Black widows disappeared from the southern United States due to competition from a closely related species of brown widow. Reported by TASS with reference to the Entomological Society of America.
Black widows are large predatory spiders that have a very venomous bite due to the release of potent neurotoxins. Basically, these animals live in the New World and were most common in the southern United States. Latrodectus mactans And Latrodectus hesperus. In recent years, scientists have noticed that their numbers have decreased significantly. African widows took their place. Latrodectus geometric.
American biologists decided to find out what was the cause of the population decline. Observations have shown that both widows have no problems extracting food – they die much more often from attacks by other predators and large animals than from a lack of nutrients. At the same time, the scientists revealed differences in both the growth rate and size of female spiders, and the response of brown and black widows to rival aggression.
Specifically, the researchers found that African young female brown widows are about 10% larger than black widows of similar age, but reach puberty 16% faster and produce twice as many offspring on average. In addition, biologists have found that female brown widows deliberately attack and kill about 80% of their “competitors” among black widows, but are much less likely to show aggression towards other spider species.
At the same time, experts do not have any explanation for such behavior. To answer this question, it is necessary to examine the relations of brown widows with other species in their homeland, Africa.
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