Araneae

spiders

Suborder Guides

Araneomorphae(Typical Spiders)
Mygalomorphae(Mygalomorphs)

Araneae is an order of air-breathing arachnids comprising over 51,000 described across 136 , ranking seventh in total among all organismal orders. Members are characterized by two body regions ( and unsegmented ), eight legs, cheliceral fangs with venom glands, and abdominal that produce silk. The order is divided into two suborders: Mesothelae (87 species, retaining abdominal segmentation) and Opisthothelae (over 39,000 species, without abdominal segmentation). Spiders occupy virtually all terrestrial worldwide except Antarctica, functioning exclusively as of insects and other small arthropods.

Lupettiana mordax by (c) skitterbug, some rights reserved (CC BY), uploaded by skitterbug. Used under a CC-BY license.

Amaurobius by (c) Tone Killick, some rights reserved (CC BY), uploaded by Tone Killick. Used under a CC-BY license.

Amaurobius ferox by (c) Even Dankowicz, some rights reserved (CC BY), uploaded by Even Dankowicz. Used under a CC-BY license.

Pronunciation

How to pronounce Araneae: /ɑːˈræniː.iː/

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

Images

Habitat

Found in virtually all terrestrial worldwide including forests, grasslands, deserts, wetlands, caves, and human dwellings; specific occupy distinct such as arboreal , ground litter, riparian corridors, soil burrows, and environments. Forest floors and canopies represent priority habitats for biodiversity inventory work. Some lineages have adapted to aquatic margins (Desis) or high elevations exceeding 4,000 m (Stormtropis muisca).

Distribution

distribution on every continent except Antarctica; established in nearly all land . Highest diversity in tropical and subtropical regions. Regional examples include: 1,477 recorded in Canada (45 ), with British Columbia showing 339% increase in recorded species since 1979; 667 species in Brazil; extensive undescribed diversity in Madagascar and Australia. Some families restricted to specific ecozones (e.g., southern Canadian ecozones) while others like Gnaphosidae occur from southern Arctic to tropical regions.

Diet

Exclusively predatory; feed on insects and other small arthropods. Specific prey capture strategies vary by : orb-weavers (Araneidae) construct aerial webs; jumping spiders (Salticidae) are visual active hunters; wolf spiders (Lycosidae) are ground-dwelling pursuers; -eating (Drassodidae: Callilepis nocturna) target Formicidae; pelican spiders (Archaeidae) are araneophagous, preying specifically on other spiders.

Life Cycle

Development proceeds through , post-embryo, and multiple instar stages before reaching adulthood. Females of many produce silk egg sacs; in Lycosidae, females tether egg sacs to and carry them until hatching. Spiderlings of some species (e.g., Sosippus) ride on the mother's back until their next , then may share her web for extended periods. Maternal care observed in Sosippus floridanus, with females feeding spiderlings for several months.

Behavior

Highly diverse behavioral repertoire across . Web-building range from orb webs (Araneidae) to sheet webs with funnel retreats (Agelenidae, Sosippus) to complete absence of prey-capture webs (Salticidae, Lycosidae). Venomius tomhardyi constructs silk-lined holes in tree branches for shelter. Some exhibit subsocial behavior with extended maternal-offspring cohabitation. (Pompilidae: Paracyphononyx scapulatus) manipulate spiders, allowing them to remain active while larva feeds internally, killing host only at final developmental stage.

Ecological Role

Significant in terrestrial , regulating of insects and other arthropods. Contribute to nutrient cycling through and decomposition . Serve as prey for various vertebrates and including , mantidflies (Mantispidae), and birds. Some function as indicators of quality and environmental change.

Human Relevance

Ecologically beneficial as agents of pest insects. Venom research has applications in medicine and pest management. Some (Salticidae) are established synanthropes in human dwellings worldwide. Subject of extensive scientific research, citizen science (iNaturalist records exceed 8 million observations), and popular culture. Certain large species (Theraphosidae) traded in pet markets; rare species with restricted distributions may collection pressure. Fear of spiders (arachnophobia) common despite most species posing minimal danger to humans.