Recent origin and diversification accompanied by repeated host shifts of thallus-mining flies (Diptera: Agromyzidae) on liverworts and hornworts.

Despite the vast diversity of phytophagous insects that feed on vascular plants (tracheophytes), insects that feed on bryophytes remain understudied. Agromyzidae, one of the most species-rich phytophagous clades in Diptera, consists mainly of leaf-mining species that feed on tracheophytes. However, a recent discovery of thallus-mining species on liverworts and hornworts within the Liriomyza group of Phytomyzinae provides an opportunity to study host shifts between tracheophytes and bryophytes. This study aimed to explore the origin and diversification of thallus-miners and estimate the pattern and timing of host shifts. Phylogenetic analysis of Phytomyzinae has revealed that the thallus-mining agromyzids formed a separate clade, which was sister to a fern pinnule-miner. The diversification of bryophyte-associated agromyzids since the Oligocene involved multiple host shifts across various bryophyte taxa. The diversification of the thallus-mining Phytoliriomyza may have occurred at the same time as the leaf-mining agromyzid flies on herbaceous plants, indicating a dynamic history of interactions between bryophytes and herbivores in angiosperms-dominated ecosystems.

Oldest leaf mine trace fossil from East Asia provides insight into ancient nutritional flow in a plant-herbivore interaction.

The Late Triassic saw a flourish of plant-arthropod interactions. By the Late Triassic, insects had developed all distinct strategies of herbivory, notably including some of the earliest occurrences of leaf-mining. Herein we describe exceptionally well-preserved leaf-mine trace fossils on a Cladophlebis Brongniart fern pinnule from the Momonoki Formation, Mine Group, Japan (Middle Carnian), representing the oldest unequivocal leaf-mines from East Asia. The mines all display a distinctive frass trail-a continuous meandering line, which later becomes a broad band containing spheroidal particles-demonstrating larval development. Although the shapes of the frass trails are generally comparable to those of Lepidoptera or Coleoptera, they cannot be unequivocally assigned to a specific extant leaf-mining taxon. Furthermore, elemental analyses by X-ray fluorescence (XRF) reveals that the frass trail comprises phosphate coprolites. The quantitative variations in P, S, and Si between coprolites and leaf veins may reflect physiological processes (e.g., consumption, absorption, and excretion) mediated by plant chemicals. Our findings reinforce the idea that leaf-mining had become a pervasive feeding strategy of herbivorous insects by the Late Triassic.

Notes on the taxonomic status and distribution of some Cylindrotomidae (Diptera, Tipuloidea), with emphasis on Japanese species.

A morphological and molecular study of 17 Cylindrotomidae species revealed that the two subspecies of Cylindrotomadistinctissima, the Nearctic C.americana Osten Sacken, 1865, stat. reval. and the Palearctic C.distinctissima (Meigen, 1818), represent separated lineages and consequently are raised to species level. Cylindrotomajaponica Alexander, 1919, syn. nov. and C.distinctissimaalpestris Peus, 1952, syn. nov. are now known to be junior synonyms of C.distinctissima. Triogmakuwanailimbinervis Alexander, 1953, syn. nov. and T.nimbipennis Alexander, 1941, syn. nov. are now placed into synonymy under Triogmakuwanai (Alexander, 1913). The Japanese Cylindrotomidae are all redescribed and all available literature and distribution data are summarised. Supplementary descriptions and illustrations for male and female terminalia of Cylindrotomanigriventris Loew, 1849, Diogmadmitrii Paramonov, 2005, Liogmanodicornis (Osten Sacken, 1865), Phalacrocerareplicata (Linnaeus, 1758), P.tipulina Osten Sacken, 1865, and Triogmatrisulcata (Schummel, 1829) are provided. The following new distribution records are outlined; Diogmacaudata Takahashi, 1960 from Arkhangelsk Oblast, Russia; D.glabrata (Meigen, 1818) from Belarus, Latvia, and Altai Republic, Amur Oblast, Novgorod Oblast, Magadan Oblast, Samara Oblast, and Kuril Islands (Shikotan I and Paramushir I) in Russia; Liogmaserraticornis Alexander, 1919 from Khabarovsk Krai, Russia; Phalacrocerareplicata from Khabarovsk Krai, Russia; and the presence of Cylindrotomanigriventris in Altai Republic, Russia is confirmed.

