In order to escape from being alone, the male red-back spider chooses to commit suicide

Once upon a time, there was a German who went on a business trip to Australia. One day, he saw a "huge" spider on the construction site. "It was so big that it looked like it was about to draw its sword to duel with you." He was very scared and asked his local colleagues: "Is this spider poisonous? If you are bitten by it, will it be serious?" The Australian colleagues laughed at him in a friendly manner and comforted him: "Don't be afraid, this kind of spider... If you are really bitten by it, we will still drive you to the hospital, but you don't have to drive so fast."

Although it is impossible to determine what kind of spider the German saw, the redback spider can definitely be ruled out - because the redback spider is the kind that requires the car to drive very fast. If the German went to the famous Senckenberg Naturmuseum in Frankfurt, he might be shocked, because there are many spider specimens in the museum, including the type specimen of the redback spider.

Female redback spider | Laurence Grayson / Wikimedia Commons

The redback spider (Latrodectus hasselti) may sound a little unfamiliar, but it is also called the Australian black widow spider, which means it is very similar to the black widow spider (L. mactans) that is mainly distributed in North America.

In 1870, Swedish arachnologist Tamerlan Thorell described them based on specimens collected in central Queensland and named them Latrodectus hasselti. Latro means "robber" and dectes means "biting thing". The specific epithet hasselti was named after his colleague, the Dutch toxicologist and naturalist AWM van Hasselt. Thorell also named a female specimen with a completely black abdomen collected from Cape York in northeastern Queensland L. scelio, which means "villain" in Latin. It can be seen that Thorell thought they were not good people. But later, this specimen was considered to belong to the same species as the redback spider. These specimens are now preserved in the Swedish National Museum of Natural History.

Male redback spider | KKPCW / Wikimedia Commons

The redback spider is very easy to recognize. As a member of the family Theridiidae, it looks like a black "8" with a small head and a large belly. It has eight long legs, of which the first pair of legs is the longest. Adult females are about 10 mm long, with bright red stripes on their backs and hourglass-shaped red or orange patches on their abdomens. Occasionally, individuals with black bodies or incomplete patches of color may appear. Females have white spots or stripes on their bodies when they are young. Males are smaller, usually around 3 to 4 mm, and retain the body color of their "adolescent" period.

Calendar Girl's Tips

The male redback spider can be said to be the most hardworking father in the world. In order to gain a longer time for fertilization, the male spider will actively attract the female to eat him. He puts himself to the female spider's mouth, and while she concentrates on eating, he strives to inject more sperm. The organ that the male spider uses to inject sperm is a pair of fang-like pedipalps on the side of his mouth. After mating, the male redback spider will also cut off the pedipalps in the female's body to prevent her from having sex with other males.

Mating redback spiders. The male inserts the embolus into the female's epigynum and then lifts his body up into a handstand-like position | Lyn Forster / Records of the Western Australian Museum Supplement (1995)

After mating, females can store sperm and use it in the next two years, laying several egg sacs, each containing about 250 eggs. The average age of sexual maturity for females is about 4 months, and for smaller males it is generally around 90 days; females can live up to 2 to 3 years, while males can only live 6 to 7 months. Many males are eaten by females after mating, which is the origin of the name "black widow", but more males do not live to mate.

During copulation, the male spider somersaults into the female's mouth | Lyn Forster / Records of the Western Australian Museum Supplement (1995)

Redback spiders are mainly nocturnal. Females weave webs at night. The shapes of the webs are irregular but very strong. Males and spider babies often live on the edge of the female spiders' webs and steal leftover food. Redback spiders rarely leave their webs, so people will only be bitten when part of their body enters the range of the spider web directly. In addition, the small size and small jaws of redback spiders make them only able to bite people ineffectively in many cases, and males cannot pose a threat to humans. However, if you are really bitten, you still have to deal with it as soon as possible, such as trying to drive faster on the way to the hospital. Since the anti-venom serum has been available, there has been no death caused by redback spider bites.

Redback spider and lizard killed by its poison | Calistemon / Wikimedia Commons

However, not all "redback spiders" are small. At the beginning of last year, our "Sky Eye" (FAST) discovered a special "redback spider" pulsar binary system in the globular cluster M92: its most important feature is that the companion star matter is being accreted by the pulsar. This "redback spider" is 26,000 light-years away from us.

Author: Brooke

Source: Species Calendar