Red Spiders (In the House and Outside): Pictures and Identification

Red-bodied arachnids belonging to the Nesticodes genus are commonly found indoors as spiders. These tiny creatures can be found hiding in door frames, window corners, under furniture, and in dark areas. Some species of red spiders, however, also inhabit outdoor areas. Some examples of red spiders include the small crimson grass spider, the hairy leaping crimson and black cardinal spider, and the large crimson-brown woodlouse spider.

While most people tend to get nervous when they see spiders scurrying across the floor, the presence of a red house spider can be particularly intimidating. The red color of these spiders may be alarming because it is usually a warning sign in nature. Moreover, some may worry that red spiders are venomous or may bite if touched.

Therefore, it is crucial to identify the specific species of red spider you encounter in and around your house. This is especially important to avoid mistaking a harmless red spider for a dangerous brown recluse spider. This article provides descriptions and photographs of some of the most common types of red spiders to aid in their identification.

Are Red Spiders Venomous?

It is a common misconception that all red spiders are poisonous. While it is true that some red spiders are venomous, most species do not pose a significant threat to humans. Like all spiders, red spiders do bite and inject venom, but the majority of red spider bites are not dangerous.

Two examples of indoor red spiders that may bite humans and are venomous are the common red house spider and the woodlouse spider. Although their bites may cause discomfort and redness, they are not typically severe and do not require medical attention, unlike the bite of a black widow spider which can be extremely painful and requires immediate medical attention.

Red House Spiders – The Most Common Spiders Found Indoors

The red house spider, scientifically known as Nesticodes rufipes, is a commonly found red spider species indoors. They prefer to reside in dark, cool places like crevices, cracks, and gaps. These small spiders are easily recognizable with their bulbous dark red abdomen and reddish-orange spiny legs.

Red house spiders belong to the comb-footed spider family and are characterized by the comb-like spines on their legs. Their webs are usually messy and tangled, providing protection from predators. These spiders spend most of their time waiting for prey to get trapped in their webs, which take up almost half of their time.

How to Identify Red House Spiders

Red spiders can be identified by their distinctive red color, which can range from bright red to reddish-brown, as well as their eight legs, six or eight eyes, and chelicerae.

Additionally, the markings on their body, the shape of their body, and whether they are hairy or smooth can aid in their identification. The type of web the spider creates is another way to distinguish its species. Red orb spiders create symmetrical circular webs, while red house spiders create messy, irregular webs.

Red Spider Mite (Tetranychus urticae) – Tiny Red Spider

Red spider mites are tiny pests that can cause significant damage to plants. They are small and difficult to see with the naked eye, but their crimson-colored bodies and tiny white legs make them distinguishable. These mites, belonging to the arachnid class of spiders, have eight legs and spin webs on plants. Red spider mites feed on the sap of plant tissue by piercing it with their mouthparts, which can lead to discoloration, leaf drop, and even death of the plant if not treated.

Detecting red spider mites on plants can be quite challenging as they are only about 0.016 inches (0.4 mm) long and can hardly be seen with the naked eye. However, one can look out for signs of infestation, such as the presence of fine silky webs or threads hanging from the leaves of plants. Another indication of red spider mite activity is the appearance of tiny red dots on the leaves of plants.

Types of Red Spiders (With Pictures) – Identification Guide

Now, let’s explore the procedures for recognizing the kinds of red spiders that may be seen in your house or yard.

Red House Spider (Nesticodes rufipes)

The red house spider is one of the most commonly found red spider species inside houses. They are identified by their dark red body and reddish-brown legs. These small spiders typically have a body length of 0.2 to 0.33 inches (5 to 8 mm) and can resemble widow spiders due to their red and black coloring.

Red spiders, particularly red house spiders, are commonly found in dark and cool corners of a house, usually near windows and doors. They are solitary creatures and create tangled and messy webs in their preferred habitat. Red house spiders have reddish-brown or orange-brown bodies and are often referred to as tangle-web spiders, comb-footed spiders, or cobweb spiders.

Although red house spiders can bite humans, their venom is non-necrotic and not as harmful as other spider species like the brown recluse or black widow spiders. Red house spiders will usually flee rather than attack if they feel threatened, and their bites cause only temporary pain and swelling that can last for a few hours. However, it is still recommended to avoid disturbing their nests or webs to prevent any unwanted bites.

Red Spider Identification

The globe-like dark red abdomen and cephalothorax, spiky orange-red legs, and tangle of tangled threads distinguish a red house spider.

Red House Spider Facts

Red house spiders belong to the family Theridiidae and can be found in temperate regions worldwide. The Nesticodes genus consists of only one species, the red house spider.

While they tend to prefer warmer climates, they can also be found in colder regions, particularly inside homes.

Red house spiders may resemble black widow or brown widow spiders, but they lack the characteristic hourglass patterns on their bodies.

Blacktailed Red Sheetweaver Spider (Florinda coccinea)

The black-tailed red sheetweaver spider is characterized by its bright red color and a black mark on its tail end. With its spindly legs, the spider appears larger than it actually is and measures around 0.12 to 0.16 inches (3 to 4 mm). The spider has eight eyes, as well as eight legs, which is typical of spiders.

Red grass spiders, also known as sheetweaver spiders, are usually found outside in areas such as lawns, grasslands, and weeds. They are known for their webs, which are horizontal sheets of sticky silk. These spiders are not commonly found inside homes.

