Macrostemum carolina

(Banks, 1909)

Macrostemum carolina is a net-spinning caddisfly in the Hydropsychidae. Larvae construct silken catchnets within protective retreats to filter food from flowing water. Multiple retreat-building phenotypes exist within this , including retreats with water entrance holes at the end of silken tubes, with 180° silken backstops, or flush with the retreat top. Molecular genetic analysis confirms these phenotypes represent a single panmictic rather than cryptic species.

Macrostemum carolina by (c) Annika Lindqvist, some rights reserved (CC BY), uploaded by Annika Lindqvist. Used under a CC-BY license.

Macrostemum zebratum 204969295 by Lior Carlson. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Macrostemum carolina: /ˌmæk.roʊˈstiː.məm ˌkæ.rəˈlaɪ.nə/

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Identification

Larvae construct silken catchnets and retreats in flowing water; possess typical hydropsychid features including hairy wings and reduced mouthparts. Retreat (three distinct morphs) is not diagnostic of separate or within this .

Images

Habitat

Streams and rivers with flowing water where larvae can construct filter-feeding nets and retreats. Larval stage is fully aquatic.

Distribution

North America; specifically documented from the Savannah River system.

Diet

Larvae are filter-feeders, capturing suspended organic matter and small particles in silken nets.

Life Cycle

Holometabolous with aquatic larval stage, pupal stage in retreat or chamber, and terrestrial stage. Specific timing of and voltinism not documented.

Behavior

Larvae exhibit polymorphic retreat-building , constructing one of three retreat types: silken tube with terminal entrance, 180° silken backstop, or flush-topped retreat. All three morphs co-occur and interbreed freely. Net-spinning behavior used for passive filter-feeding.

Ecological Role

Filter-feeder in stream ; contributes to nutrient cycling and serves as prey for aquatic . Part of the macroinvertebrate used as bioindicators of water quality.

Similar Taxa

Other HydropsychidaeShare net-spinning larval ; distinguished by specific retreat architecture and genetic identity where tested.
Other Macrostemum speciesCongeneric may overlap in distribution; require morphological examination of or molecular markers for definitive identification.

More Details

Retreat Polymorphism

The three retreat phenotypes in M. carolina were initially suspected to represent cryptic or genetically isolated . at three loci (Gpi, Mpi, Pgm) and mitochondrial haplotype analysis found no significant genetic differentiation among morphs, confirming they represent behavioral plasticity or Mendelian within a single interbreeding population.