2134/37870
Richard Mason
Richard
Mason
Stephen Rice
Stephen
Rice
Paul Wood
Paul
Wood
Matthew F. Johnson
Matthew F.
Johnson
The zoogeomorphology of case-building caddisfly: quantifying sediment use
Loughborough University
2019
Biogeomorphology
Zoogeomorphology
Macroinvertebrate
Fine sediment
Trichoptera,
Bed armouring
Ecology
Earth Sciences not elsewhere classified
Geology
2019-06-04 09:57:15
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/The_zoogeomorphology_of_case-building_caddisfly_quantifying_sediment_use/9481910
Caddisfly (Trichoptera) larvae are an abundant and widespread aquatic insect group
characterised by the construction of silk structures, including nets and cases. Case building caddisfly have the potential to modify the sorting and mobility of sand and
fine gravel via; 1) case construction, resulting in altered sediment properties; 2)
transporting sediment incorporated into cases over the river bed and; 3) changing
the structure of river-beds via burrowing. To investigate these mechanisms, it is
necessary to understand the mass, size distribution and spatial variability of
sediment use by case-building caddisfly larvae.
We quantified the mineral sediment used by individuals and communities of case building caddisfly in 27 samples, from three sites on a gravel-bed stream. The mass
and size distribution of sediment in individual cases varied between taxa (mass =
0.001 – 0.83 g, D50 = 0.17 – 4 mm). The mean mass of sediment used by the
caddisfly community was 38 g m-2 and varied locally. Sediment use was
predominantly coarse sand (D50 = 1 mm). 64% of sediment use was attributable to
Agapetus fuscipes (Glossosomatidae).
Due to within-species variability in case mass, the abundance of most taxa, including
A. fuscipes, was only weakly associated with the mass of sediment used at the river
scale. Whilst the caddisfly community used a small percentage of the total sediment
available (average 2.99% of the 1 - 1.4 mm size fraction), A. fuscipes used more fine
sediment in their cases at sites where it was more available. Despite variability in
local habitat, all sites supported diverse case-building caddisfly communities utilising
mineral sediment. Consequently, geomorphological effects of case-building caddisfly
are potentially widespread. The results provide novel insights into the specific grain
sizes and quantities of fine sediment particles (g m-2) used by caddisfly larvae, which
represents an important step towards understanding their zoogeomorphic activities.