Sisyridae

Adults distinguished from similar brown lacewings (Hemerobiidae) by wing venation: few cross veins, mostly unforked, with Sc and R1 fused near wingtip. Larvae immediately identifiable by seven pairs of jointed abdominal tracheal gills—no other extant insect family possesses this trait. First instar larvae lack these gills and are free-floating, resembling osmylid larvae but with different habitat use.

Freshwater aquatic-terrestrial ecotone. Adults associated with riparian vegetation overhanging lakes, ponds, and slow-moving rivers. Larvae develop in water on living freshwater sponges and bryozoans. Terrestrial stages (prepupa, pupa) restricted to moist microhabitats near water edge such as under rocks or bark. Bank structure is a decisive factor for local occurrence.

Worldwide distribution across six continents. North America: two genera (Climacia, Sisyra), six species in Canada, Mexico, and United States. South America: Amazon Basin with eight known species; Brazil with 17 species including first records from Caatinga and Espírito Santo. Africa: Western Palaearctic and Afrotropical regions including South Africa, Zimbabwe, Democratic Republic of the Congo, Nigeria, Senegal, Cameroon, Guinea, Zambia, Ivory Coast. Europe: multiple species including Austria, with parasitism records. Australia: Tasmania and mainland with described species including Sisyra pedderensis. Asia: Myanmar (Burmese amber fossils), Russia (Taimyr amber), Israel, Saudi Arabia. Fossil record extends to Late Cretaceous (Cenomanian) with subfamily Paradoxosisyrinae.

Activity patterns vary by climate. In temperate regions, larvae overwinter in cocoons and pupate the following spring. Development duration from larva to pupation ranges from several weeks to one year depending on water temperature and host condition. Adults are crepuscular or nocturnal.

Adults are omnivorous: primarily scavengers on dead arthropods, also consume pollen and honeydew, and occasionally hunt small live invertebrates including aphids. Larvae are obligate predators of freshwater sponges (genus Spongilla and relatives) and freshwater bryozoans (Phylactolaemata), piercing host tissues and sucking out cell contents.

• Spongillidae (freshwater sponges) - obligate larval hostPrimary larval food source; larvae pierce sponge tissues to feed on cell contents. No strict host specificity observed.
• Phylactolaemata (freshwater bryozoans) - obligate larval hostSecondary larval host; used alongside sponges.
• Gyrinophagus aper (Pteromalidae) - parasitoidParasitizes prepupal and pupal stages of Sisyra fuscata; recorded in Austria.
• Trichomalopsis sisyrae (Pteromalidae) - parasitoidParasitoid of Sisyra in Tasmania, Australia.

Eggs laid on overhanging vegetation with protective silk covering. First instar larvae drop into water and are free-floating, serving as dispersal stage. Second and third instars are benthic, developing on living sponges and bryozoans; duration depends on water temperature and host condition. Larvae exit water to pupate in terrestrial cocoon near water's edge. In temperate climates, larvae overwinter in cocoons and pupate the following spring; voltinism varies by region.

Adults are crepuscular or nocturnal. First instar larvae are free-floating and serve as the primary dispersal stage, allowing colonization of new water bodies. Larvae use stouter-than-appearing antennae to aid locomotion on host substrates. Where sympatric, congeneric species may show slight temporal niche separation but can overlap spatially.

Larvae function as specialist predators of freshwater sponges and bryozoans, potentially regulating host populations. Serve as hosts for parasitoid wasps (Pteromalidae), linking aquatic and terrestrial food webs. Adults contribute to nutrient cycling as scavengers and may incidentally pollinate while feeding on pollen.

None documented. Not pests; no economic importance. Occasionally studied as indicators of healthy freshwater ecosystems due to dependence on living sponges and bryozoans.

• Hemerobiidae (brown lacewings)Adults resemble brown lacewings in general appearance and coloration; distinguished by wing venation details (fewer cross veins, Sc and R1 fused near wingtip) and aquatic larval biology.
• Osmylidae (osmylids)Larvae superficially similar to first instar spongillaflies in having long antennae and threadlike mouthparts; distinguished by absence of seven pairs of jointed abdominal tracheal gills in second-third instars, and different habitat (osmylid larvae typically in moist terrestrial habitats or different aquatic niches, not specialized sponge predators).

• aquatic insects
• Neuroptera
• spongivory
• specialist predators
• freshwater ecology
• crepuscular
• fossil insects
• Cretaceous survivors
• tracheal gills
• unique morphology
• host-specific larvae
• parasitoid hosts

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• An overview of the African spongillaflies (Neuroptera: Sisyridae)
• Neuroptera of the Amazon Basin. Part 1. Sisyridae
• Eidonomy and Ecology of two European Spongillafly Species (Neuroptera: Sisyridae)
• Spongillaflies (Neuroptera: Sisyridae) of North America with a key to the larvae and adults
• The spongillafly genus Sisyra Burmeister, 1839 (Neuroptera: Sisyridae) from Brazil: Distributional, taxonomical and bionomical notes
• Foraging Behavior and Food of Adult Spongila-Flies (Neuroptera: Sisyridae)
• A new distribution record for the spongilla fly, Sisyra fuscata (Neuroptera, Sisyridae)
• A new genus of paradoxosisyrine lacewings from mid-Cretaceous Hkamti amber (Neuroptera: Sisyridae)
• Biology, ecology and voltinism of the Australian spongillafly Sisyra pedderensis Smithers (Neuroptera: Sisyridae)
• Taxonomic and distributional notes on Spongilla-flies (Neuroptera: Sisyridae) from Southeastern Brazil with first interactive key to the species of the country
• Trichomalopsis sisyrae Askew, sp. Nov. (Hymenoptera: pteromalldae), a parasitoid of Sisyra (Neuroptera: sisyridae) in Tasmania, Australia
• Studies on Southern Sisyridae (Spongilla-flies) with a Key to the Third-Instar Larvae and Additional Sponge-Host Records
• An Achiasmatic Mechanism That Ensures the Regular Segregation of Sex Chromosomes in Male Meiosis in the Black Spongilla-fly Sisyra nigra (Retzius 1738), Sisyridae, Differs from the Mechanism Commonly Observed Within Neuroptera.