In search for the unlikely: Leaf-mining caterpillars (Gracillariidae, Lepidoptera) from Upper Cretaceous and Eocene ambers

Fossil leaf-mining caterpillars from amber are firstly described as the new species Phyllocnistis cretacea from Upper Cretaceous Myanmar amber and Phyllonorycter inopinata from Eocene Baltic amber. Both show typical traits of leaf-miners, and specifically, of later instars of caterpillars of their respective genera. The findings give further evidence for these being quite old and conservative genera of Gracillariidae. These are basal Ditrysia which retained the larval feeding and mining live mode. The findings also represent direct fossil evidence of individual stages of hypermetamorphosis known from extant Gracillariidae. The finds from the Upper Cretaceous and their putative identifications give direct evidence for a minimal geological age for the genus Phyllocnistis (Phyllocnistinae) and, by indirect conclusion based on their divergence, also for the genus Phyllonorycter in a sister clade (Lithocolletinae). It also predates mining habit closer to the time of radiation of their angiospermous host plants.

Discovery of the new Coptotriche species in China revealed two novel host-plant families and host-plant orders for Tischeriidae, a family of stenophagous, leaf-mining lepidopterans

The article describes three new species of Coptotriche Walsingham, 1890 from China and adjacent northern Vietnam: C. camptotheca Xu & Dai, sp. nov. feeding on Camptotheca acuminata Decne. (Nyssaceae); C. turpinia Xu & Dai, sp. nov. feeding on Turpinia arguta (Lindl.) Seem. (Staphyleaceae); and C. asiana Diškus & Stonis, sp. nov. The latter appeared to be a narrow oligophagous species feeding on various Symplocos Jacq.: S. sumuntia Buch.-Ham. ex D. Don, S. poilanei Guill., and Symplocos glauca (Thunb.) Koidz. (Symplocaceae). Nyssaceae and Staphyleaceae are novel host-plant families of Tischeriidae. The new species are illustrated with photographs of adults, male and female genitalia, and leaf mines. The article also briefly discusses about the proportion of monophagous and oligophagous species of Tischeriidae.

The First Eight Mitogenomes of Leaf-Mining Dactylispa Beetles (Coleoptera: Chrysomelidae: Cassidinae) Shed New Light on Subgenus Relationships

The taxonomic classification of Dactylispa, a large genus of leaf-mining beetles, is problematic because it is currently based on morphology alone. Here, the first eight mitochondrial genomes of Dactylispa species, which were used to construct the first molecular phylogenies of this genus, are reported. The lengths of the eight mitogenomes range from 17,189 bp to 20,363 bp. All of the mitochondrial genomes include 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and 1 A + T-rich region. According to the nonsynonymous/synonymous mutation ratio (Ka/Ks) of all PCGs, the highest and the lowest evolutionary rates were found for atp8 and cox1, respectively, which is a common phenomenon among animals. According to relative synonymous codon usage, UUA(L) has the highest frequency. With two Gonophorini species as the outgroup, mitogenome-based phylogenetic trees of the eight Dactylispa species were constructed using maximum likelihood (ML) and Bayesian inference (BI) methods based on the PCGs, tRNAs, and rRNAs. Two DNA-based phylogenomic inferences and one protein-based phylogenomic inference support the delimitation of the subgenera Dactylispa s. str. and Platypriella as proposed in the system of Chen et al. (1986). However, the subgenus Triplispa is not recovered as monophyletic. The placement of Triplispa species requires further verification and testing with more species. We also found that both adult body shape and host plant relationship might explain the subgeneric relationships among Dactylispa beetles to a certain degree.

Oldest Leaf-Mine Trace Fossil from East Asia and Stoichiometric Footprint: 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 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 blotch containing spheroidal particles – demonstrating larval development. The shapes of these mines generally resemble those of nepticuloid moths, although they are absent from extant fern-mining assemblages. 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 (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.

