Both spiders are venomous, but the black widow has a reputation for being more dangerous to humans, while the brown widow, which is usually much more aggressive, has venom that causes mild symptoms such as mild irritation. .
Researcher groups reported through journals Annals of the Entomological Society of Americaof a conflict between black widow and black widow spiders that would jeopardize the survival of one of these species in the United States.
To pinpoint the possible cause of the decline in the population of one of these species, scientists pitted different species of spiders to see what might be the reason.
Black widow numbers are declining compared to brown widows in America
southern black widow (Latrodectus mactans), known for its dark color and red abdomen, has disappeared from southern Florida in recent decades, researchers report.
on the contrary, brown widow (Latrodectus geometry) is an African species that was discovered in the United States in 1990 and is more regularly observed in the same area.
Both spiders are poisonous, but black widow Instead, it has a reputation for being more dangerous to humans. brown widow which are usually much more aggressive, but have venom that causes mild symptoms such as mild irritation.
Who wins when two spiders face each other?
Black vs Brown Widow: Spider Fight
Scientists believe that population decline is black widow It was due to the final struggle for territory and food. However, experts brown widow hunts black widow .
To test this theory, experts at the University of California, Riverside conducted an experiment in the lab.
Brown widows were placed against other spider species such as house red (Nesticodes rufipes), triangular (Steatoda triangulosa), or black widows.
The study authors brown widow Black widows were 6.6 times more likely to kill, regardless of sex, size, or developmental stage. An unusual phenomenon because both arachnid species are closely related.
Unlike other species that interacted with brown widow acted very aggressively black widow more daring and quickly attacked the youth.
Improved playability
Lead author Luis Coticchio said, “Brown widow’s behavior is highly aggressive towards Southern Black widows, but much more tolerant towards other spiders of the same family.” proved.
of brown widow “They ended with them (black widow ) before they react. They are very opportunistic,” said study co-author Richard Vetter.
But Black Widow was also able to defend herself. “There were cases when a defending Black Widow was able to trap an aggressive Brown-her Widow in a spider web and inject venom into it,” the scientist observed.
Another factor identified by the researchers was that female black widows were smaller than brown widows and laid only one egg compared to brown widows who laid multiple eggs simultaneously.
Source: Biobiochile
