Unique among high passes: Phylogenetic inferences from DNA barcoding of the butterfly fauna of Ladakh Trans-Himalaya, India

The butterfly assemblage of Ladakh Trans-Himalaya demands a thorough analysis of their population genetic structure owing to their typical biogeographic affinity and their adaptability to extreme cold-desert climates. No such effort has been taken till date, and in this backdrop, we created a barcode reference library of 60 specimens representing 23 species. Barcodes were generated from freshly collected leg samples using the Sanger sequencing method, followed by phylogenetic clade analyses and divergence calculation. Our data represents 22% of Ladakh's Rhopaloceran fauna with the novel barcode submission for six species, including one Schedule II species, Paralasa mani . Contrary to the 3% threshold rule, the interspecific divergence between two species pairs of typical mountain genus Hyponephele and Karanasa was found to be 2.3% and 2.2%, respectively. The addition of conspecific global barcodes revealed that most species showed little increase in divergence value, while a two-fold increase was noted in a few species. Bayesian clade clustering outcomes largely aligned with current morphological classifications, forming monophyletic clades of conspecific barcodes, with only minor exceptions observed for the taxonomically complicated genus Polyommatus and misidentified records of Aulocera in the database. We also observed variations within the same phylogenetic clades forming nested lineages, which may be attributed to the taxonomic intricacies present at the subspecies level globally, mostly among Eurasian species. Overall, our effort not only substantiated the effectiveness of DNA Barcoding for the identification and conservation of this climatically vulnerable assemblage but also highlighted the significance of deciphering the unique genetic composition among this geographically isolated population of Ladakh butterflies.

Use of an exotic host plant reduces viral burden in a native insect herbivore

Incorporation of exotic plants into the diets of native herbivores is a common phenomenon, influencing interactions with natural enemies and providing insight into the tritrophic costs and benefits of dietary expansion. We evaluated how use of an exotic plant, Plantago lanceolata, impacted immune performance, development and susceptibility to pathogen infection in the neotropical herbivore Anartia jatrophae (Lepidoptera: Nymphalidae). Caterpillars were reared on P. lanceolata or a native plant, Bacopa monnieri, and experimentally infected with a pathogenic virus, Junonia coenia densovirus. We found that virus-challenged herbivores exhibited higher survival rates and lower viral burdens when reared on P. lanceolata compared to B. monnieri, though immune performance and development time were largely similar on the two plants. These findings reveal that use of an exotic plant can impact the vulnerability of a native herbivore to pathogen infection, suggesting diet-mediated protection against disease as a potential mechanism facilitating the incorporation of novel resources.

Differentiation in the eastern Asian Periphyllus koelreuteriae (Hemiptera: Aphididae) species complex driven by climate and host plant

Divergent adaptation to different ecological conditions is regarded as important for speciation. For phytophagous insects, there is limited empirical evidence on species differentiation driven by climate and host plant. The recent application of molecular data and integrative taxonomic practice may improve our understanding of population divergence and speciation. Periphyllus koelreuteriae aphids feed exclusively on Koelreuteria (Sapindaceae) in temperate and subtropical regions of eastern Asia, and show morphological and phenological variations in different regions. In this study, phylogenetic and haplotype network analyses based on four genes revealed that P. koelreuteriae populations comprised three distinct genetic clades corresponding to climate and host plants, with the populations from subtropical highland regions and on Koelreuteria bipinnata host plants representing the most basal clade. These genetic lineages also showed distinct characteristics in terms of morphology and life cycle. The results indicate that P. koelreuteriae is a species complex with previously unrevealed lineages, whose differentiation may have been driven by climatic difference and host plant.

Phylogenetic analysis of the complete mitochondrial genome of the white peacock butterfly Anartia jatrophae saturata (Insecta: Lepidoptera: Nymphalidae)

The white peacock butterfly Anartia jatrophae saturata Staudinger, 1884 (Nymphalidae: Nymphalinae: Victorini), lives in the neotropics. Genome skimming with Illumina sequencing of A. jatrophae saturata allowed the assembly of a complete circular mitogenome of 15,297 bp, consisting of 81.4% AT nucleotides, 22 tRNAs, 13 protein-coding genes, two rRNAs, and a control region. Anartia jatrophae COX1 features an atypical start codon (CGA); ATP6, COX1, ND1, ND4, ND4L, ND5, and ND6 exhibit incomplete stop codons completed in the mRNA by the addition of 3' A residues. Contrary to previous phylogenetic hypotheses, phylogenetic reconstruction places A. jatrophae as sister to nymphalid tribe Nymphalini.