Supplementary material 1 from: Ríos-Touma B, Frandsen PB, Holzenthal RW, Houghton DC, Rázuri-Gonzales E, Pauls SU (2025) Preface: Proceedings of the 18th International Symposium on Trichoptera. In: Ríos-Touma B, Frandsen PB, Holzenthal RW, Houghton DC, Rázuri-Gonzales E, Pauls SU (Eds) Proceedings of the 18th International Symposium on Trichoptera. ZooKeys 1263: 1-19. https://doi.org/10.3897/zookeys.1263.177866

PROGRAM & ABSTRACTS 18th International Symposium on Trichoptera    Monday Tuesday Wednesday Thursday Friday July 1st July 2nd July 3rd July 4th July 5th 8:00-9:00 Registration Registration Registration Registration Moderator Ralph Holzenthal Steffen Pauls Paul Frandsen 9:00-9:20 Registration Monika Springer Simon Vitecek Deb Finn 9:20-9:40 opening sessions Monika Springer Simon Vitecek Deb Finn 9:40-10:00 opening sessions Monika Springer Simon Vitecek Deb Finn 10:00-10:30 Break Break Break Break Moderator Blanca Ríos-Touma Andrés Morabowen Isabella Errigo Tatiana Latorre 10:30-10:50 Andrea Encalada Ramírez Gerwin (Pauls) Orfinger 10:50-11:10 Andrea Encalada Dias (Vilarino) Gislason Chan (remote) 11:10-11:30 Andrea Encalada Quiteiro Houghton Kümmerlen (Pauls) 11:30-11:50 Holzenthal Frandsen 1 Latorre-Beltrán Robertson Group Photography 12:00-12:30 Lunch Break Lunch Break Lunch Break Lunch Break 12:30-12:50 Lunch Break Lunch Break Lunch Break Lunch Break 12:50-13:10 Lunch Break Lunch Break Lunch Break Lunch Break 13:10-13:30 Lunch Break Lunch Break Lunch Break Lunch Break 13:30-13:50 Lunch Break Lunch Break Lunch Break Lunch Break 13:50-14:00 Lunch Break Lunch Break Lunch Break Lunch Break Moderator Ernesto Rázuri-González David Tempelman Fabio Quinteiro Steffen Pauls 14:00-14:30 Errigo Ríos-Touma Rázuri Hussain 14:30-14:50 Jijon Mendez Morabowen Clossing Ceremony 14:50-15:10 Correa-Bedoya Rasmussen Frandsen 2 Clossing Ceremony 15:10-15:40 Break Break Break Break Moderator Mauricio Ramírez 15:40-16:10 Laudee Poster Session Poster Session 16:10-16:30 Ivanov Poster Session Poster Session 16:30-16:50 Solano-Ulate Poster Session Poster Session 16:50-17:10 Tempelman Poster Session Poster Session 17:00-17:20 Poster Session Poster Session 17:20-17:40 17:40-18:00 18:00-19:00 19:00-20:00 Symposium Dinner 20:00 onwards Excursion Welcome Reception SCHEDULE 18th International Symposium on Trichoptera Monday, July 1st Opening Session 8:00-9:20 Registration 9:20-10:00 Welcome addresses: Dr. Blanca Ríos-Touma, Docente Investigador and Convenor, Universidad de Las Américas, Dr. Gonzalo Mendieta, Rector, Universidad de Las Américas; announcements and general information. 10:00-10:30 Break Plenary Address Moderator, Blanca Ríos Touma 10:30-11:30 Dr. Andrea Encalada, Universidad San Francisco de Quito, Ecuador. Conserving Amazon’s Freshwater Health, Biodiversity and Connectivity Presentations 11:30-11:50 Ralph Holzenthal, The Trichoptera of Ecuador 12:00-14:00 Lunch Moderator, Ernesto Rázuri-Gonzales 14:00-14:30 Isabella Errigo, eDNA in the Neotropics: Testing its efficacy as a biomonitoring tool 14:30-14:50 Gabriella Jijón, Morphology outperforms DNA barcoding in identifying Trichoptera in Ecuadorian streams 14:50-15:10 Alejandra Correa-Bedoya, Temporal and spatial comparative analysis of taxonomic richness and functional diversity of Trichoptera in urban and rural waters of middle and lower Cauca Basin, Colombia 15:10-15:40 Break Moderator, Mauricio Ramírez 15:40-16:10 Pongsak Laudee, Species diversity of caddisflies (Insecta: Trichoptera) from lowland forest springs, Surat Thani Province, southern Thailand 16:10-16:30 Vladimir Ivanov, First data on Trichoptera of the Putorana Plateau (Northern Siberia) 16:30-16:50 Darha Solano-Ulate, Waterfalls as a reservoir for caddisfly larvae: exploring a poorly known habitat 16:50-17:10 David Templeman, Trichoptera and Citizen Science in the Netherlands Welcome Reception Universidad de Las Américas 17:40 1 Tuesday, July 2nd 8:00-9:00 Registration Plenary Address Moderator, Ralph Holzenthal 9:00-10:00 Prof. Monika Springer, Universidad de Costa Rica. Trichoptera studies: Perspectives from the Central American land bridge 10:00-10:30 Break Presentations Moderator, Andrés Morabowen 10:30-10:50 Mauricio Ramírez, Towards a robust phylogeny of Stactobiinae (Trichoptera: Hydroptilidae): synthesizing molecular and morphological data 10:50-11:10 Everton Dias (Albane Vilarino), Diversification and historical biogeography of long-horned caddisflies (Trichoptera: Leptoceridae) 11:10-11:30 Fabio Quinteiro, Exploring the Trichoptera in the Taxonomic Catalog of the Brazilian Fauna: recent progress and perspectives 11:30-11:50 Paul Frandsen, What do genes have to do with caddisfly silk? 12:00-14:00 Lunch Moderator, David Templeman 14:00-14:30 Blanca Ríos-Touma, Elevational biodiversity gradients in caddisflies from the tropical Andes 14:30-14:50 Patina Mendez, Growth and development of undergraduate Trichoptera researchers 14:50-15:10 Andrew Rasmussen, The Trichoptera fauna of Florida: diversity and distribution 15:10-15:40 Break 15:40-17:20 Poster Session 1 [Ali, Alvear, Costa, Del Castillo, Ge, Gerth, Kučinić, Maaskant, RázuriGonzales, Santana, Sganga, Villamarín] 2 Wednesday, July 3rd 8:00-9:00 Registration Plenary Address Moderator, Steffen Pauls 9:00-10:00 Dr. Simon Vitecek, University of Natural Resources and Life Sciences, Austria. The importance of taxonomy and systematics (again) and some future opportunities for Trichoptera research 10:00-10:30 Break Presentations Moderator, Isabella Errigo 10:30-10:50 Sonja Gerwin (Pauls), Elevational diversity of Rhyacophila (Trichoptera: Rhyacophilidae) in the Hengduan Shan 10:50-11:10 Gísli Már Gíslason, Relationship of Trichoptera species in Iceland with other North-Atlantic islands and the mainland of Europe 11:10-11:30 David Houghton, Analyzing adult Trichoptera to assess upstream disturbance: one (caddis) metric to rule them all? 11:30-11:50 Tatiana Latorre-Beltrán, Trichoptera dispersion: insights from lateral and longitudinal sampling 12:00-14:00 Lunch Moderator, Fabio Quinteiro 14:00-14:30 Ernesto Rázuri-Gonzales, The Trichoptera of Africa: New species, unknowns, and state-of-the-art 14:30-14:50 Andrés Morabowen, Landuse and elevation-driven changes in caddisfly assemblages in Neotropical streams in Ecuador 14:50-15:10 Paul Frandsen, Milne and Milne revisited: The evolution of caddisflies 15:10-15:40 Break 15:40-17:20 Poster Session 2 [Castañeda, Gallegos, Li, Majeed, Maaskant, Ramírez, Rázuri, Sganga, Stark, Thomson, Vimos, Watanabe] Symposium Dinner La Purísima, Quito Historic District 19:00 3 Thursday, July 4th 8:00-9:00 Registration Plenary Address Moderator, Paul Frandsen 9:00-10:00 Dr. Deb Finn, Missouri State University, USA. Stream networks, dispersal traits, and connectivity in mountain stream headwaters 10:00-10:30 Break Presentations Moderator, Tatiana Latorre-Beltrán 10:30-10:50 Alexander Orfinger, Larval taxonomy of the net-spinning caddisfly Cernotina truncona Ross, 1947 (Trichoptera: Polycentropodidae) 10:50-11:10 Yee Qi Chan, Trichoptera in Singapore: A first look 11:10-11:30 Mathias Kümmerlan (Steffen Pauls), Higher predicted climate-change vulnerability for spring-dwelling freshwater biota 11:30-11:50 Desiree Robertson, Caddisflies in hot water: a review of climate change studies related to Trichoptera 12:00-14:00 Lunch Moderator, Steffen Pauls 14:00-14:30 Zahid Hussain, Taxonomy and DNA barcodes of the family Philopotamidae (Trichoptera: Insecta) from India 14:30-15:10 Closing Session: Discussion of Proceedings, venue for 19th Symposium, information about excursions, announcements and other items; closing remarks Friday, July 5th Excursions Tandayapa Valley and Volcán Cotopaxi 4 PLENARY SPEAKERS Dr. Andrea C. Encalada Universidad San Francisco de Quito, Ecuador Andrea C. Encalada is a freshwater ecologist and professor at Universidad San Francisco de