St. Andrews Cross (Argiope keyserlingi)

Did you know there’s a spider named after a cross pattern? It’s called the St. Andrews Cross spider. This spider lives in Australia and makes a web that looks like a special cross. Keep reading, and you’ll discover more cool facts about this unique spider!

Physical Description and Identification

Adults

• Size: Females are 0.39-0.62 in (1-1.6 cm) and males are 0.11-0.15 in (0.3-0.4 cm).
• Color: Females’ carapaces are yellow and gray with black and red bands, while the upper part of the having two yellow horizontal stripes. Males differ in coloration of the body as they are a combination of cream and brown with the same longitudinal stripes.
• Other Characteristic Features: The spiders’ legs are paired when they sit.

Eggs

Post mating, the female spider lays 400-1,000 eggs in a sac and places it (the sac) on the web. Hatching occurs in autumn.

Spiderlings

Spiderlings overwinter in the sac and come out in the following spring.

The Web

Female spiders build orb webs, sizing 1.4-1.9 in, and the highlighting point is the X-shaped motif in the middle, made with two stabilimentum lines. Sometimes juveniles may create spiral patterns. It takes nearly a day to complete a single web.

The web attracts the prey as the UV rays reflect in the silk threads and make the web bright and conspicuous against its background.

Are St. Andrews Cross Spiders Venomous?

Yes, St. Andrews Cross Spiders are venomous. Their venom helps them catch bugs to eat, but it’s not very strong for humans.

Can St. Andrews Cross Spiders Bite?

Yes, St. Andrews Cross Spiders can bite. They’re usually calm, but if they do bite, it’s mostly like a tiny pinch and not toxic or harmful to us.

Ecological Importance and Behavior of St. Andrew’s Cross Spider

St. Andrew’s Cross Spiders are integral to their ecosystems as they help control insect populations. Their presence in open forests, shrubby areas, rainforests, and even around homes indicates their adaptability and ecological significance.

Natural Predators: Birds and praying mantises are known predators of the St. Andrew’s Cross Spider, playing a crucial role in the food web by keeping spider populations in check and ensuring ecological balance.

Prey-Predator Dynamics: Their role in the ecosystem as predators of insects like beetles, butterflies, moths, and flies is balanced by their status as prey for larger animals. This dynamic is essential for the health of their habitats.

Relationship with Humans: These spiders are generally non-aggressive towards humans and will only bite if provoked, resulting in nothing more than a minor pinch. They are often welcomed in gardens due to their pest control capabilities.

Quick Facts

Did You Know

• The spider sits on its web as its legs are aligned with the specific pattern for a larger appearance.
• Multiple males often cohabit with a female in her web.
• The scientific name is given after the famous arachnologist, Eugen von Keyserling.

In conclusion, the St. Andrew’s Cross Spider is a remarkable arachnid with a distinct web pattern and significant role in controlling insect populations.