black widow spider

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1. an arthropod of the class Arachnida.
spider bite in the United States, the two spiders whose bites are most likely to cause a serious reaction are the black widow spider(Latrodectus mactans) and the brown recluse spider(Loxosceles reclusa). Signs and symptoms are associated with the effects of injection of the venom and include pain at the injection site, weakness, muscle pain and cramps, elevated blood pressure, and restlessness. Bites by these spiders must be treated promptly and effectively. First aid is the same as that for a snakebite and includes the following:

1. Wash the wound with soap and water and apply a clean dressing.

2. Apply a constricting band between the area of the bite and the heart.

3. Keep the person calm and transport him to the hospital or medical facility as soon as possible.

4. If swelling becomes apparent, apply a cold compress to the area.
black widow spider Latrodectus mactans, a poisonous spider found in North America; see spider bite.
brown recluse spider Loxosceles reclusa, a poisonous spider found in North America; see spider bite.
vascular spider a telangiectasis due to dilatation and branching of superficial cutaneous arteries, which presents as a bright red central portion with branching radiations, the whole somewhat resembling the configuration of a spider. The lesions may occur singly or in large numbers, and may be nevoid or acquired, being commonly associated with pregnancy and liver disease. Called also nevus araneus, spider nevus, and spider telangiectasia.

black widow spider

Etymology: AS, blac + widewe; ME, spithre
Latrodectus mactans, a species of spider found in the United States, whose bite causes pain and sometimes death.
enlarge picture
Black widow spider with fresh egg case
A venomous spider indigenous to North America—most bites occur in California, most commonly in summer. The black widow spider measures 13 mm in length with a leg spread of 40 mm; it bites with its anterior fangs and may be fatal in very young children and older adults
Management Supportive—topical cleansing, ice, aspirin, opiate analgesics, hot baths, mild sedation, bed rest; for muscle spasms, calcium gluconate, methocarbamol or phenadrine; for hypertensive crises, short-acting antihypertensives; antivenin-Lyovac may be indicated in some patients

black widow spider

Latrodectus mactans Toxicology A venomous spider indigenous to North America–most bites occur in California, more common in summer–which is 13 mm in length with a leg spread of 40 mm and  which bites with anterior fangs and may be fatal in the very young or old Clinical Abrupt sharp, cramping and/or burning pain, dizziness, weakness, spreading to the entire body, activation of autonomic nervous system–N&V, sweating, salivation, tremors, muscle cramping and spasms, twitching, paresthesias, eyelid edema, ptosis; severe cases are accompanied by SOB, tachypnea, respiratory grunting, tachycardia, systolic HTN, acute nephritis and hemoglobinuria in small children Management Supportive, mild sedation, bed rest; for muscle spasms, calcium gluconate, antihypertensives; antivenin-Lyovac may be indicated in some Pts

black wid·ow spi·der

(blak wid'ō spī'dĕr)
A venomous arachnid, attacks always come from female (Latrodectus mactans); reported throughout the United States, but more common in the South; marked on underside with a white 'hourglass' shape. Only small children and immunocompromised patients are likely to die from her bite, although the acute form of the paralysis can cause severe pain.

black widow spider

see latrodectusmactans.
References in periodicals archive ?
Overwintering juvenile Latrodectus hesperus females from this geographical location tend to begin building their webs in Apr.
Chemical prey cues influence the urban microhabitat preferences of Western black widow spiders, Latrodectus hesperus.
Este mismo comportamiento fue observado en Araneus diadematus (Araneidae) por Gerhardt (1924) y Elgar & Nash (1988), en Latrodectus hesperus (Theridiidae) por Ross & Smith (1979), en Dictyna volucripes (Dictynidae) por Starr (1988), en Achaearaneae jequirituba (Theridiidae) por Gonzalez & Poncio (1992), en Achaearaneae tepidarorium (Theridiidae) por Gonzalez & Armendano (1995) y en Pholcus phalangioides (Pholcidae) por Bartos (1998), y podria ser utilizado con el mismo fin.
Aspects of the courtship behavior of the black widow spider, Latrodectus hesperus (Araneae: Theridiidae), with evidence for the existence of contact sex pheromone.
We have shown that, in Latrodectus hasselti and Latrodectus hesperus juveniles, the palpal tibia is significantly wider in males than in females, and this allows accurate identification of sex using a simple visual examination of the spiderlings.
maculata) Pisauridae Ancylometes bogotensis Merrett (1988) (Keyserling 1877) Pisauridae Pisaurina mira Bruce & Carico (1988) (Walckenaer 1837) Theridiidae Latrodectus hesperus Ross & Smith (1979) Chamberlin & Ivie 1935 Theridiidae Latrodectus Stern & Kullmann (1981) tredecimguttatus (Rossi 1790) Thomisidae Xysticus cristatus Bristowe (1958) (Clerck 1757)
Within Theridiidae, three Latrodectus hesperus Chamberlin & Ivie 1935, fed on old dead insects (Ross 1981), and four individuals of Faiditus sp.