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Published on: August 3, 2016
Local modification of benthic flow environments by suspension-feeding stream insects
J R Thomson1, B D Clark, J T Fingerut
1Patrick Center for Environmental Research, Academy of Natural Sciences of Philadelphia, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103, USA.
Oecologia
|June 5, 2004
Summary
Larval black flies significantly alter water flow, reducing velocity and increasing turbulence for downstream neighbors. Their feeding appendages, or labral fans, are the primary drivers of these flow modifications.
Area of Science:
- Ecology
- Fluid Dynamics
- Entomology
Background:
- Larval black flies often aggregate, potentially impacting resource availability for downstream individuals.
- Individuals may modify local flow, affecting food particle supply to neighbors.
Purpose of the Study:
- Quantify flow modifications by feeding Simulium vittatum larvae.
- Determine the spatial extent of these flow alterations.
- Relate flow variations to larval feeding appendage movements.
Main Methods:
- Utilized hot-film anemometry in a laboratory flume.
- Measured mean velocity and turbulence intensity downstream from larvae.
- Analyzed velocity time series and power spectra.
Main Results:
- Mean velocity reduced by 75% at 1 mm downstream, with effects extending 60 mm.
- Turbulence intensity increased in the vicinity of larvae.
- Labral fan activity was directly correlated with flow modification and velocity fluctuations.
Conclusions:
- Larval feeding appendages (labral fans) are the main cause of significant local flow modification.
- These flow alterations can impact feeding, growth, and spacing patterns within larval aggregations.
- Understanding flow modification is crucial for black fly ecology and population dynamics.
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