Quito and an Adjunct Professor at the University of North Carolina Chapel Hill. She got her Ph.D. from Cornell University, and since then, she has been working on stream and river research in tropical and temperate ecosystems. During the last 15 years, she has focused her research on river structure and function along elevation gradients in Andean-Amazon watersheds. She is particularly interested in climate change and other anthropogenic changes, including drying river networks, and how these impacts might alter populations, communities, and ecosystem processes. Conserving Amazon’s Freshwater Health, Biodiversity and Connectivity* The Amazon Basin, a cornerstone of global biodiversity and a critical regulator of ecological processes, is facing unprecedented threats from human activities and climate change. Amazonian freshwater ecosystems provide invaluable services, including water purification, transportation, energy, and food production, along with carbon sequestration and sustaining an immense biodiversity. The basin's hydrological cycles, driven by 'aerial rivers,' recycle a significant portion of water and contribute to continental rainfall patterns. These ecosystems host an incredible array of biodiversity; approximately 2,500 fish species inhabit these waters, many of which are endemic and vital to the livelihoods of local communities. In spite of this, many aquatic groups remain understudied. Despite their importance, Amazonian freshwater ecosystems are rapidly degrading due to pollution, deforestation, dam construction, mining, and climate change. The lack of sewage treatment facilities, substandard environmental practices in mining and oil extraction, and the construction of hydroelectric dams are fragmenting rivers, reducing biodiversity, and impairing ecosystem functions. These activities not only affect aquatic life but also have severe socio-economic impacts on Indigenous Peoples and Local Communities (IPLCs). To address these challenges, we advocate for the conservation, remediation, and restoration of Amazonian freshwater ecosystems. Key recommendations include halting dam construction and promoting sustainable energy by implementing a moratorium on new dam projects and investing in decentralized sustainable energy solutions that support local economies and preserve ecological functions. Enhancing water treatment and pollution control is essential, with urgent development of water treatment infrastructure, enforcement of pollution control policies, and promotion of the restoration of riparian vegetation to improve water quality and ecosystem health. Integrating climate change strategies into regional planning is crucial to maintaining ecosystem resilience and connectivity. Empowering IPLCs by recognizing and integrating Indigenous knowledge with scientific approaches enhances conservation efforts and promotes co-management of freshwater resources. Establishing transnational governance agreements and securing international financial support are vital for cohesive management and conservation efforts across the Amazon Basin. Investing in science and innovation supports cross-disciplinary research and technological innovations to better understand and mitigate stressors on freshwater ecosystems. By fostering collaborative efforts among scientists, policymakers, IPLCs, and stakeholders, we aim to develop robust strategies to protect and restore the health and connectivity of Amazonian freshwater ecosystems. This integrative approach is crucial for sustaining the ecological balance and ensuring the well-being of both the environment and local communities. Here, I will explore these vital topics and discuss how we can collectively contribute to a sustainable future for the Amazon Basin's freshwater ecosystems. *also presented on behalf of the Science Panel for the Amazon (SPA). 5 Dr. Deb Finn Missouri State University, United States Deb is a stream ecologist and associate professor at Missouri State University (USA). She spends most of her time attempting to mesh empirical research in streams with teaching and mentoring students, ultimately aiming to fill them with awe over “stream bugs”. She is fascinated by the phenomenal diversity of stream invertebrates that persists in such dynamic physical habitats, and much of her work addresses the roles of connectivity and habitat heterogeneity in conferring resistance and resilience to populations. Mountain headwaters have long been her focus, given the complex topography, hydrological heterogeneity, and physical isolation of headwaters at the tips of stream networks. She has worked in the tropical high Andes of Ecuador, the Alps and Pyrenees of Europe, the Great Dividing Range in SE Australia, and a number of mountainous regions of North America. Her favorite taxa are aquatic insects, particularly the EPT. Stream networks, dispersal traits, and connectivity in mountain stream headwaters Mountain streams are fascinating and informative systems for testing hypotheses about spatial distributions of organisms. Steep upstream-downstream environmental gradients, combined with water sources that can have strongly contrasting physicochemical characteristics, produce high levels of diversity over short spatial extents. High-elevation headwater branches of stream networks can also be isolated from one another by harsh terrestrial conditions at drainage divides, further promoting beta diversity. In this talk, I’ll start with a brief overview of my background and findings associated with aquatic insect diversity in mountain streams, and I’ll place strong emphasis on the role of dispersal limitation in generating spatial patterns of diversity in aquatic insects (definitely including caddisflies!) within and among stream networks. I’ll then present some case studies from both temperate and tropical high-mountain systems, and associated with both intraspecific diversity at the population-genetic level and interspecific patterns of community diversity. These case studies will suggest a few take-home messages, including: 1) At the single-species level, knowing something about dispersal/movement capacity and degree of habitat specialization provides much insight into how genetic diversity is distributed spatially. 2) It is probably unwise to infer dispersal from “proxy” traits such as insect wing morphometrics. Although more difficult to measure, the only way to understand dispersal is to study elements of dispersal itself. 3) At the community level, aquatic habitat heterogeneity and complex landscape topography produce an intricate mosaic of environmental conditions in mountain streams, including some conditions that are expected to be substantially more resilient to global change than others. We will then converge on a general conclusion that habitat heterogeneity and connectivity allowing organism movement among habitat patches is and will continue to be essential for maintaining diversity in stream-dwelling insects through broad-scale environmental shifts associated with climate change. 