Archive for August, 2010

Spider: The Crab Spider

Friday, August 6th, 2010

Crab spiders can be hard to find, but they are definitely around. The reason they can be hard to find is that most crab spider species are able to camouflage themselves with their surrounding areas. Also all of the species of crab spiders resemble crabs; hence their name. Physically the most distinctive crab like characteristics the crab spider has are their two front legs, angled outward and flat bodies. Also the movement of the crab spider mimics the movement of crabs. They walk forwards, sideways and backwards like crabs.

crab spider

Here's an up close view of a crab spider.

Crab spiders in general have neutral coloring, such as light brown to gray tones. The coloring of the crab spider allows them the ability to camouflage themselves to fit into their surroundings. Their shape, flat body and small size, averaging half an inch or smaller, can make them appear to be bird droppings. They can appear in multiple locations like bird droppings, for instance on the sidewalk, patio, roof tops, tree branches and many more locations, anywhere bird droppings can be found. This odd ability to disguise themselves as bird droppings actually gives them an advantage when hunting for food.

Even though the crab spider is smaller in size its two longer front legs make it appear to be larger than it’s described. The crab spider’s eyes are all small and act as motion detectors, which comes in handy when they are looking for prey. Crab spiders are able to crawl up places like trees, walls and posts. During the day, crab spiders sleep in an area where they blend well in order to stay out of view of predators. Once the sun falls, crab spiders will move around to find a hunting spot, or they may hunt from the location where they’ve been resting.

crab spider

Here's a crab spider after a successful hunt.

The hunting style of crab spiders is unique in that they will ambush their prey rather than chasing it down or like most other spiders they do not put a web up to trap prey. They will sit and wait in an area where they can camouflage themselves, i.e. grass, flowers, tree bark, fruit, foliage or even cracks and crevices in buildings until they can see their prey. Once an insect of their liking passes their path they will attack. For the most part crab spiders eat small- to medium-sized insects, including butterflies, ants, flies, mites, and bees. When a crab spider has caught its prey, it paralyzes it with its venom and is able to hold it down with its two larger front legs. The venom in the crab spider is powerful; it is believed they are cousins to the brown recluse spider who is very venomous. Yet, the venom of the crab spider is only effective on its prey and not people, unless a person is allergic.

The crab spider is not known for being harmful to people, but that doesn’t mean a crab spider will never bite a person. If you are bitten by a crab spider it can be very painful and can be dangerous if you are allergic to the crab spider’s venom. If you were to be bitten by a crab spider it would probably happen while you are outdoors. Crab spiders are not usually found inside homes unless they are looking for food or have been brought inside by accident. While outdoors the crab spider can be considered beneficial because it eats other insects, but that doesn’t mean you want them all over your yard. Plus there are the risks of your pets being bitten if they were to disturb a resting crab spider.

crab spider baby

Baby crab spiders look like a smaller version of the full grown crab spiders. Unlike other species they don't change in apperance, but they do molt.

Another thing to consider, like many pests that can be found in or around your home, is that these spiders reproduce, so if you find one or two you always want to do a thorough check of the surrounding areas for eggs and or babies. The crab spider’s eggs are deposited into two silken sacs, and are joined together in the center. The female will put her sac somewhere safe and usually stays near by to protect it from predators. The hatch time for the eggs depends on the environment they live in. Crab spiders can be found anywhere in the U.S. although they prefer hot and dry climates like Arizona. Once the eggs hatch the baby crab spiders look like adults just much smaller in size. Then they will molt multiple times before becoming adults. The crab spider’s life spans average about a year, and rarely lasts longer.

Always be aware of your surroundings especially outside of your home.

Images courtesy of www.creativecommons.org

Spiders: Popular Species of Crab Spiders

Friday, August 6th, 2010

Crab spiders can be found all across the country. There are over 40 species of the crab spider, but some species are seen more often than others. Also some states seem to attract particular species more than others. Some of the more popular crab spider species are what you would find outside of your house. These are the most popular species of crab spiders:

Grass Crab Spider

spider crab spider

Here's a grass crab spider walking on some grass.

Grass crab spiders have the ability to resemble grass. This species of crab spiders aren’t bright green as one might assume since they have the unique ability to blend in with grass. The grass crab spider is actually a cream to light brown color, and sometimes a semi-transparent green shade. The grass crab spider is also slimmer and longer than most other varieties. These features help them blend into their surroundings, and the longer shape can help them camouflage themselves as blades of grass.

Flower Crab Spider

spider crab spider

This flower crab spider camouflages itself so well. Looks like an early meal for the flower crab spider.

The flower crab spider is quite the opposite as the grass crab spider. The flower species are bright in color to help them blend in with flowers. Unlike the grass crab spider the flower crab spiders can be the exact same color as the flower. The most common color of flower crab spiders is bright yellow, so they can blend in with the flower petals and or pollen center. They can also have a shinier and smoother body than the other species of crab spiders. The flower crab spider is frequently found in California.

Giant Crab Spider

spider crab spider

Yikes! Looks like this giant crab spider found a way into someone's house.

Then there’s the terrifying giant crab spider. Other crab spider species look like the giant crab spider, except for the size of course. The giant crab spider is twice the size as the other crab spider species with its body about an inch or more wide. The coloring of this species is light brown to gray with the distinct dark markings on the top of the abdomen in the shape of a “Y” and dark fangs. Even though the giant crab spider is larger in size it still moves and acts the same as all of the other crab spider species. It also hunts like the other species and is actually known to be a much better hunter getting the nickname the “Huntsman” spider. One thing that enables the giant crab spider to be such a good hunter is that it’s a fast runner, which helps to conquer its prey. The giant crab spider has become native to Arizona.

Ground Dwelling Crab Spiders

spider crab spider

This ground dwelling crab spider is doing a very good job at blending into it's natural surroundings.

Ground dwelling crab spiders are able to blend in with natural surroundings. They can often be found on sandy ground, cement, gravel or areas that are black or gray. A ground dweller’s coloring is shades of browns and tones of blacks, so it can imitate the soil it’s traveling on. Michigan is an area where ground dwellers are very popular.

Bark Crab Spiders

spider crab spider

Bark crab spiders seem to be the creepiest looking of all of the species.

Since crab spiders can be known for walking up trees there is of course a bark crab spider. Blending into the natural appearance of the tree bark the bark crab spider varies from tones of browns and black, sometime having a combination of both colorings to better enable it’s blending into the bark. Some bark crab spiders can have a thorny façade. This variety of crab spider is also popular in Michigan.

Images courtesy of www.creativecommons.org and Xoque and Robert Whyte on Flickr