Bolas Spiders (Subfamily Cyrtarachninae)

Cyrtarachninae is a subfamily of orb-weaving spiders within the family Araneidae (Order Araneae). Members of this subfamily are widely distributed in tropical and subtropical regions of the world, with some species extending into temperate areas. Cyrtarachninae are most commonly found in forests, woodland edges, shrublands, and gardens, where they inhabit vegetation and open spaces suitable for specialized prey capture.

Spiders of the subfamily Cyrtarachninae are best known for their highly specialized hunting strategies, which differ markedly from the typical orb webs of most araneids. Many species construct reduced or modified webs, and some have evolved the use of a sticky silk droplet suspended on a line, a hunting method popularly known as the “bolas” strategy. This adaptation allows them to capture flying insects, particularly moths, often by exploiting chemical cues that attract prey.

Morphologically, Cyrtarachninae spiders are generally medium-sized with robust bodies. The abdomen is often broad, rounded, or irregularly shaped and may bear lobes, spines, or distinctive patterns that provide camouflage among leaves and bark. Coloration ranges from cryptic browns and grays to more contrasting patterns. The legs are relatively long and may be held outstretched or tucked close to the body when at rest, enhancing concealment.

Behaviorally, many Cyrtarachninae species are nocturnal, becoming active at dusk or night when their primary prey is abundant. Rather than relying on large, permanent webs, they use stealth, camouflage, and specialized silk structures to capture prey efficiently. During the day, individuals often remain motionless on vegetation, blending into their surroundings.

Ecologically, Cyrtarachninae play an important role as predators of flying insects, particularly moths, and contribute to regulating insect populations in their habitats. The subfamily includes distinctive genera such as Cyrtarachne and Mastophora and represents one of the most unusual and behaviorally specialized lineages within the orb-weaving spiders.