6 Prof. Monika Springer Universidad de Costa Rica, Costa Rica Monika is a biologist who graduated from the University of Munich, Germany. She arrived in Costa Rica for the first time in 1990 as an exchange student, and since 1995 she has worked at the School of Biology of the University of Costa Rica, where she is a full professor. She is also an associate researcher at the Center for Research in Marine Sciences and Limnology, CIMAR, and curator of Aquatic Entomology in the Museum of Zoology, University of Costa Rica (MZUCR) located in the Center for Research in Biodiversity and Tropical Ecology (CIBET). Her research interests include the taxonomy and biology of aquatic insects, emphasizing caddisfly larvae and their use as biological indicators in monitoring, managing, and conserving freshwater environments. Trichoptera studies: Perspectives from the Central American land bridge The Central American land bridge, which extends from southern Mexico to the northeast of Colombia, is part of the Mesoamerican region and includes the countries of Guatemala, Belize, Honduras, El Salvador, Nicaragua, Costa Rica, and Panama (from north to south). Due to its geological history, position between two oceans, and variable topography, this region hosts many terrestrial and aquatic ecosystems and is considered one of the world's Biodiversity hotspots. As several authors pointed out, Central America is considered a hyper-diverse area within the Neotropical region, harboring 5-12% of the world's species richness. However, when comparing scientific production on biodiversity topics, there are significant differences between the northern countries and their southern neighbors, Costa Rica and Panama, which produce almost five times as many peer-reviewed scientific papers. This pattern also applies to our knowledge of caddisflies, with less information published from El Salvador, Belize, Honduras, and Nicaragua. A literature review was conducted based on the Catalog of the Neotropical Trichoptera, published by Holzenthal and Calor in 2017, and subsequent publications to compile specific information for each country. To date, 15 families and 61 genera have been recorded from the seven Central American countries, with a total of almost 800 species, 545 representing new species. As a result of a former 10-year inventory by Holzenthal and co-workers in Costa Rica, the country accounts for 295 holotypes, while 179 belong to Panama, reflecting the recent and ongoing efforts made by Armitage and collaborators. For the past nine years, this research team has doubled the amount of Trichoptera species for Panama and added 2 families and 11 genera to its inventory, reaching now a total of 533 species from 56 genera. This makes Panama the country with the most caddisfly species within the region, followed closely by Costa Rica, which hosts the highest number of species per area, with nine species per 1000 km2. The remaining five countries show significantly lower numbers, and, together with the fact that 30% of the species were collected so far in only one country, this is most certainly an indicator of the low sampling effort in most Central American countries, as stated also by several other authors. As for the immature stages, knowledge is even less, with only 7% of all Central American species having their larval stage associated and described, despite their well-known importance as biological indicators in rivers and streams. On the other hand, due to their widespread use in biomonitoring programs and environmental impact studies, a vast amount of information is being produced on the abundance and distribution of caddisfly larvae in various water bodies. Collaborative research efforts, capacity building, and the commitment to hosting local, well-maintained collections are necessary to improve our knowledge of the highly threatened Central American freshwater biodiversity, identify conservation gaps, and help achieve more integrative watershed management in this especially vulnerable region. 7 Assessing trichopteran diversity in the Oglán River watershed: Insights from Amazonian Kichwa communities Silvana Gallegos-Sánchez1,2 and Iván Jácome-Negrete1 1–Facultad de Ciencias Biológicas, Universidad Central del Ecuador, Campus El Dorado-Itchimbía, Quito, Ecuador 2–ECOFORENSIC CIC Corresponding author: Silvana Andrea Gallegos Sánchez ([email protected]) The Oglán River flows through a small watershed where several Amazonian Kichwa communities reside in their ancestral territory. Much of this territory comprises pristine tropical rainforests with unpolluted streams and rivers. However, anthropogenic pressures such as oil extraction and logging pose significant threats to this area, where knowledge about Trichopteran diversity is limited. To address this gap, we initiated a citizen science project involving the Pablo López del Oglán Alto and the Elena Andy del Uklan Yaku Communities. Together, we actively sampled five streams and the Oglán River to assess the diversity of aquatic macroinvertebrates. We identified and categorized Trichoptera from other orders and analyzed the community composition. In total, we collected 1333 aquatic invertebrates, of which 15% (197) were caddisfly larvae. We identified 10 Trichopteran families and 17 genera. The most abundant family was Hydropsychidae, followed by Leptoceridae. Among the sampled rivers, the Yurak Oglan stream exhibited the highest diversity (H’=2.25). In Kichwa indigenous knowledge, all trichopteran taxa were referred to as "Rumi Shundu." Hydropsychidae larvae were primarily utilized as fishing bait. Functional traits of the ancestral caddisfly larva Xinyu Ge1 and John C. Morse2 1–Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, College of Life Sciences, Tianjin Normal University, Tianjin, P.R. China 2–Department of Plant and Environmental Sciences, Clemson University, Clemson, South Carolina, USA Corresponding author: John C. Morse ([email protected]) Recent phylogenomic studies have concluded that the ancestor of suborder Integripalpia and order Trichoptera probably had a larva that was “free living,” without a portable case or fixed retreat (Frandsen et al. in press, Ge et al., in review). We reflect further on the phylogenies inferred from those investigations with hypotheses regarding other probable functional traits of larvae of the Trichoptera ancestor and its immediate descendants and of the extant amphiesmenopteran sister lineage Lepidoptera. Like the ancestral moth larva, the ancestral caddisfly larva was not only “free living,” but also was often submerged and with movement enhanced by a hook on each anal proleg. The ancestral integripalpian larva constructed a precocious dome-like pupal shelter (= portable case) in instar V. The hydroptiloid ancestor underwent hypermetamorphosis and constructed a purse-shaped case. Larvae of the glossosomatoid-rhyacophiloid ancestor lived in lotic habitats and spun semipermeable cocoons. Meanwhile, the ancestral annulipalpian larva constructed a fixed retreat with an upstream filternet in lotic habitats on exposed surfaces of stable substrates in fast water. 14 Using submerged light traps to learn about caddisflies that dive to oviposit around the world William Gerth1, Christina Murphy2, Ivan Arismendi1, and Tatiana Latorre-Beltran1 1–Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, Oregon, USA 2–U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, University of Maine, Orono, Maine, USA Oviposition is a critical step in the life cycles of aquatic insects. Adult caddisflies exhibit a variety of oviposition methods. In some species, females dive and swim to oviposit on submerged substrates. In the process of sampling for another purpose, we found that submerged light traps can be an effective way of catching adult female caddisflies as they dive and swim to lay eggs. We have also summarized published information on North American species that dive and swim or have leg modifications that would presumably facilitate swimming and documented the additional species we captured in submerged light traps. In North America, 24 caddisfly species are known to have females that dive and swim to oviposit and 41 species are recorded as having leg modifications that suggest they could swim. Most are in the family Hydropsychidae plus a few in other annulipalpian families, but there are also diving species in the families Hydroptilidae and Phryganeidae, and leg modifications that would suggest swimming ability in the Glossosomatidae. We would like to collaborate with colleagues around the world to deploy submerged light traps to document additional caddisfly species that dive and swim