Embiidina

Labandeira, 1994

webspinners, footspinners

Family Guides

is a small order of cryptic, soft-bodied insects known as or footspinners, characterized by their unique ability to produce silk from specialized glands located in their swollen foretarsi. They construct extensive silk galleries or tunnels under bark, in leaf litter, or within soil crevices, which serve as protective shelters and foraging sites. The order exhibits pronounced : females are wingless and neotenic, remaining in galleries throughout their lives, while males of most develop wings and disperse to locate mates. Webspinners are primarily tropical in distribution and display facultatively communal with maternal care of and young.

2018 07 04 Haploembia solieri w by Slimguy. Used under a CC BY 4.0 license.

2018 07 03 Haploembia solieri w by Slimguy. Used under a CC BY 4.0 license.

2018 07 02 Haploembia solieri w by Slimguy. Used under a CC BY 4.0 license.

Pronunciation

How to pronounce Embiidina: //ˌɛmbiˈɪdɪnə//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

males are small (often under 10 mm), soft-bodied insects with two pairs of membranous wings that can be mistaken for winged or small stoneflies; however, their wings fold forward over the body rather than backward, and they possess characteristically swollen foretarsi ('Popeye arms') containing silk glands. Females are , nymph-like in appearance, and difficult to distinguish from stages. The enlarged, gland-packed foretarsi are the definitive diagnostic feature separating from all other insect orders. Both sexes have simple chewing mouthparts and .

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Habitat

Tropical and subtropical environments lacking prolonged cold seasons; specifically found in concealed microhabitats including under loose bark, within leaf litter, in soil crevices, under stones, and in rock walls. Suitable exist throughout tropical regions but may be unoccupied; notably absent from some Caribbean drainage forests in Panama and Rica despite apparent habitat suitability. Montane habitats in Central America and Mexico show particularly rich representation.

Distribution

Primarily pantropical with extensions into warm temperate regions; documented from North, Central, and South America, Africa, Asia, and Australia. In North America, native occur in the southern United States with one species reaching southern Oregon; several introduced species (including Oligotoma nigra from the Old World tropics) have established in the southwestern U.S. and California. The order's natural spread is limited by the short distance of flightless females, resulting in relatively depauperate faunas on geologically young land surfaces.

Diet

Feeds on decaying vegetable matter including outer bark, dead leaves, lichens, mosses, and . Some graze specifically on lichens and dried mosses. males do not feed.

Life Cycle

Hemimetabolous development with simple : , nymph, and stages. Nymphs resemble adults in and occupy the same silk galleries. Females remain neotenic (nymph-like) throughout life. In at least some , do not overlap within colonies. Nymphs with maternal care develop significantly faster than those without.

Behavior

Silk production from foretarsal glands used to construct, extend, and repair protective galleries; silk fibers are among the finest known in nature (35-40 nanometers in some ). Exhibits rapid backward movement within galleries as primary escape response from . activity pattern: nymphs and non-reproductive females feed and spin only at night, while -guarding females remain active around the clock. Displays facultatively communal with multiple individuals inhabiting interconnected gallery systems. Females exhibit elaborate maternal care including egg guarding, construction of protective egg coverings from substrate materials and silk, and physical defense against egg . Maternal females increase silk production exponentially after nymph hatch to expand gallery coverage.

Ecological Role

Decomposers contributing to breakdown of plant material in tropical and subtropical ; their grazing on bark, lichens, and detritus facilitates nutrient cycling. Silk galleries may alter microhabitat conditions for other . Serve as for including Sclerogibbidae.

Human Relevance

Generally harmless to humans and not considered pests; occasionally encountered in homes when winged males are attracted to lights at night, sometimes causing concern due to resemblance to . Some introduced have become established in urban environments (e.g., Oligotoma nigra in California). Silk properties have attracted biomimetic research interest for potential applications in biodegradable coatings, nano-fiber textiles, and moisture-responsive materials.

Similar Taxa

Isoptera (termites)Winged male are frequently mistaken for due to similar size, soft bodies, and winged form; distinguished by webspinners' forward-folding wings, swollen foretarsi with silk glands, and different wing venation patterns.
Plecoptera (stoneflies)Small stoneflies may resemble webspinner males in general appearance; separated by stoneflies' lack of silk-producing foretarsi, different wing posture at rest, and aquatic nymphal .
Psocodea (barklice/booklice)Some barklice spin silk and may be confused with in domestic settings; distinguished by different silk production anatomy (not from foretarsi), different body form, and lack of the characteristic 'Popeye' forelegs.