What is a spider?

Spiders are classified in the animal kingdom, arthropod phylum and arachnida class. 

Arachnids are defined by having:

• Four pairs of legs
• Two body segments (called “cephalothorax” and “abdomen”)
• No wings or antennae

Also:

• Most (but not all) spiders have 8 eyes
• All kinds of spiders make silk, but not all use it for making webs

What do spiders do in the garden?

Spiders are very common to find outside and in the garden. Are they helpful or harmful, though?

Fortunately, spiders don’t eat your garden plants. They are much more interested in eating insects that may pester you (like mosquitoes) or your garden.

Here’s an interesting spider experiment that scientists tried about 30 years ago:

• Scientists had multiple garden plots
• They added flowers, mulch, or both flowers and mulch, to some of the garden plots (and kept others the same)
• They noted that in plots with added flowers and mulch, there were more spiders (the spiders liked the additions to the plot)
• In one of the flower and mulch plots, they removed spiders from the area
• They then compared how much damage was done to plants by insect pests
• The results? Flowers and mulch attracted spiders, and spiders stopped or reduced the pests causing damage to plants
• Conclusion? Spiders are beneficial in the garden by eating insects that would otherwise eat your garden vegetables!

Source: Ecology journal, “Prey Control by an Assemblage of Generalist Predators: Spiders in Garden Test Systems,” by Susan E. Riechert and Leslie Bishop, August 1990

Did you know?

Not all arachnids are spiders. The daddy-long-legs “spider” is actually an arachnid known as a “harvestmen”. They are related to spiders, but are considered to be a different classification based on their body shape.

Another Spider Fact:

The fear of spiders is called “arachnophobia”.

When you encounter spiders in your garden, though, there is no reason to be afraid! Instead, consider sitting and watching them for a bit, and see if they will capture an insect or build their webs.

Are spiders dangerous?

There are some types of spiders that are best to avoid, as they could hurt you if they bite. Fortunately the most common spiders in the United States that are considered dangerous are not likely to be encountered in your garden.

What makes these spiders dangerous? It’s because they are “venomous”, meaning that they produce venom to inject through their bites. The venom is really meant for their prey, but if they bite humans, it will also have an effect on us.

The most well-known venomous spiders in the United States are the black widow (and its relative the northern widow) and the brown recluse. If you recognize these spiders and find one, never try to touch it. Instead immediately tell an adult what you found, and where it is.