for egg laying. Elevational diversity of Rhyacophila (Trichoptera: Rhyacophilidae) in the Hengduan Shan Sonja Gerwin, Xiling Deng, and Steffen U. Pauls Senckenberg Research Institute and Natural History Museum Frankfurt, Germany Steffen U. Pauls (stef[email protected]) Aquatic insects are particularly sensitive to disturbances in aquatic habitats because their life cycles are directly linked to physico-chemical conditions in these environments. Here we combine molecular tools and ecological analysis to determine general distributional patterns and associated environmental variables for an unknown fauna of Rhyacophila caddisflies in the Hengduan Mountains in China. In total 415 larval and 109 adult specimens from four river catchments between 1022 m - 4381 m a.s.l. were used for the analyses. Tree-based and distance-based methods were used to delimit putative molecular operational taxonomic units (MOTUs) based on both mitochondrial COI (mtCOI) and nuclear wingless (nuWG) data. Overall, 33 adult males and 14 females were successfully associated to larvae. Many MOTUs were geographically restricted and rare, often occurring only in one or two sampling sites. PCA and multivariate GLM analyses confirmed the importance of altitude and chemical stream variables in explaining the abundance of many larval Rhyacophila MOTUs. In combination, the strong explanatory power of altitude and high level of geographical restriction of MOTUs indicates that Rhyacophila in the Hengduan Shan are vulnerable to ongoing climate change. Relationship of Trichoptera species in Iceland with other North-Atlantic islands and the mainland of Europe Gísli Már Gíslason and Snaebjörn Pálsson Institute of Life and Environmental Scineces, University of Icelan, Reykjavík, Iceland Corresponding author: Gísli Már Gíslason ([email protected]) Geographic variation in the COI mtDNA barcode marker in ten of the Trichoptera species from Iceland indicates distinct histories where different species show indication of varying time since colonization of the island and separate evolution restricted to Iceland. One of the three Holarctic species, the parthenogenic 15 Apatania zonella, appears to have originate near the Bearing Strait and dispersed west to Scandinavia and diverged into a separate lineage within Iceland, where another route was east N-America to Greenland and the populations met in Iceland. Limnephilus fenestratus and L. picturatus do not show a clear split between the Nearctic and Palearctic. Four of the palearctic species L. affinis, L. griseus, L. sparsus, L.elegans present unique lineages within Iceland, suggesting an early colonizeration after the Ice-age. Variation within the three other species reflect a recent origin. Potamophylax cingulatus originates in Central Europe and its variation reflects a migration route west to France and then north along the coast to Britain and finally to Iceland in the 20th century. Limnephilus decipiens and Microptsectra sequax, a very recent colonizer (21st century) fall genetically in with other European species. Five of the ten species suggest unique mtDNA lineages within Iceland suggesting an early colonization. The Trichoptera of Ecuador Ralph W. Holzenthal1 and Blanca Ríos-Touma2 1–Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA 2–Grupo de Investigación Biodiversidad, Medio Ambiente y Salud (BIOMAS), Facultad de Ingenierías y Ciencias Aplicadas. Ingeniería Ambiental, Universidad de Las Américas, Quito, Ecuador Corresponding author: Ralph W. Holzenthal ([email protected]) Ecuador, crossed by the equator and bisected by the Andes, harbors a remarkable diversity of plant and animal species. For example, 1663 bird species have been recorded from the country compared to 1023 for all North America. This diversity is reflective of the northern Andean region of South America as a whole, probably the most biodiverse region on the globe. What is the caddisfly diversity of Ecuador? To address this question, we have been continuously exploring the fauna since 2011. To date, we have recorded 493 species from the country based on 49,914 curated and databased specimens from 265 collection events. Of these, 25 new species and one new genus have been described and 172 new or potentially new species await study and description. The current total of species is 183 more than recorded in our first assessment of the fauna published in 2017, representing more intensive field work since 2020. Chao 2 species richness estimator based on species incidence data predicts that the actual fauna contains 689 species. In addition to more survey work, future efforts will include COI barcode sequencing for each species and continued research into speciation processes and ecological adaptations based on genetic data Analyzing adult Trichoptera to assess upstream disturbance: one (caddis) metric to rule them all? David C. Houghton Department of Biology, Hillsdale College, Hillsdale, Michigan, USA Corresponding author: David C. Houghton ([email protected]) Adults of Trichoptera are valuable for assessing riverine biotic integrity; however, it is not clear which specific metric(s) are most effective for doing so. In this study, >600,000 adult caddisflies were sampled from 808 stream sampling sites throughout the northcentral United States. Specimen data were compiled into 24 water quality metrics encompassing taxonomic richness, diversity indices, functional traits, pollution tolerance, and organic biomass. Each metric was tested for its ability to predict the known level of undisturbed habitat upstream of each sampling site using simple linear regression modeling. Twenty models were significant and seven had R2 >0.25. Undisturbed upstream habitat increased with percentage of shredder biomass (0.27), ratio of shredders to filtering collectors (0.28), and richness at the species (0.41), genus (0.53), and family (0.61) levels, and decreased with percentage of filtering collector biomass (0.34) and the Hilsenhoff Biotic Index (0.37). A multiple linear regression analysis of all 24 metrics produced a model that explained only 8% more dataset variation than did family richness exclusively. These results indicate that taxonomic richness metrics constitute the most effective predictors of undisturbed upstream habitat, and that family richness may be the most valuable due to its ease of use and low stochastic variation. 16 Taxonomy and DNA barcodes of the family Philopotamidae (Trichoptera: Insecta) from India Zahid Hussain1, Aquib Majeed1, Tabraq Ali1, Sajad H. Parey1, and Manpreet S. Pandher2 1–Insect Systematics Research Lab, Department of Zoology, School of Biosciences and Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, India 2–High Altitude Regional Centre, Zoological Survey of India, Saproon, Solan, Himachal Pradesh, India Corresponding author: Zahid Hussain ([email protected]) The family Philopotamidae, commonly known as finger-net caddisflies, under the suborder Annulipalpia, is represented by 1508 species under 26 genera all over the Globe and 625 species are inhabitants in the Oriental region. In India, the family is represented by 7 genera and 155 species. These organisms are significant bioindicators of water quality and are crucial in the aquatic food web. Despite their ecological importance, the taxonomy and molecular profiling of Philopotamidae in India remain inadequately explored. This study aims to fill this gap by providing a comprehensive taxonomic revision and DNA barcode assessment of the Philopotamidae family in India. This study provides the first detailed taxonomic revision and DNA barcode analysis of the Philopotamidae family in India, contributing to the global efforts in cataloging biodiversity and understanding evolutionary relationships within Trichoptera. In the present study, we have identified seven species of Philopotamidae with