Molecular phylogeny, classification, biogeography and diversification patterns of a diverse group of moths (Geometridae: Boarmiini)

Phylogenomics and biogeography of sawflies and woodwasps (hymenoptera, symphyta)

Phylogenomic approaches have recently helped elucidate various insect relationships, but large-scale comprehensive analyses on relationships within sawflies and woodwasps are still lacking. Here, we infer the relationships and long-term biogeographic history of these hymenopteran groups using a large dataset of 354 UCE loci collected from 385 species that represent all major lineages. Early Hymenoptera started diversifying during the Early Triassic ∼249 Ma and spread all over the ancient supercontinent Pangaea. We recovered Xyeloidea as a monophyletic sister group to other Hymenoptera and Pamphilioidea as sister to Unicalcarida. Within the diverse family Tenthredinidae, our taxonomically and geographically expanded taxon sampling highlights the non-monophyly of several traditionally defined subfamilies. In addition, the recent removal of Athalia and related genera from the Tenthredinidae into the separate family Athaliidae is supported. The deep historical biogeography of the group is characterised by independent dispersals and re-colonisations between the northern (Laurasia) and southern (Gondwana) palaeocontinents. The breakup of these landmasses led to ancient vicariance in several Gondwanan lineages, while interchange across the Northern Hemisphere has continued until the Recent. The little-studied African sawfly fauna is likewise a diverse mixture of groups with varying routes of colonization. Our results reveal interesting parallels in the evolution and biogeography of early hymenopterans and other ancient insect groups.

Biogeography of Greater Antillean freshwater fishes, with a review of competing hypotheses

In biogeography, vicariance and long-distance dispersal are often characterised as competing scenarios. However, they are related concepts, both relying on collective geological, ecological, and phylogenetic evidence. This is illustrated by freshwater fishes, which may immigrate to islands either when freshwater connections are temporarily present and later severed (vicariance), or by unusual means when ocean gaps are crossed (long-distance dispersal). Marine barriers have a strong filtering effect on freshwater fishes, limiting immigrants to those most capable of oceanic dispersal. The roles of vicariance and dispersal are debated for freshwater fishes of the Greater Antilles. We review three active hypotheses [Cretaceous vicariance, Greater Antilles-Aves Ridge (GAARlandia), long-distance dispersal] and propose long-distance dispersal to be an appropriate model due to limited support for freshwater fish use of landspans. Greater Antillean freshwater fishes have six potential source bioregions (defined from faunal similarity): Northern Gulf of México, Western Gulf of México, Maya Terrane, Chortís Block, Eastern Panamá, and Northern South America. Faunas of the Greater Antilles are composed of taxa immigrating from many of these bioregions, but there is strong compositional disharmony between island and mainland fish faunas (>90% of Antillean species are cyprinodontiforms, compared to <10% in Northern Gulf of México and Northern South America, and ≤50% elsewhere), consistent with a hypothesis of long-distance dispersal. Ancestral-area reconstruction analysis indicates there were 16 or 17 immigration events over the last 51 million years, 14 or 15 of these by cyprinodontiforms. Published divergence estimates and evidence available for each immigration event suggests they occurred at different times and by different pathways, possibly with rafts of vegetation discharged from rivers or washed to sea during storms. If so, ocean currents likely provide critical pathways for immigration when flowing from one landmass to another. On the other hand, currents create dispersal barriers when flowing perpendicularly between landmasses. In addition to high salinity tolerance, cyprinodontiforms collectively display a variety of adaptations that could enhance their ability to live with rafts (small body size, viviparity, low metabolism, amphibiousness, diapause, self-fertilisation). These adaptations likely also helped immigrants establish island populations after arrival and to persist long term thereafter. Cichlids may have used a pseudo bridge (Nicaragua Rise) to reach the Greater Antilles. Gars (Lepisosteidae) may have crossed the Straits of Florida to Cuba, a relatively short crossing that is not a barrier to gene flow for several cyprinodontiform immigrants. Indeed, widespread distributions of Quaternary migrants (Cyprinodon, Gambusia, Kryptolebias), within the Greater Antilles and among neighbouring bioregions, imply that long-distance dispersal is not necessarily inhibitory for well-adapted species, even though it appears to be virtually impossible for all other freshwater fishes.

