leading to TWMP-induced pulmonary fibrotic injury. While we are in the very early stages of explaining the role of epigenetics in TWMP-induced lung injury, the potential for the use of epigenetic marks as biomarkers is high and discoveries made in this field will likely bring us closer to better understanding this crucial mechanism.

Abstract Background Meligethes are pollen-beetles associated with flowers of Rosaceae as larvae. This genus currently consists of 63 known species in two subgenera, Meligethes and Odonthogethes, predominantly occurring in the eastern Palaearctic. We analyzed 74 morphological and ecological characters (169 states) of all species, as well as of 11 outgroup species from 7 Meligethinae genera (including Brassicogethes), to investigate their phylogeny. We also conducted a parallel molecular analysis on 9 Meligethes, 9 Odonthogethes, 3 Brassicogethes and 2 Meligethinus species based on DNA sequence data from mitochondrial (COI, 16S) and nuclear (CAD) genes. Results Morphological phylogenetic reconstructions supported the monophyly of the whole genus and clades corresponding to purported subgenera Meligethes s.str. and Odonthogethes. Main species-groups were mostly confirmed, however some unresolved polytomies remained. Molecular data placed members of Brassicogethes (including 42 mostly W Palearctic species associated with Brassicaceae) as sister to Odonthogethes, with this clade being sister to Meligethes s.str. This phylogenetic scenario suggests that monophyletic Meligethes s.str., Odonthogethes and Brassicogethes should be regarded alternatively as three subgenera of a monophyletic Meligethes, or three genera in a monophyletic genus-complex, with mutually monophyletic Brassicogethes and Odonthogethes. Molecular analyses estimated the origin of this lineage at ca. 14–15 Mya from a common stem including Meligethinus. Conclusions We hypothesize that the ancestor of Meligethes specialized on Rosaceae in the Middle Miocene (likely in Langhian Age) and subsequently radiated during Late Miocene and Plio-Pleistocene maintaining a trophic niche on this plant family. This radiation was primarily due to geographic isolation in E Asiatic mountain systems. Combined evidence from morphology, ancestral state parsimony reconstruction of host-plant associations and molecular evidence suggested that Rosoideae (Rosa spp.) represented the ancestral hosts of Meligethes s.str., followed by an independent shift of ancestral Odonthogethes (ca. 9–15 Mya) on Rubus (Rosoideae) and members of Rosaceae Spiraeoideae. Other ancestral Odonthogethes probably shifted again on the unrelated plant family Brassicaceae (maybe 8–14 Mya in S China), allowing a rapid westward radiation of the Brassicogethes clade.

Meligethes (Odonthogethes) chinensis is a highly specialized species of Nitidulidae in China that takes pollen as its main food source, and its main host plant is Rubus idaeus L. (Rosaceae). In this study, the structural morphology of the alimentary canal and Malpighian tubules of adult M. (O.) chinensis was observed under light, fluorescence, and scanning electron microscopy. The alimentary canal of adult M. (O.) chinensis is divided into foregut, midgut, and hindgut. The foregut is the shortest and consists of the pharynx, esophagus, proventriculus, and cardiac valve. The midgut is a straight, distended, cylindrical, thin-walled tube. Numerous blunt-fingered gastric ceca are distributed irregularly throughout the midgut. The hindgut is subdivided into the ileum, colon, and rectum. The ileum is coiled. The colon gradually enlarges posteriorly. The rectum is thickly muscled and followed by a membranous structure. The openings of proximal Malpighian tubules are evenly inserted into the junction of the midgut and hindgut, and distal Malpighian tubules are evenly attached to the colon to form a cryptonephridial system. In this study, we also compare the structure and infer the function of the alimentary canal and Malpighian tubules among beetles, as well as discuss the evolutionary and taxonomical implications.

In this paper we present the description of male genitalia and additional information on taxonomy of three recently described and poorly known Chinese endemic members of the genus Meligethes Stephens, 1830, Meligethes (Odonthogethes) brassicogethoides Audisio, Sabatelli & Jelínek, 2015, M. (O.) inexpectatus Liu, Huang, Cline, Sabatelli & Audisio, 2017, and M. (O.) tricuspidatus Liu, Huang, Cline & Audisio, 2018.

Recent molecular and morphological data derived from members of the pollen-beetle subfamily Meligethinae suggest the need to separate the genus Sagittogethes Audisio and Cline, 2009, including species mostly distributed in Western Palaearctic areas, into two distinct (although related) genera, Sagittogethes and Teucriogethes gen. n. This new genus, comprising the Western European Meligethes obscurus Erichson, 1845 as its type species, includes less than ten species distributed between the Iberian Peninsula and North Africa westward, and China and Japan eastward. All inclusive species utilize members of the genus Teucrium L. (Lamiacaeae: Ajugoideae) as larval host-plants. Morphological and bionomical information, and molecular data clearly demonstrate the necessity for updating the taxonomic position of the two clades. Based on molecular evidence, the new genus represents the sister-group of Thymogethes Audisio and Cline, 2009, while the sister-group relationships of the remaining Sagittogethes taxa with other Lamiaceae-associated genera of Meligethinae remain uncertain. Within the new genus, the relictual and rare Western Mediterranean species T. minutus (C.N.F. Brisout de Barneville, 1863) seems to occupy an isolated position.