notes on their DNA barcodes. The complete taxonomic overview and phylogenetic analysis of the species shall be presented during XVIIIth Intranational Symposia on Trichoptera at Ecuador. First data on Trichoptera of the Putorana Plateau (Northern Siberia) Vladimir Ivanov1, Stanislav Melnitsky1, and Andrey A. Przhiboro2 1–Department of Entomology, Saint-Petersburg State University, St. Petersburg, Russia 2–Laboratory of Freshwater and Experimental Hydrobiology, Zoological Institute of Russian Academy of Sciences, St. Petersburg, Russia Corresponding author: Vladimir D. Ivanov (v[email protected]) The Putorana Plateau is a mountain massif up to 1.7 km a.s.l. situated at 67–71°N, south of the Taymyr Peninsula in northwestern part of the Central Siberian Highlands. It is formed by basalts from the Siberian Traps. The plateau is cut by deep valleys with rivers and lakes. The Putorana region has a high diversity of biotopes and comprises three landscape zones: taiga, predominantly larch forest in valleys, mostly below 600 m, mountain tundra generally between 600 and 1000 m, and arctic desert usually above 900 m. Over one thousand adult and immature caddisflies were collected by the latter author in 2019–2023 from several hundred localities in nine areas of the Putorana Plateau. More than 25 species were identified; some of them seem to be new for science. Most of the recorded species belong to the suborder Integripalpia with dominant families Apataniidae and Limnephilidae. Other families are Polycentropodidae, Glossosomatidae, Phryganeidae, and Brachycentridae. The fauna is peculiar in the absence of filter-feeding lotic species and the complete absence of the Brevitentoria families. Polycentropodidae, Hydroptilidae and Glossosomatidae are represented by a single species each. Males of the predominantly parthenogenetic species Apatania forsslundi were found for the first time. 17 Morphology outperforms DNA barcoding in identifying Trichoptera in Ecuadorian streams Gabriela Jijón1,2, Isabella M. Errigo1,2,3, Jessica Wicks1, Natalie Nyborg1, Lillian Buck1, Daniel Davis1, Sam Standring1, John Chaston1, Blanca Rios-Touma2, Paul B. Frandsen1 1–Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, USA 2–Grupo de Investigación en Biodiversidad, Medio Ambiente y Salud (BIOMAS), Facultad de Ingenierías y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador 3–Department of Natural Resources, Cornell University, Ithaca, New York, USA Corresponding author: Gabriela Jijón ([email protected]) Using macroinvertebrate bioindicators is increasingly critical given the high levels of disturbance experienced in aquatic environments, particularly in the Neotropics. Such bioassessment studies have primarily characterized macroinvertebrate communities using traditional morpho-taxonomic identification approaches. With the rapid development of sequencing technologies, DNA-based approaches might allow more efficient identification of specimens in stream surveys. However, characterizing some groups with molecular-based approaches may be more challenging than others. For example, the high diversity of Trichoptera and low sequence representation of Neotropical species in the reference barcode databases can prevent accurate classification of their DNA barcodes. We performed a comparative study in Ecuadorian streams to assess the effectiveness of molecular-based approaches against the traditional characterization method of macroinvertebrate communities. Replicate samples were collected in ten sites across an elevation gradient in Ecuador and compared using morpho-taxonomic and metabarcoding approaches. We found low taxonomic overlap at family and genus ranks across sites for the macroinvertebrate communities, potentially due to a lack of reference species in the barcode databases and primer bias. Notably, lower Trichoptera richness was documented in the DNA approach compared to the morphological. Considering this, I will assess the state of Ecuadorian caddisfly barcodes in databases, identify gaps, and recommend improvements. Contribution to the fauna, distribution, and DNA barcoding data of caddisflies (Insecta: Trichoptera) in Croatia Mladen Kučinić Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia Corresponding author: Mladen Kučinić ([email protected]) The Republic of Croatia is geographically located in the central and southern part of Europe, where it belongs to the Central European and Mediterranean countries. It has a surface area of 56,000 km2. Based on the climatological, geological, and geographical characteristics of the Croatian territory, three main regions can be distinguished: the Pannonian-Peripannonian area, the mountainous central area, and the Mediterranean area. Caddisfly studies began in Croatia at the beginning of the 19th century. So far, 215 species of caddisflies have been recorded in the fauna of Croatia, with more than 100 species recorded in all three biogeographical regions. During investigations in the last ten years, several new species of caddisflies have been found or described in the fauna of Croatia, e.g.: Rhyacophila delici Kučinić & Valladolid, Agapetus kampos Oláh, Tinodes antonioi Botosaneanu & Taticchi-Viganò, Hydroptila simulans Mosely, Oxyethira falcata Morton, Ecclisopteryx asterix Malicky, E. ivkae Previšić, Graf & Vitecek, and Stenophylax mitis McLachlan. In addition to several new species, about 180 species of Trichoptera from the Croatian fauna have been DNA barcoded to date, with 600 DNA barcoded specimens submitted to the BOLD database. Faunistic research and DNA barcoding of Croatian caddisflies will continue in the coming years. 18 Higher predicted climate-change vulnerability for spring-dwelling freshwater biota Mathias Kümmerlen1,2 and Steffen U. Pauls3 1–Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany 2–Bundesamt für Naturschutz, Bonn, Germany 3–Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany Corresponding author: Steffen Pauls ([email protected]) Environmental change threatens freshwater biodiversity through altered temperature and precipitation patterns. However, knowledge and data are frequently insufficient to determine impacts at the species level, leading to misinterpreted species vulnerability. Conversely, phylogenetic relationships, current distributions and ecological traits of the caddisfly subfamily Drusinae are well known. Thus, we assessed individual and trait-specific climate change (CC) vulnerability for 47 Drusinae species, by setting up species distribution models (SDMs). Species were grouped by larval feeding guild, stream zonation preference and level of endemism. Models were calibrated with predictors describing climate, topography and geology at a spatial resolution of 1 km² and were projected for five general circulation models under four future climate scenarios. To limit dispersal, distribution projections were restricted to a maximum of 500 km until the year 2080. Relative predicted range change fluctuated between -100% and 197%, with extinction predicted for five species. Altitudinal shifts varied between -2% and +15%, with distribution centroids shifting between 28 km and 119 km. Our results identify stream zonation, a non-phylogenetic trait, as the best indicator of CC vulnerability. Further, two important conclusions are highlighted: monitoring is best done at the species level, while the biodiversity of springs and low order streams requires considerably more research. Trichoptera dispersion: insights from lateral and longitudinal sampling Tatiana Latorre Beltrán1, William Gerth1, Ivan Arismendi1, and Blanca Ríos-Touma2 1–Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvalis, Oregon, USA 2–Grupo de Investigación Biodiversidad, Medio Ambiente y Salud (BIOMAS), Facultad de Ingenierías y Ciencias Aplicadas. Ingeniería Ambiental, Universidad de Las