Addressing biodiversity knowledge shortfalls in New World Helicopsychidae (Insecta, Trichoptera): Potential distribution, environmental gradients, and identification of conservation and research priority areas

PLOS One | https://doi.org/10.1371/journal.pone.0327580 July 28, 2025 9 / 22 Four correlative modelling algorithms were used: Bioclim [56], Domain [57], Generalized Linear Model (GLM) [58], and the Vector Support Machine (SVM) [59]. As absence data is not predicted or lacks accuracy given the bias/scarce sam- pling scenario, presence/pseudo-absence models will be used. We randomly generated pseudo-absence points (1:1 ratio for the occurrence points) [60], through the ‘randomPoints’ function of the ‘dismo’ package (https://cran.r-project.org/pack- age=dismo) in the R environment. Data partitioning was randomly performed in 70% for training and 30% for testing the models. The repeatability of the models (200 times) was used to increase the robustness of the result. After the models were evaluated using the Area Under the Curve (AUC) [61] method, which only models with values of AUC > 80% were used for the construction of suitability maps. Finally, we used the default limits of presence and absence for the construc- tion of the suitability maps. Results Biodiversity knowledge shortfalls In the New World, the Helicopsyche species richness remains largely underestimated, with estimates suggesting up to 571 species (error = 142), indicating that approximately 75% of the species remain undescribed (Table 2). The subgenus H. (Cochliopsyche) comprises 17 valid species, all distributed in the Neotropics, particularly in the Brazilian subregion (Fig 1B). Estimates project 36 species (error = 16), with 53% remaining undescribed (Table 2). The first species was described

by Ulmer in 1905, followed by significant contributions from Flint [62–64]. Johanson’s revision added 12 species, and after a 20-year gap, Oláh & Oláh [65] described a new species from Ecuador (Fig 2C). The subgenus H. (Feropsyche) includes 129 valid species, widely distributed across tropical regions of the Nearctic, Neotropical and Patagonian regions, with the highest richness in the Brazilian subregion (125 species) (Fig 1G). Estimates suggest 553 species (error = 152), with 77% remaining undescribed (Table 2). In the past 20 years, about 40% of H. (Feropsyche) species were described, averaging five species annually, compared to two species per year from 1840 to 1999 (Fig 2D). Approximately 79% of Helicopsyche species have restricted distributional records (< 10 records), with around 70% occurring only in type localities or adjacent areas, such as the same stream (Fig 2A and B; S1 Table). The species with the widest distribution are H. (Cochliopsyche) opalescens Flint, 1972, with 41 records across 147.3 km², and H. (Feropsy- che) borealis (Hagen, 1861), with 48 records across 211.03 km² (Fig 2A and B). In H. (Cochliopsyche), 58% of species have restricted records, with 47% limited to type localities or adjacent areas (Fig 2A; S1 Table). In contrast, H. (Feropsy- che) shows a higher percentage of species with restricted records, reaching 88%, and 72% of these species are confined to type localities or adjacent areas (Fig 2B; S1 Table). Immature stages are documented for 20 valid species (15%), and female adults are described for 30 valid species

(24%). In H. (Cochliopsyche), adult males of all species are described. However, immature stages are known for only one Table 2. Summary of the estimation of species richness in the new world based on incidence data with the CHAO2, second order jackknife (JACK2) estimators. Chao2 Jacknife2 Average Estimation of unknown species Helicopsyche (Cochliopsyche) Species estimates 36 34 35 18 Error 16 4 10 Helicopsyche (Feropsyche) Species estimates 553 310 431 302 Error 152 33 92 New World Helicopsyche Species estimates 571 343 457 311 Error 142 35 88 https://doi.org/10.1371/journal.pone.0327580.t002