Jumping Spider Suckles Spiderlings As if they were a litter of kittens

Researchers have discovered that jumping spiders ( Toxeus magnus an ant mimic) fed their young with a substance resembling the ant milk. (Credit: Chen / Science)

Do you have milk? Of course, you do it; few things are as mammals as our milky childhoods. Of course, we all have spine (just like lizards), warm blood (birds too) and hair (plants too) – but it is the mammary glands from which mothers badfeed their offspring that set us apart really mammals from the rest of the Tree of Life.

That's why it was a bit shocking when the researchers announced today that another species was providing milk to its youngsters. The last born of the milk-producing family … is a spider.

Suckling Spiderlings

This of course depends on the general definition you give to "milk". In some restrictive definitions, milk refers explicitly to the secreted liquid nutrient. by mammals to feed their young. Ask the dairy industry and she is a firm believer that this definition is the only one acceptable – and has even tried to sue the companies that, in her view, use the term abusively. But throughout history, the word "milk" usually refers to a number of milk-like substances, including coconut milk, almond milk, and some plant juices. There is no general consensus on the definition of "milk".

There are already some non-mammals known to feed their young substances that their bodies produce. Doves and pigeons, for example, produce "harvest milk," a very nutritious substance, but not particularly similar to milk, that parents regurgitate for their young. Flamingos and some penguins also secrete a similar substance in their esophagus. There is even a badroach species that gives birth to live young people after feeding them "milk" inside the mother's hatch – a substance that has been declared one of the "most nutritious substances in the world." Earth".

But these substances are quite far from milk and, although these parents give them to their children, they certainly do not feed in the most literal sense of the term. That's why it's so dramatic to see the image of a spider, surrounded by his little head, like a dog with a new litter of puppies. Yes, this image exists. You asked for it:

Spiders several days old gather around their mother. On the right, spiders older than 20 days absorb a milky substance directly into their mother's epigastric furrow. This is the first recorded case of a non-mammal with behavior that is so closely related to the milk supply. (Credit: Chen / Science)

Spider Mother's Milk

Researchers from the Chinese Academy of Sciences discovered this object while responding to an observation concerning Toxeus magnus a species Jumping spider mimicking ants. Spiders are usually solitary, but scientists have noticed that groups hang out in nests, including groups of an adult female and several youngsters.

They suspected that there was still a lot to learn about the interactions between these nests. Why did not these spiders scatter, unless staying together has no advantage?

To find out, the team, led by researcher Zhanqi Chen, studied spiders in a laboratory located at Xishuangbanna Tropical Botanical Garden in Yunnan. After the hatching of new baby spiders, the scientists observed whether the spiders would leave the nest for food and whether the spider mother would bring food to the nest. They did not do it. This lasted 20 days and while the spiders grew and developed normally.

A closer look reveals the extraordinary: Immediately after the hatching of spiders, the spider mother deposited droplets of a nutrient into the nest. the babies ate with the droplets.

Then, after the first week, the spiders pbaded suckling milk directly from the spider mother . This continued even after the spiders had left the nest for their first hunt, completing their nutrition until the age of about 40 days.

The milk is secreted by the epigastric groove of the spider, a spot located on the underside of the abdomen where the dog or cat bad might be.

Spider's milk is the most mammalian at the moment

If you're not yet rude enough, the researchers were able to get a spider, under a microscope, to secrete a few drops of milk. after slight pressure of the fingers on the abdomen. "They of course badyzed the liquid and discovered that it contained sugar, fat and about four times more protein than cow's milk."

Finally, to be really sure to see what's going on. they thought they saw, they did a number of tests on spiders At different times of the spider's development, they either closed the mother's epigastric furrow to block access to the milk (by covering it with correction fluid ), removed the mother completely from the nest, which allowed them to see how much the spiders depended on the milk itself and what care the mother lavished on the milk.

Blocking milk or removing the mother after 20 days, when the spiders were old enough to leave the nest, was detrimental but not devastating for young spiders, but preventing newly hatched spiders from feeding resulted in 100% mortality. u their mother's milk to live, just like little humans.