Américas, Quito, Ecuador Corresponding author: Ivonne Tatiana Latorre Beltrán ([email protected]) Adult aquatic insects play a vital role in supporting aquatic and terrestrial food webs, with their dispersion and emergence influencing higher trophic levels in adjacent ecosystems. Given the abundance and diversity of Trichoptera, study of their dispersal patterns contributes to understanding the link between aquatic and adjacent systems. Here, we sampled adult aquatic insects in the HJ Andrews experimental forest in western Oregon, USA, to investigate lateral and longitudinal dispersion patterns. For the 2023 summer, six double rows of sticky traps were distributed within the main channel of the stream and in the riparian zone. Each trap was directed upstream, downstream, left, and right. We repeated this experiment six times in three streams for lateral dispersion and one for longitudinal. Also, five Malaise traps were set in one site. We observed five caddisfly genera dispersing laterally away from streams, with Micrasema exhibiting the greatest dispersion distance. Within the EPT group, Trichoptera comprised 68.5% of the capture in instream traps, showcasing a preference for upstream-downstream movement over lateral movement. Rhyacophila and Dolophiloides were the most abundant, dispersing longitudinally. Our findings contribute insights into the dispersion dynamics of aquatic insects, highlighting the prevalence of Trichoptera and the differential movement patterns observed longitudinally. 19 Species diversity of caddisflies (Insecta: Trichoptera) from lowland forest springs, Surat Thani Province, southern Thailand Pongsak Laudee and Pimpajee Kaewwong Faculty of Innovative Agriculture and Fishery Establishment Project, Prince of Songkla University, Surat Thani Campus, Muang District, Surat Thani Province, Thailand Corresponding author: Pongsak Laudee ([email protected]) Cool springs and their streams of lowland tropical rainforests are unique ecosystems fed by groundwater outflow. The sediment of the cool springs is mainly sand and leaf detritus. Four cool springs in lowland tropical rainforest of Surat Thani Province, southern Thailand were chosen. Larvae and adults of caddisflies were collected with aquatic nets for larvae, and screen and pan light traps for adults. The preliminary result showed that Paduniella sampati, Ecnomus quordaio, Triaenodes themis, and Oecetis biramosa, are the most abundant species in these cool springs. Caddisfly species identification via wing morphometrics Stella Li, Colette Christensen, and Patina K. Mendez Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA Corresponding author: [email protected] Species identification is required for biological and conservation applications but remains challenging in entomology where specimens are small and require expert skills for identification. Geometric morphometrics may be an underexplored method for species identification but has been used in the literature alongside machine learning to identify botanical scans of leaves to species. Using bulk light trap samples from Curry Creek in Northern California, we scanned mounted wings of males and females from the caddisfly families Sericostomatidae and Hydropsychidae, identifying 38 and 45 landmark locations, respectively. Using Generalized Procrustes Analysis (GPA) and Principal Component Analysis (PCA) we determined differences in venation between species and sex. GPA identified the central crossveins in Sericostomatidae as having the most variation throughout all specimens for both fore and hind wings, and PCA highlighted sexual dimorphism, particularly in the central crossveins, where males had more reduced wing venation than females. For Hydropsychidae, tests likewise revealed variation largely in the central crossveins; PCA scores quantified at least 50% variation between wing landmarks, enough to distinguish species into three distinct clusters for the site. DNA barcoding and taxonomic insights of subfamily Hydropsychinae (Hydropsychidae: Trichoptera: Insecta) from India Aquib Majeed1, Tabraq Ali1, Zahid Hussain1, Sajad H. Parey1, and Manpreet S. Pandher2 1–Insect Systematics Research Lab, Department of Zoology, School of Biosciences and Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, India 2–High Altitude Regional Centre, Zoological Survey of India, Saproon, Solan, Himachal Pradesh, India Corresponding author: Sajad H. Parey ([email protected]) The Hydropsychinae subfamily, belonging to the Hydropsychidae family of Trichoptera, represents a significant component of freshwater macroinvertebrate fauna in India. Despite its ecological importance, the taxonomic identification of Hydropsychinae species in India has been largely based on traditional morphological characteristics, which can be challenging due to the high morphological variability within the subfamily. The application of DNA barcoding provides a promising molecular approach to complement traditional taxonomy and enhance species identification accuracy. Our analysis revealed distinct barcode clusters for different 20 Hydropsychinae species, indicating the efficacy of DNA barcoding in discriminating and identifying species within this subfamily in the Indian context. In this study, we conducted a comprehensive morphological and DNA barcoding analysis using the mitochondrial cytochrome c oxidase subunit 1 (COI) gene to investigate the taxonomic relationships and biodiversity of Hydropsychinae species collected from various freshwater habitats across India from 2019-2023. We have generated barcodes of 49 specimens of Hydropsychinae. Additionally, the taxonomic insights gained from the DNA barcoding data facilitated a better understanding of the phylogenetic relationships and evolutionary history of Hydropsychinae species in India. Complete taxonomic description, DNA barcode data and phylogenetic relationship of the family Hydropsychidae in India shall be presented. Growth and development of undergraduate Trichoptera researchers Patina K. Mendez Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA Corresponding author: Patina Mendez ([email protected]) Team Caddis is a group of undergraduate researchers at the University of California, Berkeley who work collaboratively on small-scale, iterative research questions using caddisflies as their primary model organism. Team members include students with a wide range of experience and skills from novice researchers to senior thesis students. The research and learning space centers on interdependent cultural norm framings hypothesized to signal inclusion and belonging for students of historically underrepresented backgrounds and increase persistence in STEM. Over the past 10 years, ~70 undergraduate members of Team Caddis have contributed to museum and ecological studies including: developing methods for imaging fluid-based Trichoptera collections, sorting and identification of monthly light trap samples from an intermittent stream in California, species distribution models of California Caddisfly genera, exploring wing venation for species associations of adult caddisflies using geometric morphometrics, and developing species description and illustration pages for the 300+ species of California caddisflies. Members of Team Caddis participate for ~2.5 semesters, experience an increased sense of belonging in research spaces, learn to collaborate, and develop research skills. “Sense of Presence” (special photographic presentation) Rogier Maaskant Rotterdam, The Netherlands; [email protected] “The tiny creatures that run the world,” is how myrmecologist Edward O. Wilson described insects. They are nature’s cleaners, food for many other species and are essential for the pollination of plants, including our crops. For years, their populations have been plummeting dramatically due to habitat loss and the use of pesticides. It