Macrostemum

Adults distinguished by strongly marked dark and clear wing membrane patterns; larvae identified by prosternal plate morphology and stridulatory ridge patterns (variable among species). Macrostemum brasiliense exhibits characteristic wing and body patterns with documented melanic female variation. Larvae of M. floridum average 25 mm in length with head width of 2.3 mm in final instar.

Flowing water habitats including streams and rivers; larvae require high current velocity environments. M. alienum collected below dam spillways with high water current during rainy season; M. brasiliense primarily in Atlantic Rainforest streams of southeastern Brazil; M. floridum in tropical streams of southern Thailand.

Cosmopolitan: Neotropical region (15+ valid species, Brazil), Afrotropical region (West Africa, Nigeria, Sudan, Ghana, Ivory Coast, Madagascar eastern slope), Oriental region (Thailand, Japan), Nearctic region.

Larvae are collecting filterers; gut content analysis of M. floridum showed main food items as diatoms, green algae, and blue-green algae.

Larvae undergo five instars; head capsule width measurements provided for all instars in M. floridum. Metamorphotype method used to associate immature stages with adults.

Larvae construct fixed retreats with silken capture nets. M. carolina exhibits retreat polymorphism with three distinct retreat morphs (silken tube entrance, ≈180° silken backstop, flush entrance) representing alternative behavioral phenotypes within a single panmictic population rather than genetic differentiation. M. brasiliense exhibits described courtship behavior and copulation.

Filter-feeding larvae process fine particulate organic matter in lotic ecosystems.

• Trichoptera
• Hydropsychidae
• net-spinning caddisfly
• filter feeder
• lotic
• cosmopolitan
• retreat polymorphism
• Neotropical
• Afrotropical
• Oriental

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Un nouveau Macrostemum Kolenati, 1859, d’Afrique occidentale (Trichoptera, Hydropsychidae)
• Notes sur quelques Macrostemum Kolenati, 1859, du versant oriental malgache (Trichoptera, Hydropsychidae)
• First record of Macrostemum alienum Ulmer 1907 (Trichoptera: Hydropsychidae: Macronematinae) from Ile-Ife, Southwestern Nigeria, West Africa
• Distribution and Occurrence of Four Caddisfly Species in Genus Macrostemum along Nan River in Nan Province, Thailand
• Description of female genitalia, additional morphological variations, and courtship behavior and copulation of Macrostemum brasiliense (Fischer 1970) (Trichoptera: Hydropsychidae)
• The genus Macrostemum Kolenati 1859 (Trichoptera: Hydropsychidae) in the Neotropical Region: Description of two new species, taxonomic notes, distributional records and key to males
• Description of the larva of Macrostemum floridum (Navás 1929) (Trichoptera: Hydropsychidae) and its feeding habits in Kaengkrung National Park, southern Thailand.
• Molecular genetic markers provide no evidence for reproductive isolation among retreat building phenotypes of the net‐spinning caddisfly Macrostemumcarolina
• Downstream Distribution and Annual Changes in Densities of Net-Spinning Trichoptera (Hydropsychidae and Stenopsychidae) in the Yoshino River, Shikoku, Japan, with Special Reference to the Colonization of Macrostemum radiatum McLachlan (Trichoptera: Hydropsycheidae).