Two new species of the genus Lamiogethes Audisio & Cline, 2009 are described from China (Sichuan): L. forcipenis sp. n., and L. convexistrigosus sp. n., based on a series of recently collected specimens. The new species are both likely morphologically related to L. potanini (Kirejtshuk, 1979) from Sichuan and to L. conjungens (Grouvelle, 1910) from Yunnan. These new species clearly differ from their related taxa by details of the body shape and color, and the distinct shape of the male and female genitalia. Both new species are likely associated as larvae with a member of the genus Phlomoides Moench (Lamiaceae).

The subfamily Lamiinae is the most taxonomically diverse subfamily of Cerambycidae, but relationships between tribes of Lamiinae are still unresolved. In order to study the characteristics of the mitogenomes of Lamiinae and the tribal-level phylogenetic relationships, we sequenced the mitogenomes of two species representing two tribes, Agapanthia amurensis (Agapanthiini) and Moechotypa diphysis (Ceroplesini), with a total length of 15,512 bp and 15,493 bp, respectively. The gene arrangements of these two new mitogenomes were consistent with the inferred ancestral insect mitogenomes. Each species contained 37 typical mitochondrial genes and a control region (A + T-rich region), including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs). All PCGs initiated with the standard start codon ATN, and terminated with the complete stop codons of TAA and TAG, or incomplete stop codon T. All tRNAs could be folded into a clover-leaf secondary structure except for trnS1, in which the dihydrouridine (DHU) arm was reduced. Moreover, we studied the phylogenetic relationships between some tribes of Lamiinae based in mitochondrial PCGs in nucleotides; our results show that the relationships were as follows: (Onciderini + ((Apomecynini + Acanthocinini) + ((Ceroplesini + Agapanthiini) + ((Mesosini + Pteropliini) + ((Dorcaschematini + (Saperdini 1 + (Phytoeciini + Saperdini 2))) + (Batocerini + Lamiini)))))).

Meligethes (Odonthogethes) chinensis is a common Chinese phytophagous species in the family Nitidulidae. Its main larval host plant is Rubus idaeus L. (Rosaceae), and adults feed on pollen and other floral parts. In this study, we used scanning electron microscopy (SEM) to observe and study the fine morphology of sensilla on the antennae and mouthparts of M. chinensis. The results show that there are six types and twelve subtypes of sensilla on male antennae; seven types and fourteen subtypes on female antennae; seven types and seventeen subtypes on male mouthparts; seven types and sixteen subtypes on female mouthparts. Sensilla coeloconica (SCo) are found on the female antennae of M. chinensis only, and they are also reported on the antennae of Nitidulidae for the first time. SCo2 on the labrum present sexual dimorphism, and one subtype of sensilla basiconica (SB6) is presented on the tip of maxillary and labial palps of the male only, while other types of sensilla are very similar on the mouthparts of male and female. Finally, by comparing similar sensilla in other insects, we also attempted to discuss the functions of all sensilla on the antennae and mouthparts of M. chinensis.

Meligethes (Odontogethes) inexpectatus sp. n. is described from China, Sichuan Province. The new species is based on a female specimen previously incorrectly referred to as Meligethes scrobescens Chen, Lin, Huang & Yang, 2015, which was recently described from a series of male specimens collected in the same area. Both species belong to the taxonomically difficult species-group related to M. chinensis Kirejtshuk, 1979, including a dozen closely related species distributed throughout Nepal and SW and Central China. The true female of Meligethes scrobescens is also described, based on recently collected material from China (Hubei and Chongqing), including a series of male and female specimens. Diagnostic characters distinguishing the new species from all other known members of the M. chinensis species-group and species-complex are discussed, and their overall range distribution are depicted. Additional data on geographic distribution and larval ecology of some of the closely related species are also reported.

Recent molecular and morphological data derived from members of the pollen-beetle subfamily Meligethinae suggest the need to separate the genus Sagittogethes Audisio & Cline, 2009, including species mostly distributed in Western Palaearctic areas, into two distinct (although related) genera, Sagittogethes and Teucriogethes gen. n. This new genus, comprising the Western European Meligethes obscurus Erichson, 1845 as its type species, includes less than ten species distributed between the Iberian Peninsula and North Africa westward, and China and Japan eastward. All inclusive species utilize members of the genus Teucrium L. (Lamiacaeae: Ajugoideae) as larval host-plants. Morphological and bionomical information, and molecular data clearly demonstrate the necessity for updating the taxonomic position of the two clades. Based on molecular evidence, the new genus represents the sister-group of Thymogethes Audisio & Cline, 2009, while the sister-group relationships of the remaining Sagittogethes taxa with other Lamiaceae-associated genera of Meligethinae remain uncertain. Within the new genus, the relictual and rare Western Mediterranean species T. minutus (C.N.F. Brisout de Barneville, 1863) seems to occupy an isolated position. [ABSTRACT FROM AUTHOR]