Pest Library

Characteristics

The longlegged sac spider is one of the most easily recognized spiders because of their very long anterior legs. The two most common species of the Cheiracanthium are C. inclusum, which is the lone native species found in the U.S., and the C. mildei that originated from Europe and is now found throughout the northeastern part of the U.S.

• Females are 1/5 to 2/5 inch in length
• Males are 4/25 to 3/10 inch in length
• C. inlusum has yellow to cream hue with dark brown jaws
• C. mildei has a modest greenish tinge on its abdomen and a pale yellow cephalothorax
• They have a modest darker dorsal stripe moving lengthwise to the abdomen

Habitat

The longlegged spiders can be found both indoors and outdoors. Their retreats that are made of silk tent-like shelters can be under objects such as under leaf litter, under the bark of trees and stone, lumber left outside and the likes. They can also be found in the corners of walls and ceilings.

Behavior

You may not be able to find these spiders during the day because they are nocturnal. They will just stay inside their retreats until it is time for them to wake up and find food. You may also find a couple of retreats since they seldom reuse a retreat.

Food

These longlegged sac spider are not like many spiders that construct silken snares, but they normally hunt for their food on foot. With the use of their tarsal claw tufts that are compact with hairs, these help them to grip even on slick surfaces, which is why homeowners can see them running across the ceiling with ease.

Life Cycle

Unlike other spiders, the longlegged female spiders do not die after they have eggs. In fact, they will remain with their young once they come out and take care of them for a bit. It is during the months of June and July that the female spiders deposit her eggs in her silken retreat. Once done, she will remain with her eggs to protect them.

The C. inclusum are commonly found undersides of leaves or other foliage where they can deposit their eggs. The C. mildei that are common in homes will lay eggs indoors. Once the eggs hatch, the spiderlings will still remain within the silken retreat, but will soon venture out during night time to search for food. They will come back at daybreak to their retreat to get protection.

After they shed their skin, they will leave their retreat to find their own place by crawling to the upper part of a stem and create a string of silk which will help them move to a new place. And once, the first brood is gone, the mother spider can have her second batch of eggs.

Other Information and Tips

Since these spiders stay in higher places when they are indoors, it is unlikely that they will get into human contact. But, because these two species, the C. inclusum and the C. mildei, are commonly found indoors, they are known to be responsible for household spider bites, which can be compared to a sting of a hornet.

Those who are bitten by the C. inclusum may experience intense itching and burning at the bite site. Although they are mildly venomous to humans, some individuals may be sensitive to the venom and may experience symptoms that include fever, nausea, intense pain at the bite site, muscle cramps and malaise. The C. midei are the most aggressive and may even bite without reason.

Photo by JonRichfield (Own work) [CC BY-SA 3.0], via Wikimedia Commons / resized from original