Chinese scientists have discovered a kind of spiders that can produce milk and take care of their young, a new vision on the understanding of the maternal care of invertebrate animals.
The study, published in Science, focuses on Toxeus Magnus, a species of jumping spider native to Southeast Asia that lives in nests and resembles ants.
According to the study, sand found that spider mothers in their laboratory nests feed their young with a substance similar to milk and continue caring for them as they mature.
During the first 20 days, it was found that the spider babies first drank droplets of spider milk that remained on the surface of the nest and Then they sucked directly from the area of his mother's abdomen. Compared to cow's milk, spider milk has almost four times the protein but less fat and sugar.
From day 20 to day 40, the young spiders were able to leave the nest to hunt food, but they were still allowed to drink milk from their mothers.
The most intriguing part begins after 40 days when Spiders reach sexual maturity. Only daughters were allowed to stay with their mother in the nest, while the females attacked the children and they were not allowed to return home.
In the study, maternal care and milk supply seemed to work together to ensure the long-term survival of young spiders.
Of the 187 spiders observed in 19 different nests, the survival rate was 76 percent for the spiders that received both. Separated from the mother on day 20, the survival rate of the spiders was reduced to 50 percent.
Previous studies show that maternal care, which continues after the offspring reaches maturity, only exists among some advanced long-lived social vertebrates, such as humans and elephants.
Chen Zhanqi, lead author of the study of the Xishuangbanna Tropical Botanical Garden, told Xinhua – quoted by the Chinese Academy of Sciences – that the findings show that the provision and parental care of mammals for sexually mature offspring also evolved in invertebrates.
He noted that the new findings encourage researchers to reevaluate this "breeding style" among animals, especially in invertebrates. Invertebrates make up more than 95 percent of the Earth's species.
Nicole Royle, lead professor in behavioral ecology at the University of Exeter in Britain, said it is the most comprehensive study proving that long-term maternal care also exists in invertebrates.
"It will help researchers better understand the process of evolution of milk supply and parental care for sexually mature offspring throughout the animal kingdom," he said.