How do Jumping Spider mothers feed their young?

How does a jumping spider mother feed her babies?

Researchers in China reported in the journal Science in 2018 that the jumping spider Toxeus magnus, found in tropical and subtropical Asia, feeds its young a milk-like fluid. The mother produces it from a crease on her abdomen called the epigastric furrow.

How the feeding works

• For roughly the first week after hatching, she leaves droplets of milk around the nest for the spiderlings to drink.
• Later, the young press against her body and drink straight from her.
• Spiderlings feed only on milk for their first 20 days.
• After that they begin hunting on their own but keep nursing for almost three more weeks, about 40 days in all.

What is in the milk?

The milk is high in protein. Per milliliter, researchers reported about 2 mg of sugar, 5 mg of fat and 124 mg of protein, which is about four times the protein of cow’s milk.

Why the milk matters

In the experiment, when the milk furrow was sealed at hatching, all the spiderlings died within about 10 days. When it was sealed at day 20, survival dropped significantly, so milk still mattered after the young began to hunt. With milk and their own hunting, 76 percent of lab-raised young survived to adulthood.

Is it the same for all jumping spiders?

No. This was shown in one species. As far as is known, most spiders do not feed their young milk, and common house jumping spiders are not known to do this. Some spider mothers do not care for their young at all.

Can people see it?

It happens inside the nest and is easy to miss. Do not open nests; the mother defends her young.