Aquatic Insect Bioconstructions Modify Fine-Sediment Entrainment and Mobility

Mason, R. J.; Rice, S. P.; Johnson, M. F.; Wood, P. J.; Vettori, D.

Abstract

The importance of two-way interactions between animals and the physical hydraulic and sedimentological environment are increasingly recognized (e.g., zoogeomorphology). Caddisflies (Trichoptera) are a group of aquatic insects known for their bioconstructions, particularly cases built from fine sediment and silk. Caddisfly cases differ in size, shape and density from the incorporated sediment, and case construction may therefore affect the mobility of these sediments in rivers. However, although communities of caddisfly often use substantial quantities of sediment in case construction, the effect of these bioconstructions on sediment transport in rivers is unknown. We use a flume experiment to compare the bed shear stress required to transport (a) empty caddisfly cases and (b) individual sediment particles, following disaggregation from the case. The cases of three species were considered; two that construct different styles of tubular case (Potamophlax latipennis and Sericostoma personatum) and one that builds a domed case (Agapetus fuscipes). P. latipennis and S. personatum cases were easier to entrain than the sediment grains incorporated into them, whilst A. fuscipes cases were not. Despite their low mass, A. fuscipes cases required the most shear stress to transport them because their domed shape impeded rolling. These findings are important to understand how differences in case design between species, reflect different adaptation strategies to the turbulent hydraulic river habitat. Furthermore, the results suggest that un-attached tubular caddisfly cases may be preferentially transported over other particles on the river bed and thus, where caddisfly occur in high abundance, they may increase fluvial entrainment of sand.

Citation

Mason, R. J., Rice, S. P., Johnson, M. F., Wood, P. J., & Vettori, D. (2022). Aquatic Insect Bioconstructions Modify Fine-Sediment Entrainment and Mobility. Journal of Geophysical Research: Earth Surface, 127(2), Article e2021JF006399. https://doi.org/10.1029/2021jf006399

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2021
• Online Publication Date: Jan 31, 2022
• Publication Date: Feb 1, 2022
• Deposit Date: Feb 7, 2022
• Publicly Available Date: Feb 10, 2022
• Journal: Journal of Geophysical Research: Earth Surface
• Print ISSN: 2169-9011
• Electronic ISSN: 2169-9011
• Publisher: American Geophysical Union (AGU)
• Peer Reviewed: Peer Reviewed
• Volume: 127
• Issue: 2
• Article Number: e2021JF006399
• DOI: https://doi.org/10.1029/2021jf006399
• Keywords: Earth-Surface Processes; Geophysics
• Public URL: https://nottingham-repository.worktribe.com/output/7395696
• Publisher URL: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JF006399
• Additional Information: An edited version of this paper was published by AGU. Copyright 2022 American Geophysical Unio