Guide to Identifying Spiders With Red and Orange Abdomens

Identifying Spiders with Red Abdomens

While the majority of spiders have dark-colored abdomens, some species exhibit bright reddish or orange patterns. These eye-catching markings can help identify different types of spiders. Learning to recognize spiders with red butts can satisfy your curiosity when you spot these colorful creatures in your home or garden.

Spider abdomens come in a rainbow of different hues and patterns. Red, orange, yellow, and white markings are common in many species. These vibrant colors and designs serve a range of purposes, like attracting mates, warning off predators, and camouflaging in certain environments.

Read on to discover some of the most common spiders characterized by reddish or orange abdomens and backsides. Once you know what to look for, you can readily identify these flashy spiders.

Common Spiders With Red Abdomens

1. Black Widow Spider

This notorious spider is easily identified by the red hourglass shape on its underside. There are a few different widow spider species in North America. The western black widow (Latrodectus hesperus) has a shiny black body with a brightly colored red pattern on the abdomen.

While female widows have the classic hourglass, males have lighter coloring with red and white bands and spots on the back. Widows build messy cobwebs and prefer dark isolated spaces. Though venomous, they are not aggressive and only bite in self-defense.

2. Redback Spider

Closely related to black widows, redback spiders (Latrodectus hasselti) are native to Australia. The females are black with a prominent red stripe on the upper side of the abdomen. These spiders build irregular webs in protected spots close to the ground.

Like other widow spiders, redbacks have neurotoxic venom that can cause severe pain and illness in humans, though antivenom makes bites very treatable. Redbacks are not usually aggressive but may bite in defense of their web.

3. Red Spotted Ant Mimic Spider

Also going by the name antmimic spider, Castianeira longipalpa exhibits a red-orange abdomen with white spots mimicking ants. This clever camouflage helps the spider ambush ant prey. They do not build webs and hunt on the ground.

These spiders use venom to capture prey but are not considered dangerous to humans. You can find them under debris, logs, and rocks in most of North America.

4. Spined Micrathena Spider

This spider has a black thorax and legs with a brightly colored red, orange, or yellow abdomen. Micrathena gracilis exhibits pointed spines on its abdomen. The colorful pattern acts as a warning signal, advertising that this spider is toxic if eaten by predators.

Spined micrathena weave small but impressive circular webs decorating trees, shrubs, and vegetation. They prey on flying insects caught in their webs. Though venomous, they are not aggressive toward humans.

5. Jumping Spiders

Many jumping spider species have abdomens with vibrant red, orange, and metallic scales or hairs. These include bold jumpers (Phidippus audax), Regal jumpers (Phidippus regius), and Daring jumping spiders (Phidippus audax).

Their colorful markings are thought to attract mates, and some can change color. Jumping spiders do not build webs to catch prey. Though they have excellent vision and spring on victims, their small fangs cannot pierce human skin.

6. Ladybugs

Sometimes mistaken for spiders, adult ladybugs have characteristic domed, oval-shaped bodies with black spots on red wing covers. Baby ladybugs, called larva, look more spider-like, with elongated bodies and multiple legs.

However, ladybugs only have six legs versus eight on spiders. And they are harmless beneficial insects that feed on plant pests like aphids. Brushing them away is the best strategy if they end up on your skin.

Funnel Weavers and Grass Spiders

Some funnel weaver and grass spider species also showcase reddish or orange patterns on their abdomens. Examples include the barn funnel weaver (Tegenaria domestica) and cardinal spiders (Tegenaria parietina). Both build large, sheet-like webs to trap prey.

The orange-brown striped legs and muted orangey-red abdomen help camouflage grass spiders (Agelenopsis species) in garden environments. And funnel weavers like the hobo spider (Eratigena agrestis) have varying degrees of patterning.

These spiders are not dangerous to humans, but may bite if threatened. Their venom typically only causes mild reactions.

Identifying Spider Features

When attempting to identify a spider, looking at more than just abdomen color is important. Consider key features like:

Body Shape

Does the spider have an oval-like body (orb weavers, widows) or a long narrow one (cellar spiders)? What about leg length and thickness?

Leg Arrangement

The arrangements of a spider's eight legs can also offer clues. Most hold their legs close together, while crab spiders spread them apart.

Web Types

Look for the presence and characteristics of webs. Funnel webs, orb webs, sheet webs, cobwebs all provide hints about species.

Eye Patterns

The number and arrangement of a spider's eyes aids identification. Jumping spiders, for example, have large front-facing eyes.

Movement Style

Does the spider rapidly jump and leap or slowly crawl? Quick speed indicatesjumping spiders vs. the slow, steady movement of ambush hunters like widows.

Combining these visible features with red markings on the abdomen can help accurately identify different species. Location, habitats, and behaviors offer additional clues in pinning down spider species.

Common Questions About Spiders With Red Butts

Why Do Some Spiders Have Red Butts?

There are a few key reasons spiders exhibit bright red or orange patterns:

• Camouflage - orange/red markings help certain spiders blend into leaves, flowers, bark, or soil in their habitats.
• Warning coloration - vibrant patterns on venomous species signal toxicity.
• Attracting mates - many males have colorful patterns to attract female attention.
• Temperature regulation - some spiders can change color to control body heat.

Are Spiders With Red Butts Dangerous?

Some potentially dangerous spiders do have reddish markings, like black widows and redback spiders. The majority of spiders with orange-red abdomens are harmless to humans, but it's wise to teach children not to touch any spiders.

Why Do Spider Abdomens Change Color?

For some species, shifting abdomen color is a means of temperature regulation, communication, or other functions. Color changes happen through repositioning pigment-containing cells or altering reflective properties of hairs.

Can Spider Bites Cause Red Marks?

Though rare, spider bites can result in a red bump or spot on the skin, along with pain, itching, and swelling. Redness around a bite could indicate a mild infection or reaction. Seek medical advice if bitten by any spider.

Appreciating Red-Bellied Spiders

While the thought of spiders makes some people squeamish, these fascinating creatures play important ecological roles. Most species with red or orange patterns on their abdomens are not considered dangerous to humans.

Their colorful markings are vital for camouflage, communication, temperature control, and warning off predators in nature. With over 40,000 diverse spider species in the world, there's an exciting array of colors and patterns to discover.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.