Black Widow Spiders Active In Spring

by Les Harrison

Spring officially begins March 20, 2018 with the equinox occurring. While the day and night will be equal length at the equator, here in Wakulla County it will take a few more weeks for the daylight to surpass the night’s number of hours.

No matter, the warm weather in February has started the seasonal rush of landscape and yard maintenance chores. Garages, shed, barns and other storage units are being pried open after months of sequestered idleness in search of the necessary implements for the work to come.

What would a job be without tools to ease the accomplishment of every task, and impress the neighbors? The months of temperature enforced disuse make the re-acquaintance almost as good as opening presents on Christmas day.

Unfortunately, other residents of the area may have taken advantage of the extended quiet time and set up a residence in or around the neglected gear. Worse yet, they may take a very dim view of what they perceive as a home invasion.

One reclusive species which is included on this list of presumptuous trespassers is the Southern black widow spider, Latrodectus mactans. It is easily identified by its shiny, totally black body and the characteristically bright red shape on its abdomen or backside.

Southern black widow
Southern black widow
Photo by Les Harrison
Reclusive But Deadly

This venomous spider is found throughout the southeastern United States, including Wakulla County, but it is not the wicked aggressor of urban legends. In reality, this reclusive arachnid prefers isolated sites where it can hunt its prey without potential for human contact.

The southern black widow is one of three members of this genus which can be found locally. The less frequently encountered brown widow and red widow have many of the same behavior features, but with different coloring.

There are 32 species in the Latrodectus, or widow spider, genus which are found on every continent except Antarctica. Most of the females of this genus are dark with the distinguishing hourglass mark.

Widow spiders received their common name from the belief they would kill and consume their mate. However, the practice was mainly observed in laboratory settings under crowded conditions.

In natural settings this behavior is more associated with the male’s physical inability to escape rather than the female’s interest in consuming him. Some insects, including the local praying mantis population, engage in similar behavior.

The bite of the southern black widow spider is toxic to mammals with many potentially damaging or deadly results. The females are equipped with the greatest concentrations of the toxin which is used for hunting and self-defense.

The widow spiders construct a web of irregular, tangled, sticky silken fibers. The spider commonly hangs upside down near the center of its web waiting patiently for insects to blunder in and becomes entangled.

The spider quickly bites a victim then wraps it in silk before the insect can free itself and flee. It uses its fangs to further administer digestive enzymes, liquefying the prey’s internal organs before beginning to feed.

Heavy Gloves Are Recommended

Southern black widows are thought to have poor eyesight and depend on vibrations arriving through their web’s silk strands to find trapped prey or warn them of possible threats. While not especially aggressive, if cornered they will deliver a painful bite to the closest point of contact.

Most injuries to humans are defensive bites delivered when a spider gets unintentionally squeezed or pinched. No matter the circumstances, immediate medical treatment is advised.

Heavy gloves are recommended when working in areas which may be frequented by southern black widows. These included barns, garages and outbuilding which attract insects, and the spiders preying upon them.

Use caution when reactivating landscape equipment in the spring. Spiders can be cranky.


Posted: March 2, 2018

Category: Florida-Friendly Landscaping, Home Landscapes, Pests & Disease
Tags: Les Harrison, Southern Black Widow, Spiders, Spring, UF/IFAS Wakulla, Wakulla Extension

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