Oligotoma nigra

Black Webspinner

Family: Oligotomidae · Class: Insecta · Order: Embioptera

Oligotoma nigra is a small webspinner in the order Embioptera, family Oligotomidae. Adult females are typically wingless and measure 4 to 6 millimeters (0.16 to 0.24 inches) in length, with elongated, cylindrical bodies that are dark brown to black in coloration. Males are smaller and may possess wings, though specific morphological details for this species remain poorly documented. Like other webspinners, O. nigra possesses enlarged front tarsi containing silk glands, which are used to construct protective silk galleries. The current distribution of Oligotoma nigra in California is not well documented in available scientific literature. The species appears in U.S. Fish and Wildlife Service taxonomic databases, but specific range information and county-level occurrence data have not been comprehensively recorded. Webspinners in general are cryptic insects that may be underreported due to their secretive nature and small size. Habitat requirements for O. nigra have not been specifically studied or documented. Most webspinners typically inhabit areas with loose bark, leaf litter, rock crevices, or soil where they can construct their characteristic silk galleries. These microhabitats provide protection from predators and environmental extremes while allowing access to food sources. The species likely occurs in various terrestrial environments including woodlands, chaparral, and possibly urban areas, though specific vegetation associations remain unknown. Webspinners are generally detritivores, feeding on dead plant material, lichens, and organic debris within their silk galleries. Females remain within their galleries throughout their lives, tending eggs and young nymphs. Males typically emerge from galleries to seek mates, after which they die. Reproduction likely follows the typical embiopteran pattern of incomplete metamorphosis, with eggs developing into nymphs that resemble miniature adults. Seasonal activity patterns and specific life cycle timing for O. nigra have not been documented. Oligotoma nigra does not appear on federal or California state threatened and endangered species lists as of December 2025. NatureServe lists the global conservation status as GNR (Global Not Ranked), indicating insufficient information to assign a conservation rank. The species' conservation needs cannot be adequately assessed due to limited knowledge of its distribution, population status, and ecological requirements. Like many small, cryptic arthropods, O. nigra may face threats from habitat loss and fragmentation, particularly in developed areas of California, but specific threats have not been identified or studied. Scientific documentation for this species remains extremely limited. The information presented here is based on general webspinner biology and taxonomic databases. Detailed ecological studies, distribution surveys, and life history research are needed to better understand this species' status and conservation needs in California. We welcome contributions of verified scientific data, photographs, or field observations to enhance this species account.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.