Can Spiders Drink Milk?
WouterMany people mistakenly think that spiders eat insects. In fact, they suck in juices and blood. But they also drink water from the ground, vegetation, or dew on webs.
The only arachnid known to produce milk is a southeast Asian jumping spider. Researchers recently discovered that it produces milk for its young. Its milk is nutritious and has four times the protein of cow’s milk. Previously, it had been thought that it was produced by other non-mammals, such as cockroaches and earwigs.
In the Chinese Academy of Sciences’ study published in Science, researchers noticed that the spiders nursing their offspring produced a milk-like fluid. This fluid looked similar to human milk, but had four times the protein and fat.
Unlike mammals, invertebrates do not have specialized glands for producing milk, which is why they are believed to produce it from their own bodies. However, they do have sensory systems, small brains, and nerve cells that connect to their muscles. These organs are connected to the central nervous system, which is composed of two simple ganglia.
Several studies have shown that newly hatched spiderlings depend on milk for their first 20 days of life. Similarly, some invertebrates regurgitate food for their offspring. Animals also offer their offspring a variety of other provisions, such as unfertilized eggs.
While these findings are important, they have limitations. For example, it is unknown whether the substance in spider milk contains bacteria or immune chemicals. And it is not known how long the mother continues to feed her offspring this fluid.
