Agelenidae

The Agelenidae are a diverse family of spiders within the suborder Araneomorphae. They are most commonly known as funnel weavers. This name comes from the unique way they build their homes. These spiders play an important role in their ecosystems by controlling insect populations. They are found in many different environments around the world. Some species are quite small, with a body length of only 1 millimeter. Other species are much larger. For example, the species Eratigena atrica can reach a very wide leg span.

Most funnel weavers have a very specific body shape. They possess eight eyes arranged in two horizontal rows of four. Their cephalothorax, which is the front part of the body, narrows toward the eyes. Their abdomens are generally oval in shape. Many species show patterns of lines and spots on their abdomens. Some also have longitudinal lines on the dorsal surface of the cephalothorax. This is a helpful way to tell species apart. For instance, the hobo spider lacks these specific lines.

The hunting mechanism of the Agelenidae is highly specialized. They build a flat, horizontal sheet of web that is not sticky. Instead, the web is filled with entangling filaments. The spider constantly lays these fine threads down as it moves across the sheet. These filaments catch on the small projections or limbs of an insect. The web is also quite springy. The spider waits in a funnel-shaped retreat located on one side of the sheet. It stays alert for vibrations caused by prey, mates, or threats.

Speed is a vital part of how these spiders survive. Most Agelenids are exceptionally fast runners, especially on their webs. The giant house spider was once a world record holder for speed. It held a Guinness Book of World Records title until 1987. When a spider detects prey, it rushes out at high speed. It delivers a paralyzing bite using venom. In the species Agelenopsis aperta, scientists have studied a specific substance in the venom called agatoxin. After the prey is disabled, the spider drags it back into the funnel to feed.

While most Agelenids live alone, some species exhibit social behaviors. The genus Agelena includes certain parasocial spiders found in Africa. One well-known example is Agelena consociata. These spiders live in complex, communal webs. They work together to build webs and capture prey. They also engage in the communal rearing of their young. However, they do not show true eusociality like ants or bees. They do not have different castes, such as sterile workers or soldiers. In these colonies, all females remain reproductive.

The Agelenidae family is incredibly vast and diverse. It contains 100 different genera and 1,694 known species. These spiders live on almost every continent. Genera like Agelenopsis are common in North America. Other groups, such as Benoitia, are found in Africa. You can find various species in places like China, Japan, Mexico, and New Zealand. Some species are even known from fossilized Baltic amber from the Eocene epoch. This shows that the group has a very long history on Earth.

Many people encounter these spiders in their daily lives. In September, outdoor males may seek shelter inside human houses. They often nest under windowsills or near porch doors. Despite being found in homes, they are often not considered pests. They are very selective about what they eat. They do not consume large quantities of food. If they are disturbed, they usually return to their webs. They only abandon their homes if the web is completely destroyed.