Spider territoriality is complex, as behavior is remarkably diverse and varies by species and environment. While many spiders lead solitary lives, some exhibit territorial behaviors, while others engage in communal living. Understanding this spectrum involves examining the resources spiders defend and their interactions.
Defining “Territory” in the Spider World
For spiders, “territory” differs from many animals. Instead of defending a broad geographic area, spiders typically focus on protecting critical resources for survival and reproduction. These resources can include their web, a burrow, a specific hunting ground, or access to mates. For web-building spiders, the web itself represents their primary territory, serving as both a hunting tool and a home.
Defensive behaviors can range from subtle displays to direct physical confrontation. A spider might shake its web to deter an intruder, or it might engage in aggressive posturing. In some cases, especially when another spider of the same species encroaches, actual fighting can occur. This defense ensures the spider retains access to its food source and a safe refuge.
Variations in Territorial Behavior Among Spiders
The degree of territoriality varies widely across different spider species. Many solitary spiders, such as funnel-web spiders, actively defend their burrows or lairs against perceived threats. Tarantulas, known for their burrowing habits, also defend their burrows, considering their immediate living space as their territory and reacting to any intrusion.
Jumping spiders, which are active hunters rather than web-builders, can also display territorial tendencies, often defending a small, localized area. Even common house spiders may show territoriality towards other spiders of their own kind, typically establishing their individual nests far apart to avoid conflict. The availability of prey can influence how territorial a spider becomes; abundant food might lead to less territorial behavior, allowing for closer proximity between individuals. Mating strategies also play a role, with males sometimes engaging in aggressive displays over access to females or defended spaces.
Cooperation and Communal Living
Despite the solitary nature of most spiders, a small number of species live communally. Only 25 to 60 of over 53,000 described species are considered social. These social spiders share large, intricate webs and engage in collective activities. Examples include species like Anelosimus eximius, Stegodyphus mimosarum, and certain Philoponella species.
Communal living offers several advantages, including the ability to construct massive shared webs, sometimes even over 20 feet across. These larger webs can capture prey significantly bigger than what a solitary spider could manage, such as large insects, or even small vertebrates like birds and bats. Shared web maintenance, cooperative hunting, and collective defense against predators are common benefits. Additionally, social spiders often share in the care of eggs and spiderlings, contributing to the survival of the group. This cooperative lifestyle demonstrates a complex social structure that contrasts sharply with the territorial instincts of many other spider species.