is vital that we stay connected with them and that is why they deserve a stage to put their importance and beauty in the limelight. Rogier Maaskant’s enchanting images unveil a diverse array of insects in flight during twilight and nighttime – in forests and above fields, ditches, and ponds around Rotterdam, Netherlands. By using strobe light, his single exposures provide a unique view of the flight of caddisflies, moths, lacewings, dragonflies, gnats, and various other species that illustrate the rich biodiversity. For Sense of Presence, Maaskant collaborated with scientists and insect experts. His work is in line with the current era of renewed interest in nature and a widespread awareness of the need to protect it. 21 Landuse and elevation-driven changes in caddisfly assemblages in Neotropical streams in Ecuador Andrés Morabowen1, Blanca Rios-Touma1, Isabella M. Errigo1,2,3, and Paul B. Frandsen2 1–Grupo de Investigación en Biodiversidad, Medio Ambiente y Salud (BIOMAS), Facultad de Ingenierías y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador 2–Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, USA 3–Department of Natural Resources, Cornell University, Ithaca, New York, USA Corresponding author: Andrés Morabowen Mantilla ([email protected]) Freshwater ecosystems in Ecuador face ubiquitous threats, and conservation strategies should focus on the connectedness of different altitudinal ecosystems. To assess the uniqueness of freshwater macroinvertebrate communities along an altitudinal gradient, we sampled caddisfly larvae at two different altitudes (1800 and 550 m a.s.l.). We examined the Trichoptera assemblages, abundance, and distribution across 18 streams undergoing various levels of land-use modification at two different altitudes. The two altitudinal gradients, Nanegalito (1800 m a.s.l.) and Mashpi (500 m a.s.l.) are in the Andean Chocó ecoregion, a biodiversity hotspot. We found significant differences associated with changing environmental conditions at the two altitudinal sampling sites driven by specific genera. Our findings highlight the uniqueness of the freshwater Trichoptera communities along the Andean mountain range. Also, assemblages at the two different elevations responded to different environmental stressors. In the upper basins ammonia was the main stressor influencing differences in the Trichoptera community, and in the lower rivers, flow and oxygen saturation were responsible for differences among sites. Thus, we urge the implementation of management practices that support consistent conservation efforts across the entire altitudinal gradient. The connectivity of these habitats is crucial for preserving genetic diversity, thereby increasing ecological resilience and enhancing ecosystem services. Larval taxonomy of the net-spinning caddisfly Cernotina truncona Ross, 1947 (Trichoptera: Polycentropodidae) Alexander Orfinger1, Truc Bui1, Andrew Rasmussen2 1–Department of Life Science, Dalton State College, Dalton, Georgia, USA 2–Center for Water Resources, Florida A&M University, Tallahassee, Florida, USA Corresponding author: Alexander Benjamin Orfinger ([email protected]) The polycentropodid genus Cernotina consists of diminutive caddisflies, with the largest individuals reaching maximum lengths of 8-9 mm. Of the seven Nearctic species, only the larva of C. spicata Ross, 1938 has been described and illustrated to date. Cernotina spicata is one of just three species of the genus recorded from the southeastern United States, the others being Cernotina calcea Ross, 1938 and Cernotina truncona Ross, 1947. Using ecologically and geographically associated larval specimens, we describe and diagnose the larva of C. truncona, noting subtle but consistent differences from C. spicata. Exploring the Trichoptera in the Taxonomic Catalog of the Brazilian Fauna: recent progress and perspectives Fabio B. Quinteiro1, Adolfo R. Calor2, Gleison R. Desidério3, Leandro L. Dumas4, Ana Lucia Henriques-Oliveira5, Rafael Pereira6, Ana Maria Pes7, Allan P.M. Santos8, and Albane Vilarino9 1–Laboratório de Estudos Comparativos em Insetos, Universidade Federal do Pará (UFPA), Instituto de Estudos Costeiros (IECOS), Bragança, Pará, Brazil 2–Laboratório de Entomologia Aquática, Instituto de Biologia, Universidade Federal da Bahia (UFBA), Salvador, Bahia, Brazil 3–Programa de Apoio à Fixação de Jovens Doutores no Brasil (PROFIX-JD), Laboratório de Citotaxonomia e Insetos Aquáticos (LACIA), Instituto 22 Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil 4–Laboratório de Insetos Aquáticos (LABIA), Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil 5–Laboratório de Entomologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Cidade Universitária, Rio de Janeiro, Brazil 6–Laboratório de Entomologia Aquática, Instituto de Biologia, Universidade Federal da Bahia (UFBA), Salvador, Bahia, Brazil 7–Programa de Apoio à Pós-Doutores (PRODOC), Laboratório de Citotaxonomia e Insetos Aquáticos (LACIA), Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil 8–Laboratório de Sistemática de Insetos, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Instituto de Biociências, Rio de Janeiro, Rio de Janeiro, Brazil;, 9–Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil Corresponding author: Fábio B. Quinteiro ([email protected]) The Taxonomic Catalog of the Brazilian Fauna (CTFB) has been active since December 2015, providing comprehensive information on Brazil’s animal fauna. In the 2020 checklist, Trichoptera comprised 728 species, making up 4.9% of the global caddisfly diversity, with Odonata ranking higher at 867 species. Brazil boasts approximately 934 Trichoptera species records (5.4% of the global caddisfly diversity), with 635 being endemic, surpassing Odonata’s count of 910 species. This makes Trichoptera the most diverse aquatic insect order in Brazil. The Atlantic Forest remains the most-species rich biome, with 521 species (377 of them endemic), followed by the Amazon, with 306 species (207 of them endemic). Hydroptilidae remains the most diverse family, with 205 species, of which 23% were described in the last four years. The rise in species count might be attributed to the increasing caddisfly taxonomy research groups (currently at least six major groups) across three Brazilian states, involving the second and third generations of Brazilian caddisfly taxonomists. With an average description rate of 28.8 species/year from 2015–2024, the estimated Brazilian caddisfly diversity of 1,710–1,828 species could be uncovered within 59.4–63.5 years. The next phase involves incorporating distribution data to create online distribution maps. Microcaddisflies (Trichoptera: Hydroptilidae) of the Baja California peninsula, Mexico, and their biogeographic affinities. Mauricio Ramírez-Carmona1, Atilano Contreras-Ramos2, and Robin E. Thomson1 1–Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA 2–Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, México City, Mexico Corresponding author: Mauricio Ramírez-Carmona ([email protected]) Desert habitats dominate the Baja California peninsula, yet they contain remnant aquatic systems (oases) representing isolated islands of biodiversity. Previous faunal surveys have reported the distribution of 11 caddisfly families in the region, but the family Hydroptilidae has not been documented (Dennig, 1964). A single microcaddisfly species has been reported from the southern Baja peninsula (Razo-González, 2023), yet the overall caddisfly fauna of this area remains understudied. This study presents the first microcaddisfly (Hydroptilidae) diversity assessment in the Baja California peninsula. Fieldwork conducted over two years (2021-2022) resulted in the identification of 5 genera: Hydroptila, Leucotrichia, Neotrichia, Ochrotrichia, and Oxyethira. In total, 15 hydroptilid species corresponding to these genera are reported, significantly expanding the known diversity of this group. Also, an area cladogram analysis was performed to evaluate the biogeographic affinities of the Baja California peninsula. These findings contribute to understanding the composition and distribution of Hydroptilidae within this isolated desert landscape, representing an understudied component of the regional aquatic insect fauna. The results provide a crucial baseline for future biodiversity assessments and biogeographic studies in the Baja California peninsula. 