Larval polyphagy of Cataspilatesmarceloi (Lepidoptera, Geometridae), a Neotropical geometrid moth with flightless females

Surveys in the arid shrubland of the central Andes revealed larval polyphagy for Cataspilatesmarceloi Vargas, 2022 (Lepidoptera, Geometridae, Ennominae, Boarmiini), a geometrid moth with flightless females. This discovery suggests that, as well as in the Holarctic fauna, larval polyphagy would have been important for the evolution of flightlessness among Neotropical geometrid moths of the tribe Boarmiini.

Morphological changes in female reproductive organs in the African monarch butterfly, host to a male-killing Spiroplasma

Background

Sexual selection and conflicts within and between sexes promote morphological diversity of reproductive traits within species. Variation in the morphology of diagnostic reproductive characters within species offer an excellent opportunity to study these evolutionary processes as drivers of species diversification. The African monarch, Danaus chrysippus (Linnaeus, 1758), is widespread across Africa. The species is polytypic, with the respective geographical ranges of the four colour morphs only overlapping in East Africa. Furthermore, some of the populations host an endosymbiotic bacterium, Spiroplasma, which induces son-killing and distorts the local host population sex-ratio, creating sexual conflicts between the females seeking to optimize their fecundity and the limited mating capacity of the rare males.

Methods

We dissected females from Kenya, Rwanda and South Africa, where Spiroplasma vary in presence and prevalence (high, variable and absent, respectively), and conducted microscopy imaging of their reproductive organs. We then characterized the effect of population, female body size, and female mating status, on the size and shape of different genitalia characters of the D. chrysippus female butterflies.

Results

We showed that although the general morphology of the organs is conserved in D. chrysippus, female genitalia vary in size and shape between and within populations. The virgin females have smaller organs, while the same organs were expanded in mated females. Females from highly female-biased populations, where the male-killing Spiroplasma is prevalent, also have a larger area of their corpus bursae covered with signa structures. However, this pattern occurs because a larger proportion of the females remains virgin in the female-biased populations rather than because of male depletion due to the symbiont, as males from sex-ratio distorted populations did not produce significantly smaller nutritious spermatophores.

Integrative taxonomic revision of the African taxa of the Racotis Moore, 1887 generic complex (Lepidoptera, Geometridae, Ennominae, Boarmiini)

The Afrotropical taxa of the Racotis s.l. generic complex are revised utilising integrative taxonomical methods. Based on the evaluation of genital morphology and analyses of DNA barcodes, a new genus, Afroracotis gen. n. is established to include the Afrotropical "Racotis" species. The new genus is subdivided into 5 subgenera: Afroracotis subgen. n., Herbuloracotis subgen. n., Rwandaracotis subgen. n., Zebracotis subgen. n. and Sokokeracotis subgen. n.. A new monotypic genus is described to include Boarmia ugandaria Swinhoe, 1904 which was combined earlier with the genus Chorodna and recently with Racotis: Chorocotis gen. n.. Two species formerly assigned to Cleora are moved to Afroracotis: A. albitrigonis (Prout, 1927) comb. n., A. atriclava (Prout, 1926) comb. n.. Two species are transferred from Racotis to Colocleora: C. breijeri (Prout, 1922) comb. n., C. incauta (Prout, 1916) comb. n.. Seventeen new Afroracotis species (A. aliena, A. stadiei, A. violetteae, A. fiebigi, A. turlini, A. dargei, A. longicornuta, A. aristophanousi, A. muscivirens, A. chaineyi, A. lydiae, A. smithi, A. ochsei, A. milesi, A. helicalis, A. takanoi and A. staudei spp. n.) and 5 new subspecies (A. squalida thomensis, A. argillacea morettoi, A. longicornuta congolana, A. longicornuta ugandana and A. lydiae orientalis sspp. n.) are described, totalling 27 species and 8 subspecies contained in the genus Afroracotis. Adults and genitalia of all taxa are illustrated in 210 colour and 129 black and white figures demonstrating the intraspecific variability. The distribution of all taxa is illustrated in 6 dot maps. The results of the genetic analyses are figured in four phylograms.

The genome sequence of the Dotted Border, Agriopis marginaria (Fabricius, 1776)

We present a genome assembly from an individual male Agriopis marginaria (the Dotted Border, Arthropoda; Insecta; Lepidoptera; Geometridae). The genome sequence is 500.9 megabases in span. Most of the assembly is scaffolded into 29 chromosomal pseudomolecules, including the assembled Z sex chromosome. The mitochondrial genome has also been assembled and is 16.9 kilobases in length. Gene annotation of this assembly on Ensembl identified 12,443 protein coding genes.

