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Grass Spider (Agelenopsis)

The American grass spider is a fascinating creature from the funnel weaver family, mainly found in various regions of the United States. This post offers a deep dive into intriguing facts about this spider, helping you understand its unique world. 

Scientific Classification

Grass Spider

List of Species Belonging to the Genus

Agelenopsis actuosaAgelenopsis aleenaeAgelenopsis aperta
Agelenopsis emertoniAgelenopsis kastoniAgelenopsis longistyla
Agelenopsis naeviaAgelenopsis oklahomaAgelenopsis oregonensis
Agelenopsis pennsylvanicaAgelenopsis potteriAgelenopsis riechertae
Agelenopsis spatulaAgelenopsis utahana 

Physical Description & Identification

Adults

  • Size: They are moderately big in size, having a body length of about 0.74 inches (19 mm), with the males being smaller in size than the females.
  • Color: They are mostly brown in color while some species may also be seen in shades of gray, ivory, beige, black, or a blend of various shades.
  • Other characteristics: They have eight eyes arranged in rows of three, two on top, four in the middle, and two at the bottom. These species have two prominent spinnerets at the back, indistinct bands on the legs as well as two dark bands on each side of its cephalothorax.
Grass Spider Size

Eggs                  

The eggs are big and round, lying within a disc-shaped sac.

Spiderlings

The spiderlings of this species go through a lot of molts after emerging from the egg sac until they reach adulthood.

The Web

The funnel spider spin sheet webs have a funnel shelter on one of the edges. Their webs are non-sticky, lacking adhesive capacity, however, the grass spiders make up for this flaw by running fast while getting after their prey.

Grass Spider Web

Are American Grass Spiders Venomous?

Yes, American Grass Spiders have venom, but it’s mainly for subduing their prey and is not harmful to humans.

Can American Grass Spiders Bite?

The funnel web grass spiders are not harmful and rarely bite unless provoked or agitated. Moreover, their bite does not cause harm to mankind apart from the basic symptoms of swelling and redness.

Male Grass Spider

Photo Credit: Ron Wolf

Ecological Importance and Behavior of Grass Spider

American grass spiders play a vital role in controlling insect populations, contributing to the ecological balance in their habitats. They exhibit nocturnal behavior, being most active during the night, and they rely on their agility and speed to hunt. Their unique funnel-shaped web serves both as a hunting ground and a sanctuary, allowing them to quickly respond to potential threats or prey.

Natural Predator and Prey-Predator Dynamics: These spiders face threats from various predators such as lizards, chameleons, and geckos. The dynamics between them and their predators are a fascinating aspect of their ecosystem, showcasing the delicate balance between hunter and hunted.

Relationship with Humans: Grass spiders are commonly found outdoors amidst tall grasses and shrubs. While their presence may go unnoticed, they play a crucial role in managing pest populations, making them beneficial neighbors to humans. Misidentification is common, especially with wolf spiders and the venomous brown recluse, but understanding their unique characteristics can help in distinguishing them and appreciating their role in nature.

Quick Facts

Lifespan1-2 years
DistributionParts of the United States and Canada
HabitatMostly outdoors amidst tall grasses, and the shrubby areas
Common PredatorsLizards, chameleons, and geckos
Diet Small insects and other spiders
Picture of a Grass Spider

Did You Know

  • C. G. Giebel described these spiders for the first time in 1869.
  • Their genus name is a blend of Agelena and opsis, with the former being referred to the Eurasian grass spiders and the latter a Greek word, meaning to have a similar look.
  • The grass spider is often confused with the wolf spiders as both of them have similar color patterns around their head region, though the latter is more harmful than the former.
  • Because of its brown body, this species may even be mistaken for the venomous brown recluse, though the former can be mostly distinguished by the dark stripes running through its abdomen.

In conclusion, the American grass spider stands as an intriguing and vital component of its ecosystem.

Funnel Web Grass Spider

The American grass spider is a fascinating creature from the funnel weaver family, mainly found in various regions of the United States. This post offers a deep dive into intriguing facts about this spider, helping you understand its unique world. 

Grass Spider

List of Species Belonging to the Genus

Agelenopsis actuosaAgelenopsis aleenaeAgelenopsis aperta
Agelenopsis emertoniAgelenopsis kastoniAgelenopsis longistyla
Agelenopsis naeviaAgelenopsis oklahomaAgelenopsis oregonensis
Agelenopsis pennsylvanicaAgelenopsis potteriAgelenopsis riechertae
Agelenopsis spatulaAgelenopsis utahana 

Physical Description & Identification

Adults

  • Size: They are moderately big in size, having a body length of about 0.74 inches (19 mm), with the males being smaller in size than the females.
  • Color: They are mostly brown in color while some species may also be seen in shades of gray, ivory, beige, black, or a blend of various shades.
  • Other characteristics: They have eight eyes arranged in rows of three, two on top, four in the middle, and two at the bottom. These species have two prominent spinnerets at the back, indistinct bands on the legs as well as two dark bands on each side of its cephalothorax.
Grass Spider Size

Eggs                  

The eggs are big and round, lying within a disc-shaped sac.

Spiderlings

The spiderlings of this species go through a lot of molts after emerging from the egg sac until they reach adulthood.

The Web

The funnel spider spin sheet webs have a funnel shelter on one of the edges. Their webs are non-sticky, lacking adhesive capacity, however, the grass spiders make up for this flaw by running fast while getting after their prey.

Grass Spider Web

Are American Grass Spiders Venomous?

Yes, American Grass Spiders have venom, but it’s mainly for subduing their prey and is not harmful to humans.

Can American Grass Spiders Bite?

The funnel web grass spiders are not harmful and rarely bite unless provoked or agitated. Moreover, their bite does not cause harm to mankind apart from the basic symptoms of swelling and redness.

Male Grass Spider

Photo Credit: Ron Wolf

Ecological Importance and Behavior of Grass Spider

American grass spiders play a vital role in controlling insect populations, contributing to the ecological balance in their habitats. They exhibit nocturnal behavior, being most active during the night, and they rely on their agility and speed to hunt. Their unique funnel-shaped web serves both as a hunting ground and a sanctuary, allowing them to quickly respond to potential threats or prey.

Natural Predator and Prey-Predator Dynamics: These spiders face threats from various predators such as lizards, chameleons, and geckos. The dynamics between them and their predators are a fascinating aspect of their ecosystem, showcasing the delicate balance between hunter and hunted.

Relationship with Humans: Grass spiders are commonly found outdoors amidst tall grasses and shrubs. While their presence may go unnoticed, they play a crucial role in managing pest populations, making them beneficial neighbors to humans. Misidentification is common, especially with wolf spiders and the venomous brown recluse, but understanding their unique characteristics can help in distinguishing them and appreciating their role in nature.

Quick Facts

Lifespan1-2 years
DistributionParts of the United States and Canada
HabitatMostly outdoors amidst tall grasses, and the shrubby areas
Common PredatorsLizards, chameleons, and geckos
Diet Small insects and other spiders
Picture of a Grass Spider

Did You Know

  • C. G. Giebel described these spiders for the first time in 1869.
  • Their genus name is a blend of Agelena and opsis, with the former being referred to the Eurasian grass spiders and the latter a Greek word, meaning to have a similar look.
  • The grass spider is often confused with the wolf spiders as both of them have similar color patterns around their head region, though the latter is more harmful than the former.
  • Because of its brown body, this species may even be mistaken for the venomous brown recluse, though the former can be mostly distinguished by the dark stripes running through its abdomen.

In conclusion, the American grass spider stands as an intriguing and vital component of its ecosystem.

Funnel Web Grass Spider