23 Microcaddisflies, morphology, and modern molecular methods: collections-based research to establish the microcaddisfly phylogeny Robin Thomson Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA Corresponding author: Robin Thomson ([email protected]) The family Hydroptilidae is an extremely diverse family within Trichoptera that displays a wide array of ecological, morphological, and habitat diversity. In terms of species diversity, Hydroptilidae is the largest family in the order, containing over 2,600 known species found in all faunal regions of the world. However, little is known about microcaddisfly evolutionary history that is supported by current phylogenetic methods. A stable phylogenetic framework based on statistically supported methods is needed to consistently define taxa and provide context for how they relate to each other and are arranged within the family overall. A total-evidence (molecular + morphology) phylogeny of the family Hydroptilidae will be constructed, including the first morphological assessment of homology across the family and the first molecular dataset to cover the entire family using targeted enrichment techniques, to evaluate the monophyly of the traditionally recognized subfamilies within Hydroptilidae and to infer the evolutionary relationships of the included taxa. In addition to the ability to place and describe new biodiversity, a stable classification will make it possible to pursue numerous research directions, such as character evolution within Hydroptilidae, evolutionary trends across Trichoptera, and the opportunity to integrate sequence data with collections-based data. Sublethal effects of two heavy metals on Nectopsyche sp. (Trichoptera: Leptoceridae) in Andean rivers Christian Villamarín1, Agnes Lohs2, Mishell Donoso1, Blanca Ríos-Touma1, Pablo Castillejo1, Melanie Loachamin1, Milton Sosa1 1–Grupo de Investigación Biodiversidad, Medio Ambiente y Salud (BIOMAS), Facultad de Ingenierías y Ciencias Aplicadas, Ingeniería Ambiental, Universidad de Las Américas, Quito, Ecuador 2–Toxicology Master Program, Duisburg Essen University, Germany Corresponding author: Christian Villamarín ([email protected]) In Ecuador, mining activities have expanded due to increased mining concessions and illegal mining and the sublethal effects of heavy metals on local aquatic biota is little known. Our study conducted microcosm experiments, evaluating the sublethal effects on Nectopsyche sp. (Leptoceridae) through behavioral measurements and biomarkers as an effect of different concentrations of Mercury (Hg) and Arsenic (As). The experiment evaluated concentrations of different regulation values for Hg and As and assessed the effect on individuals for seven days under controlled conditions. Laboratory experiments evaluated the mortality and mobility of the individuals and measured biomarkers such as Catalase activity, Glutathione S-Transferase activity, and Ferric Reducing Antioxidant Power. Mortality did not show significant differences. However, mobility showed significant differences at the highest concentrations. Chronic exposure to Hg increased CAT, GST, and FRAP, but only GST exhibited significant differences. For its part, exposure to As caused a decrease in all measured biomarkers, and CAT and FRAP showed significant differences at the highest concentrations. The results suggest that more detailed studies should be carried out using biomarkers to define the actual effects on freshwater biodiversity caused by mining and define MPLs that do not negatively affect populations in the long term. 30 Spatial distribution of Trichoptera larvae in the Cajas Massif lakes Diego Vimos1, Pablo V. Mosquera2,3, Henrietta Hampel1, and Raúl F. Vazquez4 1–Laboratorio de Ecología Acuática, Facultad de Ciencias Químicas, Universidad de Cuenca, Cuenca, Ecuador 2–Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain 3–Subgerencia de Gestión Ambiental de la Empresa Pública Municipal de Telecomunicaciones, Agua Potable, Alcantarillado y Saneamiento (ETAPA EP), Cuenca, Ecuador 4–Departamento de Ingeniería Civil, Facultad de Ingeniería, Universidad de Cuenca, Cuenca, Ecuador Corresponding author: Diego Vimos ([email protected]) A significant amount of studies on the diversity and ecology of Trichoptera communities has been performed in streams and rivers; nevertheless, very little is known on Trichoptera communities in tropical high mountain lentic water bodies. Therefore, this research aimed at assessing the main variables that restrict the spatial distribution of Trichoptera communities present in the littoral areas of lakes in the Cajas Massif, southern Ecuador. Twenty-four environmental variables (hydro-morphological, water quality and microhabitat) were monitored and macroinvertebrate samples were collected using a hand net in 202 study lakes. The order Trichoptera was present in 65.5% of the lakes and represented 1.6% of the total abundance of the benthic community. Oxyethira was the most representative genus, followed by Metrichia and Anomalocosmoecus. The application of the Partial Canonical Correspondence Analysis and the Generalized Additive Model revealed that altitude was the most influential hydro-morphological variable in the distribution of the Oxyethira, Anomalocosmoecus, Metrichia and Nectopsyche. Influential water quality variables were ammonium (Oxyethira, Helicopsyche, Metrichia and Anomalocosmoecus) and dissolved oxygen (Metrichia and Anomalocosmoecus). Furthermore, microhabitat scale variables did not have any influence on the Trichoptera communities. Therefore, given the ecological role that these insects play and their sensitivity to changes in their habitat, the distribution and diversity patterns observed in this research are likely to contribute to a better ecological knowledge of these very important tropical high mountain water bodies, which could finally contribute to a better conservation of these important aquatic ecosystems of the Ecuadorian Andes. Estimate of the life history and the net spinning habit on Macrostemum radiatum (McLachlan 1872) in the central Honshu Island of Japan Shozo Watanabe 6-5, 4chome, Karatodai, Kitaku, Kobe, Hyogo Prefecture, Japan Corresponding author: Shozo Watanabe ([email protected]) The life history and the habit of the net-spinning caddisfly, Macrostemum radiatum (McLachlan 1872), was studied in a midstream of the Kakogawa River, central Honshu Island of Japan, 2019-2022. This population seems to be bivoltine, or it may be trivoltine through five larval instars with an adult period from spring to autumn. The density and abundance of this species varied seasonally from 64 to 368 individuals/m2, from 0.65 to 18.4 g/m2, respectively, both of which were minimal in summer. However, those were not significantly different between the center and the river's shore. The body in wet weight of the larvae increased proportionally with the logarithm of body size of the larvae: ww=4.34 hw 3.69 (herein ww: wet weight, hw: head capsule width). Those of the final instar larvae decreased from spring to summer and subsequently increased from autumn to winter. The larvae examined in the laboratory constructed their retreat using silk with or without sand grains and also constructed capture nets using silk under stirring conditions. 31    