Gene Flow and Diversification in Himalopsyche martynovi Species Complex (Trichoptera: Rhyacophilidae) in the Hengduan Mountains

Abstract

The Hengduan Mountains are one of the most species-rich mountainous areas in the world. The origin and evolution of such a remarkable biodiversity are likely to be associated with geological or climatic dynamics, as well as taxon-specific biotic processes (e.g., hybridization, polyploidization, etc.). Here, we investigate the mechanisms fostering the diversification of the endemic Himalopsyche martynovi complex, a poorly known group of aquatic insects. We used multiple allelic datasets generated from 691 AHE loci to reconstruct species and RaxML phylogenetic trees. We selected the most reliable phylogenetic tree to perform network and gene flow analyses. The phylogenetic reconstructions and network analysis identified three clades, including H. epikur, H. martynovi sensu stricto and H. cf. martynovi. Himalopsyche martynovi sensu stricto and H. cf. martynovi present an intermediate morphology between H. epikur and H. viteceki, the closest known relative to the H. martynovi-complex. The gene flow analysis revealed extensive gene flow among these lineages. Our results suggest that H. viteceki and H. epikur are likely to have contributed to the evolution of H. martynovi sensu stricto and H. cf. martynovi via gene flow, and thus, our study provides insights in the diversification process of a lesser-known ecological group, and hints at the potential role of gene flow in the emergence of biological novelty in the Hengduan Mountains.

A preliminary molecular phylogeny of the family Hydroptilidae (Trichoptera): an exploration of combined targeted enrichment data and legacy sequence data

“…We used the Trichoptera probe set published in Deng et al (2021) for the targeted enrichment analyses. Following DNA extraction, quantification, targeted enrichment, library preparation, and DNA sequencing were conducted off-site by Rapid Genomics.…”

“…It allows for sequencing across many hundreds of genes, even for specimens with degraded DNA ( Lemmon et al 2012 ). Recently, Deng and colleagues applied this approach to the trichopteran genus Himalopsyche ( Deng et al 2021 ). This preliminary study acts as a proof-of-concept that targeted enrichment sequence data using the previously published Trichoptera probe set can be successfully obtained from hydroptilid specimens and, when used in tree construction, can successfully recover expected clades, and produce a phylogeny with high support values.…”

The impact of sequencing depth and relatedness of the reference genome in population genomic studies: A case study with two caddisfly species (Trichoptera, Rhyacophilidae, Himalopsyche)

“…Therefore, comprehensively exploring the influence of reference choice and sequencing depth on downstream analyses is urgently needed, particularly for insects. In this study, we will evaluate the effects of the reference genome and sequencing depth on a genus of caddisflies, for which we already have significant molecular and taxonomic data (Deng et al, 2021 ; Heckenhauer et al, 2022 ).…”

Holotype sequencing of Silvatares holzenthali Rázuri-Gonzales, Ngera & Pauls, 2022 (Trichoptera, Pisuliidae)

“…Especially in variable taxa or clades with high levels of cryptic diversity, anchoring species delimitation analyses, taxonomic work or evolutionary studies on the genetic make-up of the name-bearing specimens can be extremely helpful. Genome wide data have been used to help delimit closely related species in Trichoptera (e.g., Deng et al 2021 ); however, since the holotypes of the species in question were not among the analyzed specimens, the nomenclature and taxonomy of each species could not be fully resolved. This case highlights the value of sequencing the genome of the primary type.…”