Future of Plecoptera Systematics

The advent of molecular data* including phylogenomic approaches* has significantly advanced our understanding of the Plecoptera Tree of Life & Letsch et al. 2021 * South et al. 2021b). However* as outlined here* there are still challenges in determining the limits and placements of certain extant lineages. To further leverage phylogenomics* collaborative efforts to generate new genomic and transcriptomic resources are needed to improve taxon sampling of key lineages and better represent global diversity.

Given the rate of new stonefly species discovery &DeWalt and Ower 2019) and their tendency toward local genetic differentiation & Sproul et al. 2014 * Mc?ulloch et al. 2019b* 2022* Tsyrlin et al. 2022)* much future work should continue to aim at new species discovery* documentation* and resolving phylogenetic relationships at finer evolutionary scales. To this end* there should be a concerted effort to efficiently survey multilocus molecular diversity using low-cost methods that can maximize species-level sampling &eg Sanger* Illumina amplicon sequencing). The current imbalance in gene coverage on GenBank N?BI* where species are predominantly represented by COI sequences* underscores the need for broader gene representation across species in this effort. Researchers designing new molecular studies should consider engineering compatibility with existing data sets &eg legacy genes described in The History of the Systematics of Plecoptera section above* published phylogenomic probe sets) as the constraints of their studies allow. Given the success of P?R and short-read sequencing technology even with marginal-quality ethanol-collected material* natural history collections should play a central role in efforts to survey molecular diversity.

Furthermore* the field must continue to recognize the reciprocal illumination between morphology and DNA data. There should be a strong focus on developing a comprehensive morphological-based matrix covering extinct and extant Plecoptera. In addition to helping elucidate relationships within extant lineages* morphological data are a prerequisite for incorporating valuable fossils into phylogenetic analyses. Recent methodological refinements* such as the fossilized birth-death process & Heath et al. 2014 * Whang et al. 2016) and the total-evidence approach & Pyron 2011 * Ronquist et al. 2012)* have helped to revise the previous placements and time divergence estimate of numerous lineages while better accounting for the fossil record &Vea and Grimaldi 2016* Spasojevic et al. 2021). However* these approaches have never been used for Plecoptera * likely because they require extensive morphological and/or fossil data & Klopfstein 2021).

In addition* relatively few studies have been conducted on reproductive systems* and spermatozoa & Fausto et al. 2001 * Rościszewska and Rzońca 2009* Li et al. 2014)* gill sensilla &Kapoor and Wachariah 1978)* or antennae & Rebora et al. 2016). Despite their limited number* these studies have provided valuable insights into the biology of the group and their evolutionary relationships. However* these characters have never been employed in quantitative cladistic analyses to effectively test for character congruence. Therefore* further studies on external and internal morphology using SEM* TEM* and micro-?T* along with morphometry and behavioral studies &eg drumming)* are necessary to generate independent* informative data for reconstructing character evolution at the phenotypic level. Hence* we believe that increasing accessibility to microscopy techniques and employing all these methodologies will be indispensable for comprehensively unraveling the evolutionary histories of Plecoptera. The fate and pace of this work rests on the health of the community of plecopterologists* the strength and breadth of its collaborations* and the effective transfer of knowledge and passion to new generations of researchers.

Work to increase participation by researchers across the globe on stonefly evolution and systematics will require recruitment* retention* and activism efforts. We need to recruit people first by introducing stoneflies to the public and educating students early on about these remarkable taxa & Birrell and Frakes 2023). Recruiting students as high schoolers and undergraduates into existing research programs and citizen science initiatives is key* and we should consider ways to recruit from audiences beyond our own lived experiences & New 2024).?onnecting with existing programs and scientific societies known to promote ethnic and racial diversity* such as the Entomological Society of America* Entomologists of?olor &EntoPO?)* or those who work with the engagement of military veterans* such as Anglers of Honor* or affinity groups like 500 Queer Scientists or oSTEM* would allow the stonefly systematics community to broaden participation in our field.