TBG-Project Steffen Pauls and team

Comparative Genomics

Evolution of silk biosynthesis and associated behavior in caddisflies

Foto: Wolfgang Graf

Institution: Senckenberg Gesellschaft für Naturforschung


The properties of caddisfly silk (polymerizes in aquatic environments, high tensile strength and extensibility) make it an interesting material for potential application, e.g. in surgery. Caddisfly larvae use silk in many different ways, e.g. as underwater life lines, to build filtering nets or living retreats, and even to “glue together” mineral or organic particles to build portable cases. This diverse net- and case-making behavior allows them to exploit a range of ecological niches. In our TBG project we aim to study the genomic basis of different uses and characteristics of caddisfly silk and how these evolved. We aim to accomplish this by (1) sequencing genomes of all caddisfly groups with deviating silk use behavior to obtain a deep caddisfly phylogeny and (2) comparing the sections of the genome that are responsible for silk production among closely related species of caddisflies that use silk in different ways, e.g. those that build cases made purely of silk with those that build cases with mineral particles.

Functional diversification of silk characteristics

Genome size variation may be linked to the functional diversification of silk characteristics and use in caddisflies. Shown are genome sizes (kmer-based/flow cytometry estimates) ordered by phylogenetic lineage (tree and color) and functional use (images above). Genome size varies 12.6-fold across the order, with suborder-specific trends from 170MB in net-spinning (Annulipalpia) to 2130MB in case-building (Integripalpia) species. Illustrations from Thomas et al. 2020. © 2020 The Royal Entomological Society, Systematic Entomology, 45, 670–686.

TBG group members

  • Prof. Dr. Steffen Pauls (SGN)
  • Jacqueline Heckenhauer, Ph.D. (SGN)
  • Dr. Julio Schneider (SGN)
  • external: Prof. Paul Frandsen (Brigham Young University)

Group expertise / Methods

  • whole genome de novo assembly and annotation
  • population genetics
  • phylogenetics
  • anchored hybrid enrichment

Genomes Sequenced

Caddisflies (Trichoptera)


J Heckenhauer, Frandsen PB, Gupta DK, Paule J, Prost S, Schell T, Schneider JV, Stewart RJ, Pauls SU. Annotated Draf Genomes of Two caddisfly species Plectrocnemia conspersa CURTIS and Hydropsyche tenuis NAVAS (Insecta:Trichoptera). Genome Biology and Evolution 11 (12), 3445-3451. https://doi.org/10.1093/gbe/evz264

L Olsen, Heckenhauer J, Sproul J, Dikow RB, Gonzalez V, Kweskin M,Taylor A, Wilson S, Zhou X, Holzenthal R, Pauls SU, Frandsen PB. De Novo Whole Genome Assemblies of Two Case Making Caddisflies Agrypnia staminea HAGEN, and Hesperophlax magnus BANKS. In preparation for Genome Biology and Evolution.

J Heckenhauer, …, Frandsen PB, Pauls SU. Genome size evolution in caddisflies (Insecta: Trichoptera). In preparation for Genome Biology.