Flightless Females in the Neotropical Moth Genus Cataspilates Warren (Lepidoptera: Geometridae) †

Although adults are winged and able to fly in most Lepidoptera species, they are apterous or brachypterous and unable to fly in others, such as the flightless females of some geometrid moths. Records of flightless females in the highly diverse and widespread tribe Boarmiini (Geometridae: Ennominae) are mainly restricted to some Nearctic and Palearctic genera. The aim of this study is to provide the first record of flightless females for Cataspilates Warren, 1897, a Boarmiini genus endemic to the Neotropical Region, through the description of Cataspilates marceloi sp. nov. from the arid highlands of the western slopes of the Andes of northern Chile. DNA barcodes confirmed the conspecificity of brachypterous females and winged males reared from larvae collected on the native shrub Adesmia spinosissima (Fabaceae). This contribution represents the first female description for Cataspilates and provides a new opportunity to improve the understanding of the evolution of flightlessness in geometrid moths.

Enhanced Resolution of Evolution and Phylogeny of the Moths Inferred from Nineteen Mitochondrial Genomes

The vast majority (approximately 90%) of Lepidoptera species belong to moths whose phylogeny has been widely discussed and highly controversial. For the further understanding of phylogenetic relationships of moths, nineteen nearly complete mitochondrial genomes (mitogenomes) of moths involved in six major lineages were sequenced and characterized. These mitogenomes ranged from 15,177 bp (Cyclidia fractifasciata) to 15,749 bp (Ophthalmitis albosignaria) in length, comprising of the core 37 mitochondrial genes (13 protein-coding genes (PCGs) + 22 tRNAs + two rRNAs) and an incomplete control region. The order and orientation of genes showed the same pattern and the gene order of trnM-trnI-trnQ showed a typical rearrangement of Lepidoptera compared with the ancestral order of trnI-trnQ-trnM. Among these 13 PCGs, ATP8 exhibited the fastest evolutionary rate, and Drepanidae showed the highest average evolutionary rate among six families involved in 66 species. The phylogenetic analyses based on the dataset of 13 PCGs suggested the relationship of (Notodontidae + (Noctuidae + Erebidae)) + (Geometridae + (Sphingidae + Drepanidae)), which suggested a slightly different pattern from previous studies. Most groups were well defined in the subfamily level except Erebidae, which was not fully consistent across bayesian and maximum likelihood methods. Several formerly unassigned tribes of Geometridae were suggested based on mitogenome sequences despite a not very strong support in partial nodes. The study of mitogenomes of these moths can provide fundamental information of mitogenome architecture, and the phylogenetic position of moths, and contributes to further phylogeographical studies and the biological control of pests.

In search of ecological determinants of fungal infections: A semi‐field experiment with folivorous moths

Natural enemies shape the fate of species at both ecological and evolutionary time scales. While the effects of predators, parasitoids, and viruses on insects are well documented, much less is known about the ecological and evolutionary role of entomopathogenic fungi. In particular, it is unclear to which extent may the spatiotemporal distribution patterns of these pathogens create selective pressures on ecological traits of herbivorous insects. In the present study, we reared three lepidopteran species in semi‐natural conditions in a European hemiboreal forest habitat. We studied the probability of the insects to die from fungal infection as a function of insect species, food plant, study site, (manipulated) condition of the larvae, and the phenological phase. The prevalence of entomopathogenic fungi remained low to moderate with the value consistently below 10% across the subsets of the data while as many as 23 fungal species, primarily belonging to the families Cordycipitaceae, Aspergillaceae, and Nectriaceae, were recorded. There were no major differences among the insect species in prevalence of the infections or in the structure of associated fungal assemblages. The family Cordycipitaceae, comprising mainly obligatory entomopathogens, dominated among the pathogens of pupae but not among the pathogens of larvae. Overall, there was evidence for a relatively weak impact of the studied ecological factors on the probability to be infected by a fungal pathogen; there were no effects of food plant, study site, or phenology which would be consistent over the study species and developmental stages of the insects. Nevertheless, when the prevalence of particular fungal taxa was studied, Akanthomyces muscarius was found infecting insects fed with leaves of only one of the food plant, Betula spp. Feeding on a particular plant taxon can thus have specific fitness costs. This demonstrates that fungus‐mediated effects on insect life history traits are possible and deserve attention.