Diversity underfoot of agromyzids (Agromyzidae, Diptera) mining thalli of liverworts and hornworts.

Agromyzidae is a dipteran family that has diversified as internal plant feeders. Although most agromyzid species feed on herbaceous angiosperms, only a limited number of species has been recorded as miners of bryophytes. Extensive searches and rearing of bryophytivores in the Japanese Archipelago were made, resulting in that thallus-mining agromyzids are overwhelmingly widespread and diverse on thalloid liverworts and hornworts. By examining the morphology of adult flies, it was revealed that the agromyzid fauna comprise 39 species, of which 37 species are newly described. All the species are assigned to the genus Phytoliriomyza Hendel based on some shared morphological character states as follows: costa reaching M1; orbital setulae minute and erect (rarely proclinate); male epandrium with combs of fused tubercle-like setae and/or hypertrophied arms bearing tubercle-like setae; male distiphallus comprising a pair of stout, extended tubules; female cercus with two stout, apical, trichoid sensilla. Of the 39 agromyzid species in Japan, 36 species are associated with liverworts: 5 spp. on Marchantia (Marchantiaceae), 2 spp. on Dumortiera (Dumortieraceae), 3 spp. on Plagiochasma, 1 sp. on Asterella, 6 spp. on Reboulia (Aytoniaceae), 1 sp. on Wiesnerella (Wiesnerellaceae), 15 spp. on Conocephalum (Conocephalaceae), and 3 spp. on Riccia (Ricciaceae). Three species are associated with hornworts: 1 sp. on Folioceros (Anthocerotaceae), 1 sp. on Megaceros (Dendrocerotaceae), and 1 sp. on Notothylas,Phaeoceros (Notothyladaceae), and Anthoceros (Anthocerotaceae). The results suggest that 37 of the 39 species are host-specific at least to plant genus level, and that the inter-specific differences in male genitalia and color patterns of scutum, antenna, and maxillary palpus have contributed to reproductive isolation on the bryophytes that the flies share.

First Annotated Genome of a Mandibulate Moth, Neomicropteryx cornuta, Generated Using PacBio HiFi Sequencing.

We provide a new, annotated genome assembly of Neomicropteryx cornuta, a species of the so-called mandibulate archaic moths (Lepidoptera: Micropterigidae). These moths belong to a lineage that is thought to have split from all other Lepidoptera more than 300 Ma and are consequently vital to understanding the early evolution of superorder Amphiesmenoptera, which contains the order Lepidoptera (butterflies and moths) and its sister order Trichoptera (caddisflies). Using PacBio HiFi sequencing reads, we assembled a highly contiguous genome with a contig N50 of nearly 17 Mb. The assembled genome length of 541,115,538 bp is about half the length of the largest published Amphiesmenoptera genome (Limnephilus lunatus, Trichoptera) and double the length of the smallest (Papilio polytes, Lepidoptera). We find high recovery of universal single copy orthologs with 98.1% of BUSCO genes present and provide a genome annotation of 15,643 genes aided by resolved isoforms from PacBio IsoSeq data. This high-quality genome assembly provides an important resource for studying ecological and evolutionary transitions in the early evolution of Amphiesmenoptera.

A novel leaf-rolling chironomid, Eukiefferiella endobryonia sp. nov. (Diptera, Chironomidae, Orthocladiinae), highlights the diversity of underwater chironomid tube structures.

The non-biting midges, Chironomidae (Diptera), are dominant components of most freshwater ecosystems. Many chironomids construct tubes or cases as larvae out of various materials bound together with silk. The structures of tubes show a wide range of variation, and some are morphologically comparable to those of caddisflies. Herein a new species is described, Eukiefferiella endobryonia sp. nov., which exhibits a very unusual behavior in which it constructs tubes from aquatic mosses. This species' fourth-instar larvae construct their cases exclusively from the leaves of Fontinalis mosses (Hypnales: Fontinalaceae) and exhibit a stereotyped behavior in which they remain attached to the apical shoot of the moss stem. The larvae then pupate within the case. The case of E. endobryonia sp. nov. represents one of only a few examples of chironomid tubes made exclusively out of plants. Based on the species delimitation analyses using the partial COI sequences, together with some morphological and behavioral characteristics, this species is hypothesized to be a member of devonica group, and especially may have a close affinity to E. dittmari (Lehman). A provisional typology for the diversity of chironomid tube structures is provided, with a summary of different tube structures, which can be used for future research.

