The iconic red hourglass of the black widow spiders (genus Latrodectus) is traditionally considered an aposematic signal, yet experimental evidence is lacking. Here, we present data that suggest that black widow coloration may have evolved to be an aposematic signal that is more conspicuous to their vertebrate predators than to their insect prey. In choice experiments with wild birds, we found ...

Tarantulas have recently become as pets in most parts of the world that increased the probability of encountering emergency physicians with patients hurt with these spiders. Their attacks usually do not cause general manifestation, however there are some case reports in this regard. Here, a 40-year-old man was reported who was referred to the emergency department with severe periumbilical pain ...

Experiments tested the ability of newly emerged spiderlings of a black widow spider, Latrodectus hesperus Chamberlin & Ivie (Araneae: Theridiidae), to crawl through brass screen of various mesh size. The purpose was to determine whether immatures of these medically important spiders could be excluded from buildings. In horizontal orientation, black widow spiderlings were able to easily pass thr...

The phylum Arthropoda includes arachnids and insects. Although their bites typically cause only local reactions, some species are venomous or transmit disease. The two medically important spiders in the United States are widow spiders (Latrodectus), the bite of which causes intense muscle spasms, and the brown recluse (Loxosceles), which may cause skin necrosis. Widow bites usually respond to n...

BACKGROUND This review provides the physician with a clinical approach to the diagnosis and management of spider bites. It examines the recent literature concerning management of bites causing dermonecrosis, secondary infection, neuromuscular damage, and allergic reactions. METHODS Using the key words "spider bites," "brown recluse spider bites," "necrotic arachnidism," "black widow spider bi...

Black widow spiders can cause variable clinical scenarios from local damage to very serious conditions including death. Acute myocardial damage is rarely observed and its prognostic significance is not known. We report a rare case of a 35-year-old man who developed an acute myocarditis with cardiogenic pulmonary edema requiring mechanical ventilation caused by black widow spider's envenomation....