Red Spider Identification

The dazzling red body, dark legs, and large black patch at the blacktailed red sheetweaver spider’s rear are all distinguishing features.

Woodlouse Spider (Dysdera crocata)

The woodlouse spider is a dark red spider with a glossy brownish abdomen. It is larger than the red house spider, measuring around 0.43 to 0.6 inches (11 to 15 mm) in length. This species has transparent orange legs, an elongated black and red cephalothorax, and a duller abdominal area. They are called woodlouse spiders because their diet consists of pillbugs or woodlice.

Red woodlouse spiders prefer outdoor spaces and hide under rocks, plant pots, and leaf litter where woodlice reside. They are active during the day and hunt at night instead of spinning webs to catch their prey. Similar to other red spiders, the red woodlouse spiders are venomous and can bite. However, their venom is not necrotic, and the bite usually causes redness, itching, and discomfort.

Red Spider Identification

With crimson or orange legs and a grayish brown to yellow-brown abdomen, the red woodlouse spider is a slender dark red spider. Prominent chelicerae and six eyes are two more identifying features.

Types of Red-Orange Spiders (With Pictures) – Identification Guide

A reddish-orange hue with black markings distinguishes many spider species. Orb-weaver spiders and jumping spiders make up the majority of these red-orange spiders.

Cardinal Jumper Spider (Phidippus cardinalis)

The cardinal jumper spider is a tough, orange-red spider with a fuzzy, oval abdomen and a large cephalothorax. The spider resembles a miniature tarantula, with hairy legs and a row of eyes with two middle eyes staring out. This predatory spider lives in the eastern United States, and it feeds on fruit flies, cockroaches, and small crickets.

Despite its strong chelicerae, the red-orange cardinal jumper spider’s bite is not harmful to humans.

Red Spider Identification

The body of the cardinal jumping spider is hairy, and its legs are black or grayish-black. It features two large middle eyes in addition to a row of eyes.

Whitman’s Jumping Spider (Phidippus whitmani)

The male Whitman’s jumping spider has an identifiable orange-red cephalothorax and an oval abdomen covered in dense red hairs. Its legs, covered in fine gray hair, create an attractive contrast to its velvety red and gray body. This tiny spider measures only 0.4” (10 mm) long and has two prominent middle eyes like the related cardinal jumper.

Whitman’s jumping spiders are commonly found outside in grasslands and open woodlands. They use their exceptional vision to hunt insects such as flies and moths instead of constructing complicated webs to capture them.

While the red Whitman’s jumper spider can deliver a painful bite if it feels threatened, its venom is harmless to humans and causes only mild redness and itching for approximately an hour.

Red Spider Identification

The bright red or deep-orange body, four eyes on top of its head, and hairy gray legs distinguish Whitman’s jumping spider.

Rubens Orbweaver (Hypsosinga rubens)

The Rubens orb-weaver is a visually stunning spider that boasts a bright red-orange ball-shaped abdomen, a small head, and glossy jet-black legs. Measuring only 0.18” (4mm) in length, this shiny red spider can be found in garden areas where it spins elaborate orb webs to capture prey.

Named after the web it creates, the Rubens orb-weaver produces intricate circular webs made of non-sticky silk, with added sticky droplets to trap flies. These beautiful webs are often found between the stems of plants or shrubs.

Red Spider Identification

The Rubens orb-weaver is identified by its bulbous orange-red abdomen and jet-black legs.

Red Spiny-Backed Orb Spiders (Gasteracantha)

Red spiny-backed orb spiders are among the unique spider species that can be found in gardens. These spiders are known for their six spines that adorn their oval abdomen,

giving them a crab-like appearance. They are also referred to as crab spiders because of this resemblance. With over 70 species of spiny-backed orb spiders, their color range varies from white to black with dots, and there are also various shapes and sizes of red spiny-backed spiders.

Red Spiked Orb Weaver Spider (Gasteracantha falcicornis)

The red spiny orb-weaver is a unique spider with bright red coloring and black spines on its abdomen that curl like a crab’s claws. The oval-shaped body of the spider is covered in tiny hairs and has two reddish-burgundy horizontal stripes along with rows of black marks. The spider’s head is dark maroon in color.

The red spiny orb-weaver is small, measuring between 0.39″ to 0.51″ (10–13 mm) in width and 0.19″ to 0.35″ (5–9 mm) in length. The spider spins an orb web to catch prey, which can be found in shrubby gardens and woodlands.

Red Spider Identification

Its deep red body with long curved horn-like spines erupting from its abdomen distinguishes the Red spiked orb weaver spider from other spiders.

Red Thorn Spider (Gasteracantha versicolor formosa)

The red thorn spider is a brightly colored red orb-weaver spider with orange stripes and dimpled spots on its back. This strange-looking spider has two long curving horns protruding from its sides, as well as two smaller spiky spines at the front and rear. It is also known as the long-winged kite spider due to its kite-like appearance when seen from the front.

The red thorn spider has a hard red abdomen projecting over the cephalothorax, and the female is the largest and most vibrant of the species. Excluding the two lengthy thorny projections, the red thorn spiny orb-weaver spider measures 0.31″ to 0.39″ (8 to 10 mm) at its widest point.

Red Spider Identification

The red thorn spider’s crimson abdomen, six exterior spines, and crimson legs distinguish it from other species.

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