Brown Recluse Spider Appearance and Preventing an Infestation

The Brown Recluse spider or ‘fiddle back’ is listed among the most noxious spiders in the world.  Yet for being one of the more deadly spiders for its highly necrotic bite, it is not aggressive, hence its name.  The Brown Recluse would rather stay concealed then actively seek out prey or enemies. It has a relatively small distribution area, yet manyAdelaide Spider Control workers are called to houses frequently because a homeowner has mistaken a brown colored spider for the Brown Recluse.  The notable difference between a brown spider and the Brown Recluse is that Recluse spider has 6 eyes rather than 8 and that a violin or ‘fiddle-shaped’ mark appears on the cephalothorax, that is the fused head and thorax.  If the spider has recently molted, the markings will appear faint or non-existent so it is always best practice to stay away from any spiders.

Appearance

The ‘violin’ is not just limited to the Brown Recluse, but a characteristic shared by some of the other species in the recluse family.  The neck of the violin points to the rounded, fuzzy abdomen. The Brown Recluse’s color may run from a light tan to a dark brown. Typically with each molting, the spider will grow a bit darker.  This spider appears to have a velvet-like covering which is a result of the numerous fine hairs that line theCephalothorax and the legs.

When the legs of the Brown Recluse are fully extended, the total body size is measured about 3/8 inches long.  The thin legs on the male body are longer than the legs of a female spider, but the male’s body length is shorter.  The skilled eye of an expert will need to examine the spider’s reproductive organs under a high-power microscope.

Life Cycle

The Brown Recluse spider begins its journey of life in an egg sac.  A female spider will lay approximately 50 eggs within each egg sac.  These sacs are off-white in color and about 2/3 inches in diameter the female is able to lay several egg sacs over the course of the warm weather months as long as conditions are favorable.  In about one month’s time, the spiderlings will hatch from the egg sac but unlike most spiderlings, juvenile Brown Recluse spiders do not balloon away from the nest on silken threads. This greatly diminishes their habitat area.

In 1 year’s time, the juvenile Brown Recluse will reach maturity.  During this time, they will have molted between 5 to 8 times until they have grown to be almost the size of a US quarter.  Depending on food availability and favorable habitat, an adult Brown Recluse may live as long as four years, though the average is two years.

Habitat

The Brown Recluse spider is a solitary figure that would rather seek out a dark, vacant corner to spin its sticky web and gather food.  If a Brown Recluse is found wandering far from its web it is typically a male in search of a mate. Content both indoor and outdoor, they rely on human-altered habitats for a good source of food.  The spider forages in the evening and overnight hours and according to a recent study from the University of Kentucky, they prefer dead insects. Windows, corners blocked by heavy furniture, and light fixtures tend to attract and collect insects trapped inside residential dwellings so the Brown Recluse is likely to find a snack there.  Searching for food is an instinct of every animal, but the Brown Recluse spider can last up to six months without eating.

If living in an indoor environment, the Brown Recluse may be spotted in attics and basements, linen closets and shoeboxes, cellars and A/C vents.  Outdoors, the spider may make its home among woodpiles, downed trees, or stone piles. 

Usually, when a Brown Recluse has been spotted outside of its normal geographic habitat it is because it takes refuge in a storage container and has been transported by an unknowing human.

Preventing an Infestation

•         Inspect windows and door frames.  Ensure that screens are tight-fitting and that any cracks are sealed over.  Ensure the draft guard at the bottom of the doors seal tightly when the door is in a closed position.
•         If floodlights run throughout the night, use yellow or sodium vapor light bulbs as fewer insects are drawn towards those blubs.
•         When storing cardboard boxed items away in closets seal off the corners and flaps with tape.
•         If possible use lidded plastic containers to house items stored in attics or basements.
•         Do not allow clutter to pile up.  The Brown Recluse likes the stability that discarded, ignored items provide.  Discard or donate old clothing, bed linens, or toys that are never used.
•         Keep window sills clear of dead bugs.  Weekly use the vacuum attachment and run the hose where the baseboards meet the rug.

Follow the instructions to get rid of these spiders fast best defense against these shy yet dangerous spiders is a good offense.  Keeping the house de-cluttered and tightly sealed and getting your home inspected by experts will help ward off these pests and prevent their painful bite.