A supertree of Northern European macromoths

Ecological and life-history data on the Northern European macromoth (Lepidoptera: Macroheterocera) fauna is widely available and ideal for use in answering phylogeny-based research questions: for example, in comparative biology. However, phylogenetic information for such studies lags behind. Here, as a synthesis of all currently available phylogenetic information on the group, we produce a supertree of 114 Northern European macromoth genera (in four superfamilies, with Geometroidea considered separately), providing the most complete phylogenetic picture of this fauna available to date. In doing so, we assess those parts of the phylogeny that are well resolved and those that are uncertain. Furthermore, we identify those genera for which phylogenetic information is currently too poor to include in such a supertree, or entirely absent, as targets for future work. As an aid to studies involving these genera, we provide information on their likely positions within the macromoth tree. With phylogenies playing an ever more important role in the field, this supertree should be useful in informing future ecological and evolutionary studies.

Early cellular development induced by ecdysteroid in sex-specific wing degeneration of the wingless female winter moth

The winter moth, Nyssiodes lefuarius, exhibits striking sexual dimorphism in wing form; males have functional wings of normal size, whereas females lack wings. We previously found that the steroid hormone 20-hydroxyecdysone (20E) triggered massive programmed cell death (PCD) only in the female pupal wing epithelium; however, when and how early sexual trait development of the pupal wings is initiated during pupal-adult metamorphosis remains obscure. To clarify the detailed morphological changes and mechanisms underlying early sexual trait development and cell death, we examined the effects of 20E on early ultrastructural and histological changes in the pupal wing epithelium of both sexes. Before the onset of adult differentiation, no morphological differences were observed in the epithelial cells of both sexes at an ultrastructural level. When 5.4 µg of 20E was injected into pupae of both sexes at 15 days after the onset of pupation, retraction of the wing epithelium from the pupal cuticle was initiated at day 2 after 20E injection in both sexes. Although overt degeneration of wing tissue was not still obvious, apoptotic body-like structures and auto-phagosomes were visible at day 3 after 20E injection in females, whereas development of scale precursor cells started on day 4 after injection in males. Our results suggest that (1) the injection of 20E induced sexually dimorphic changes in the pattern of organelle distribution in wing epithelial cells, and (2) abnormally shaped mitochondria in the cytoplasm of the female wing epithelium might be involved in the PCD that occurs during wing tissue degeneration.

First report of Meris paradoxa Rindge (Geometridae: Ennominae) in the central mountains of Mexico, description of its female and a comparison of caterpillar variation among kin

Meris paradoxa Rindge, thought to be restricted to southeastern Arizona, is documented in Mexico for the first time. Previously described only from males, we provide the first description of the female from specimens collected as caterpillars and reared to adults. We find female M. paradoxa to have a normal haustellum; an external diagnostic character for this species previously only confirmed in conspecific males. Female genitalia of M. paradoxa are found similar to other Meris, but the absence of a sclerotized signum (present in congeners) may prove autapomorphic. Natural history information for the genus is discussed in light of new data reported here for Mexican M. paradoxa.

Degenerated, Undifferentiated, Rearranged, Lost: High Variability of Sex Chromosomes in Geometridae (Lepidoptera) Identified by Sex Chromatin

Sex chromatin is a conspicuous body that occurs in polyploid nuclei of most lepidopteran females and consists of numerous copies of the W sex chromosome. It is also a cytogenetic tool used to rapidly assess the W chromosome presence in Lepidoptera. However, certain chromosomal features could disrupt the formation of sex chromatin and lead to the false conclusion that the W chromosome is absent in the respective species. Here we tested the sex chromatin presence in 50 species of Geometridae. In eight selected species with either missing, atypical, or normal sex chromatin patterns, we performed a detailed karyotype analysis by means of comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The results showed a high diversity of W chromosomes and clarified the reasons for atypical sex chromatin, including the absence or poor differentiation of W, rearrangements leading to the neo-W emergence, possible association with the nucleolus, and the existence of multiple W chromosomes. In two species, we detected intraspecific variability in the sex chromatin status and sex chromosome constitution. We show that the sex chromatin is not a sufficient marker of the W chromosome presence, but it may be an excellent tool to pinpoint species with atypical sex chromosomes.