The red widow spider has a reddish-orange head, thorax and legs with a black abdomen. The top of the abdomen usually has a row of red spots with yellow borders. This spider lacks a complete hourglass on the underside of the abdomen and instead usually has one or two small red marks. The egg sac is white and smooth. (Net Ref (1)
It has been found primarily in sand-pine scrub habitats in central and southeast Florida, specifically from Marion County to Martin County.
The red widow constructs its web in palmettos, rosemary, scrub oak, and other shrubs.
The webs of adults are generally located 3' to 10' above the ground, (spiderlings and immatures build their webs close to the ground) and the main area of the web can extend up to 4' from the females retreat. It is basically a cobweb sheet with a large number of snare lines extending upwards. Their prey flies into these snares, and usually falls to the sheet. The widow then rushes out to make the capture.
Adult females of this species specialize in capturing flying insects.
Caution: This spider is venomous and can be harmful to people. The female's venom is a neurotoxin which causes sustained muscle spasm rather than local tissue injury.
Note from J. Hollenbeck:
A clear lymph fluid also oozes from the pores surrounding the bite. The muscle spasms are permanent, (at least my case) reoccurring several times a year for several minutes at a time. The bite was treated as L. mactans, although treatment may have been unnecessary, as spasms, oozing, and localized redness were the only effects of the bite.
Males and immatures do not bite.
For more general information about the Widow spider, please refer to the Latrodectus genus info page.
If you are bitten by a widow spp. spider:
Contact your physician, hospital or poison center immediately and follow their instructions. Poison Centers across the country now have a new national emergency phone number - 1-800-222-1222.
Collect the spider if possible for identification. Your physician may administer an antivenom treatment and calcium gluconate to alleviate pain, and will probably treat the site with antiseptic to prevent infection.
If you have a heart condition or are otherwise vulnerable, you may require a hospital stay until symptoms subside. Usually bite victims recover fully within two to five days.
Be very careful when working around areas where widow spiders may be established. Take proper precautions-wear gloves and pay attention to where you are working. The reaction to a widow bite can be painful, and the victim should go to the doctor immediately for treatment.
3) Venomous Spiders in Florida
: A detailed article by G. B. Edwards, Taxonomic Entomologist, Florida Dept of Agriculture & Consumer Services