Oral Presentation Society for Freshwater Science 2026 Annual Meeting

Caddisflies of Florida: advancing larval taxonomy by leveraging a species-level inventory based on faunal survey of adults (134972)

Andrew Rasmussen 1 , Alexander Orfinger 2 , Dana Denson 3 , Steven Harris 4
  1. Center for Water Resources, Florida A&M University, Tallahassee, Florida, United States
  2. Department of Life Science, Dalton State College, Dalton, Georgia, United States
  3. Retired, Macon, Georgia, United States
  4. Retired, Knox, Pennsylvania, United States

A benthologist’s focus on the larval life-stage of aquatic macroinvertebrates can lead to an, “I don’t do adults” mentality. This is especially true in regards to primary aquatic insect orders such as Trichoptera in which genus and species descriptions are originally based on adult features (e.g., wing venation and adult genitalia) that are completely different compared to morphological features of the larvae. The outcome of larvae-only studies can be uncertain and low-resolution (family/genus level) taxonomic identifications in groups such as Trichoptera where larval taxonomy is poorly known. To address this issue, species-level knowledge of Trichoptera based on adults can be leveraged to facilitate larval-adult associations through traditional approaches such as larval/adult rearings, the metamorphotype method, and newer approaches using DNA barcoding. Additionally, we believe that comprehensive faunal surveys of Trichoptera adults by deploying collecting equipment (e.g., light traps, emergence and Malaise traps) within a prescribed area is a feasible way to develop species-level inventories that can be used to strengthen aquatic bioassessments and ecological studies. This approach is scalable, and by combining species distributional data of smaller-scale surveys, identification keys can be tailored to larger areas such as states or provinces. In Florida, we have now documented county-level distributions of 220 Trichoptera species representing 46 genera and 19 families within the state (Rasmussen et al. 2025). We are currently using these data as a foundation for developing a new identification guide to the caddisfly larvae of Florida that will include keys to families, genera, and species when possible, species distributional maps, and species notes on biology and ecology. As part of this process, the guide is being illustrated with many new line drawings and specimen photographs.

  1. Rasmussen, A. K., Denson, D. R., Orfinger, A. B., & Harris, S. C. (2025).  Diversity and distribution of the Trichoptera of Florida, United States, with descriptions of five new species. ZooKeys, 1263: 389-439.