In this article you will be able to check varied information about the black widow spider, its curiosities and characteristics . See also photos this arachnid, how it breeds and necessary care to avoid accidents. Follow!
Spiders, as well as harvestmen, scorpions, mites and ticks belong to the phylum of Arthropods and the class of Arachnids . Spiders have a wide geographical distribution, with about 36 thousand species described all over the Earth, with the exception of Antarctica and the Arctic.
These invertebrates occupy both the terrestrial and aquatic environment. Most human beings have a certain fear of spiders, as they are poisonous and some also have toxins in their hair. However, there are species from the Uloboridae and Holoarchaeidae families that do not produce poison.
They can live in webs, natural holes in the soil, crevices in ravines, trees, shrubs, under rotten trunks, termite mounds, bromeliads, etc. They also live in human houses, in warehouses, garages and in various man-made buildings. The spiders that build webs depend exclusively on them, as their vision is very limited. The moment the prey touches the spider’s web, vibrations are produced and captured through sensory hair. Spider species respond to different stimuli and have different attack patterns.
Curiosities about the black widow spider
Black widow spiders can be found throughout Brazilian territory. The popular name “black widow” is due to the fact that many females are in the habit of devouring the male after copulation . After copulation, the female lays eggs in a cocoon where dozens of chicks can be born. The female has a black abdomen, with reddish designs or a greenish or grayish body with orange spots. They feed on small insects that get caught in its web.
Spiders belong to the class of arachnids (Photo: depositphotos)
Black widows can be found in small shrubs in webs constructed in an irregular way. They live in warm temperate climates and are usually not aggressive. These animals have a preference for old tires, empty cans and shoes. They are poisonous spiders and they bite when they feel threatened . Its poison has neurotoxic action, that is, the toxin reaches and damages the victim’s nervous system.
Most of the accidents caused by the black widow occur in the hot and rainy months (between March and May). Commonly, the lower, upper limbs and the dorsal region are the most affected. An orifice may be observed at the site of the bite, followed by redness, swelling and sweat. The stinging pain is intense , like a pin penetrating the skin with burning sensations.
In more severe cases, intense muscle pain may occur two to three hours after the bite, an acceleration of the heartbeat, followed by a decrease in the heartbeat, weakness, tremors, a feeling of death, arrhythmias and changes in the levels of calcium and potassium.
Spiders have genital openings in the ventral part of the reproductive organs, in both male and female. In females, there are two openings that serve to fit the plungers (male reproductive organs).
Despite not being aggressive, this spider bites when threatened (Photo: depositphotos)
During the reproductive season, the male weaves a web and ejaculates a portion of semen. Now, he is ready to search for the female and mate. Upon meeting the female, he will perform the famous “mating dance” . Through movements, sensations and vibrations in the web, the female will recognize the male so that both identify and then copulate.
During the copulation process, some exhaled substances called pheromones assist in the identification between male and female. After copulation, fertilization takes place with the laying of eggs. The eggs are stored in a silk thread pouch and their number varies.
Importance of spiders
Spiders, in general, are of great importance for maintaining the dynamics of ecosystems . Like the black widow, most of these animals are carnivores, feeding mainly on insects and other invertebrates that are trapped by the webs.
Some are also actively pursuing their prey. Spiders, which weave their webs, depend directly on them to feed and perceive the environment around them. When the prey is captured by the web, the spiders inject their venom and bandage them in silk threads to immobilize them.
The black widow traps its prey in the webs it produces (Photo: depositphotos)
After bandaging, the action of saliva on the prey together with the poison, digests the tissues of the predated animal, transforming them into a broth. This broth is sucked and taken to the spider’s stomach, where digestion is completed. Some species abandon trapping prey and steal prey from other webs. The main predators of spiders are frogs, birds and geckos .
The human being is also considered a great enemy for spiders. Many technologies and uses of pesticides have destroyed the natural habitat of these animals, thus interfering in ecological relationships.
See also: Arachnology
Accidents with black widow
The main types of poisonous accidents are scorpions, snakes and spiders, with 39.72%, 30.21% and 19.77%, respectively. In Brazil, there are approximately 20 species of spiders, included in three genera, that can cause poisonings in humans: Latrodectus (black widow), Loxosceles (brown spider) and Phoneutria (spider weasel).
Poisoning by Latrodectus (black widow) causes severe pain, muscle contractions, changes in heartbeat and violent abdominal cramps. Correct treatment depends on the rapid and accurate diagnosis of the arachnid involved and the adoption of appropriate therapeutic measures. Among these, the administration of specific serum stands out , mainly in accidents with brown spider and black widow.
The black widow is black in color with only one red detail on the body (Photo: depositphotos)
When the individual is bitten by the black widow we call latrodectism. The first report of black widow accidents in Brazil was made in 1948 in the state of Rio de Janeiro. As time went by, new cases emerged, being in the 60’s in the cities of Rio de Janeiro and Niterói and more recently in the city of Agudos in São Paulo and in some states of the Northeast. Black widow accidents have been reported more frequently in the Northeast (BA, CE, RN and SE).
The venom of this spider acts on the sensitive nerve endings and on the autonomic nervous system by releasing neurotransmitters. Treatment is carried out through serotherapy with antilatrodectus serum.