Bryophyte-Feeders in a Basal Brachyceran Lineage (Diptera: Rhagionidae: Spaniinae): Adult Oviposition Behavior and Changes in the Larval Mouthpart Morphology Accompanied with the Diet Shifts.

Dipteran larval morphology exhibits overwhelming variety, affected by their diverse feeding habits and habitat use. In particular, larval mouthpart morphology is associated with feeding behavior, providing key taxonomic traits. Despite most larval Brachycera being carnivorous, a basal brachyceran family, Rhagionidae, contains bryophyte-feeding taxa with multiple feeding habits. To elucidate the life history, biology, and morphological evolution of the bryophyte-feeding rhagionids, the larval feeding behavior and morphology, and the adult oviposition behavior of four species belonging to three genera of Spaniinae (Spania Meigen, Litoleptis Chillcott and Ptiolina Zetterstedt) are described. Moreover, changes of the larval morphology associated with the evolution of bryophyte-feeding are traced by molecular phylogenetic analyses. Spania and Litoleptis (thallus-miners of thallose liverworts) share a toothed form of apical mandibular sclerite with an orifice on its dorsal surface, which contrasts to those of the other members of Rhagionidae possessing a blade-like mandibular hook with an adoral groove; whereas, Ptiolina (stem borer of mosses) exhibits a weak groove on the adoral surface of mandible and highly sclerotized maxilla with toothed projections. Based on the larval feeding behavior of the thallus-miners, it is inferred that the toothed mandibles with the dorsal orifice facilitate scraping plant tissue and then imbibing it with a great deal of the sap. A phylogeny indicated that the bryophyte-feeding genera formed a clade with Spaniopsis and was sister to Symphoromyia, which presumably are detritivores. This study indicates that the loss or reduction of adoral mandibular groove and mandibular brush is coincident with the evolution of bryophyte-feeding, and it is subsequently followed by the occurrence of dorsal mandibular orifice and the loss of creeping welts accompanying the evolution of thallus-mining.

Bryophyte-feeding of Litoleptis (Diptera: Rhagionidae) with descriptions of new species from Japan.

Here we report the larval phytophagous habit of Litoleptis for the first time, and describe six new species of Litoleptis in Japan; L. japonica n. sp., L. kiiensis n. sp., L. niyodoensis n. sp., L. himukaensis n. sp., L. izuensis n. sp., and L. asterellaphile n. sp. All the species described here are thallus-miners of liverworts belonging to Aytoniaceae and Conocephalaceae (Marchantiopsida: Marchantiophyta). Each fly species mined thalli of only one of the following genera: Conocephalum, Reboulia, and Asterella. The descriptions of the Japanese Litoleptis species here expand the concept of this genus. The female genital morphology of Litoleptis strengthened the current placement of Litoleptis as a member of Spaniinae.

Allopatric distribution and diversification without niche shift in a bryophyte-feeding basal moth lineage (Lepidoptera: Micropterigidae).

The Lepidoptera represent one of the most successful radiations of plant-feeding insects, which predominantly took place within angiosperms beginning in the Cretaceous period. Angiosperm colonization is thought to underlie the evolutionary success of the Lepidoptera because angiosperms provide an enormous range of niches for ecological speciation to take place. By contrast, the basal lepidopteran lineage, Micropterigidae, remained unassociated with angiosperms since Jurassic times but nevertheless achieved a modest diversity in the Japanese Archipelago. We explored the causes and processes of diversification of the Japanese micropterigid moths by performing molecular phylogenetic analysis and extensive ecological surveying. Phylogenetic analysis recovered a monophyletic group of approximately 25 East Asian endemic species that feed exclusively on the liverwort Conocephalum conicum, suggesting that niche shifts hardly played a role in their diversification. Consistent with the low flying ability of micropterigid moths, the distributions of the Conocephalum specialists are each localized and allopatric, indicating that speciation by geographical isolation has been the major process shaping the diversity of Japanese Micropterigidae. To our knowledge, this is the largest radiation of herbivorous insects that does not accompany any apparent niche differentiation. We suggest that the significance of non-ecological speciation during the diversification of the Lepidoptera is commonly underestimated.