A new species of Micrurapteryx (Lepidoptera, Gracillariidae) feeding on Thermopsis lanceolata (Fabaceae) in southern Siberia and its hymenopterous parasitoids

A new species of leaf-mining moth described here as Micrurapteryx baranchikovi Kirichenko, Akulov & Triberti, sp. nov. was detected in large numbers feeding on Thermopsis lanceolata (Fabaceae) in the Republic of Khakassia (Russia) in 2020. A morphological diagnosis of adults, bionomics and DNA barcoding data of the new species are provided. The developmental stages (larva, pupa, adult), male and female genitalia, as well as the leaf mines and the infestation plot in Khakassia are illustrated; the pest status of the new species in the studied region is discussed. Additionally, parasitism rate was estimated, the parasitoid wasps reared from pupae of the new species were identified (morphologically and genetically) and illustrated . Among them, one ichneumonid, Campoplex sp. aff. borealis (Zetterstedt) and two braconids, Agathis fuscipennis (Zetterstedt) and Illidops subversor (Tobias et Kotenko), are novel records for the Republic of Khakassia. Furthermore, they are all documented as parasitoids of Gracillariidae for the first time. The DNA barcode of A. fuscipennis is newly obtained and can be used as a reference sequence for species identification.

Most trumpet moths don’t feed on plants of the nettle family but Paratischeria does: the first discovery of Tischeriidae (Lepidoptera) on Urticaceae in Asia

This is the first record of Urticaceae-feeding trumpet moths (Tischeriidae) from Asia. We describe Paratischeria boehmerica Diškus & Stonis, sp. nov. and P. grossa Diškus & Stonis, sp. nov., two distinctive new species of Tischeriidae recently discovered from Laos, South East Asia, feeding on plants of the nettle family. Urticaceae is a rare host-plant family for leaf-mining Tischeriidae worldwide. The new species are illustrated with photographs of the adults, male and female genitalia, and the leaf mines.

High Incidence of Related Wolbachia across Unrelated Leaf-Mining Diptera

The maternally inherited endosymbiont, Wolbachia pipientis, plays an important role in the ecology and evolution of many of its hosts by affecting host reproduction and fitness. Here, we investigated 13 dipteran leaf-mining species to characterize Wolbachia infections and the potential for this endosymbiont in biocontrol. Wolbachia infections were present in 12 species, including 10 species where the Wolbachia infection was at or near fixation. A comparison of Wolbachia relatedness based on the wsp/MLST gene set showed that unrelated leaf-mining species often shared similar Wolbachia, suggesting common horizontal transfer. We established a colony of Liriomyza brassicae and found adult Wolbachia density was stable; although Wolbachia density differed between the sexes, with females having a 20-fold higher density than males. Wolbachia density increased during L. brassicae development, with higher densities in pupae than larvae. We removed Wolbachia using tetracycline and performed reciprocal crosses between Wolbachia-infected and uninfected individuals. Cured females crossed with infected males failed to produce offspring, indicating that Wolbachia induced complete cytoplasmic incompatibility in L. brassicae. The results highlight the potential of Wolbachia to suppress Liriomyza pests based on approaches such as the incompatible insect technique, where infected males are released into populations lacking Wolbachia or with a different incompatible infection.

Relationships between pest density and associated leaf necrosis for an invasive leaf-mining weevil, Orchestes fagi L., on American beech (Fagus grandifolia Ehrh.)

Pest density-plant damage relationships are essential guides for decision-making in Integrated Pest Management. In this article, we established pest density-leaf damage relationships for the beech leaf-mining weevil,<i></i> Orchestes fagi <i></i>(L.) (formerly <i></i>Rhynchaenus fagi<i></i>, Coleoptera: Curculionidae) in its invasive range of Nova Scotia, Canada. Outbreaks of<i> O. fagi</i> cause tree-wide leaf necrosis in American beech (<i>Fagus grandifolia</i> Ehrh.), which can eventually result in tree mortality. In 2014 and 2016, we collected weekly samples in stands with American beech and assessed leaves for densities during different life stages (eggs, larvae, and pupae), population proxy measures (adult feeding damage, egg slits, and larval galleries), and percent necrosis. In general, feeding damage and leaf necrosis plateaued soon after end of budburst, but before larval mine expanded. This strongly suggested that leaf necrosis may be linked to damage caused by adults or mine initiation rather than that caused by larval mine expansion and gallery development. Density of <i>O. fagi</i> per leaf for life stages and population proxies all significantly explained ~ 42–81% of the variation in end-of season percent leaf necrosis. Results from this study provide a variety of relationships that could be used in both short- and long-term monitoring efforts for <i>O. fagi</i>.