If you see a millipede on the road, should you drive it away?

Review expert: Ancient Mingdi Lian (He Lin)

Zhihu famous science blogger on mollusks

When it comes to "millipede", you may not be familiar with it. After all, the pronunciation in our lives should be more commonly "malu". But when it comes to its other familiar name - millipede, I believe everyone will be familiar with it.

Today, let’s take a closer look at this insect with legs full of legs.

Source: pexels

Does it really have a thousand legs?

Millipedes are a class of animals belonging to the class Diplopoda of the phylum Arthropoda . In English, they are called "millipedes", where "ped" means "foot". Therefore, millipedes are called "millipedes" in both Chinese and English. However, it should be noted that the "thousand" here does not mean that they really have thousands of feet, but because people see that millipedes have many feet, they use an exaggerated method to call them.

Millipede Source: Pexels

The saying that "millipedes don't really have a thousand legs" has always been a little bit of knowledge when it comes to popularizing these strange animals. However, in 2021, scientists discovered a new species of millipede , Eumilipes persephone, 15-60 meters underground in eastern Australia. It is a veritable "true millipede" with more than 1,000 legs (the largest one has 1,306 legs)! The name millipede finally lives up to its name.

True Millipede

Source: News Photo

Segment after segment, the more segments, the more legs.

At first glance, the body of the millipede is made up of many segments connected together. The first four segments are the cephalothorax, the first segment of the head is called the scolex, and the last segment is called the anal segment. There are no legs on the scolex and anal segments, and the 2nd to 4th segments have only one pair of legs. Apart from this, most of the remaining segments have two pairs of legs each.

So do millipedes have so many legs when they are born?

This is a millipede with scientific name Illacme plenipes. The one in the picture has 618 legs. Source: Wikipedia. Actually, that's not the case. Young millipedes do not have so many pairs of legs when they are just hatched. But as the saying goes, "a sparrow may be small, but it has all the organs." Although they are much smaller than adult millipedes and have far fewer body segments, their body structure is almost the same as that of adult millipedes.

Throughout their lives, they will continue to undergo a developmental process called "segmental metamorphosis". As the name suggests, each time the millipede molts, the number of body segments increases. Therefore, as they molt and grow, the number of legs will naturally increase.

Millipedes' defenses

Since millipedes have so many legs, does it mean that they will run away quickly when they encounter natural enemies?

Although millipedes have many legs, they have a hard exoskeleton on their body surface, which makes them move very slowly and inflexibly . This is not a big problem for millipedes that usually live under fallen leaves, branches and stones and feed on humus, but how to escape from natural enemies has become a big problem that millipedes need to face.

A species of millipede that lives in India

Source: Wikipedia

Fortunately, millipedes have little meat and taste bad, so not many animals feed on them. Some millipedes, such as the spherical millipedes, have evolved a special curling ability . Their first segment is the largest, and the last segment is thicker than the previous segments. If they really encounter an enemy, the spherical millipede will curl up into a ball with the tail and head connected, so that the hard exoskeleton faces the enemy, thus better protecting the relatively fragile abdomen. Millipedes other than the spherical millipedes will curl up into a spiral shape, which can also play a certain protective role.

Millipede curled up into a ball

Source: pexels

In addition, most millipedes also emit toxic or foul-smelling defensive fluids through the scent glands on the sides of their body segments to repel predators . If you try to catch a millipede with your hands, these fluids may irritate your skin or stain your clothes. Therefore, most birds and animals are not interested in millipedes, but meerkats will treat them as food.

Millipede's life habits

Millipedes like dark and humid environments. Most of them live on the surface of lawn soil or in soil cracks, as well as in rotten vegetation and wood. They generally hide during the day and come out at night.

Most millipedes feed on fallen leaves, decaying vegetation, dead wood, and similar foods , using their symbiotic gut microbes to help them break down and digest plant cellulose, but not all millipedes feed on dead vegetation; some also eat the tissues of dead animals.

Around human settlements, millipedes hide under fallen leaves, lawns, and compost . When the air is humid, we can also find them under flower pots and piles of debris. If there is a heavy rain in the fall, you may see a large number of millipedes in your garden at the same time!

Brick-red millipede (Trigoniulus corallinus)

Source: Wikipedia

In rare cases, millipedes may feed on living plant tissue—mostly roots and tubers—and as such, they can become pests in some areas.

They may harm the young shoots and tender roots of plants. In addition to the most common lawns, flower plants such as crabapple and asparagus fern are also victims. Sometimes they even harm crops.

But are millipedes completely useless to humans?

Tiny millipedes have great value

As early as in the "Shennong Bencao Jing", it was recorded that the broad-tarsal millipede can be used as a traditional Chinese medicine, "with the effect of removing poisonous carbuncle and eliminating skin redness and swelling." At the same time, in recent years, professional institutions have conducted in-depth research on the toxicity and pharmacological properties of the broad-tarsal millipede and found that its pharmacological effects are mainly manifested in the following two aspects:

Antibacterial effect: The "Longmalusu Antibacterial Agent" extracted directly from millipedes has a very good antibacterial effect, especially when its concentration is very high, it can even kill some bacteria. However, this antibacterial agent has more of an inhibitory effect when facing most bacteria. When the "Longmalusu Antibacterial Agent" is used together with "penicillin", the efficacy will be enhanced.

Effects on the cardiovascular system: The distillate obtained by distilling millipedes can raise blood pressure in a short period of time. The "worm ketone" further separated from the distillate has the same effect as the substance obtained by distillation, but the "worm amine" phosphate separated at the same time can achieve the effect of lowering blood pressure. During the experiment, it was observed that the combination of worm ketone and worm amine can better regulate blood vessel function.

In addition to humans, some animals also use them. In the forests of Central and South America, there is a kind of monkey that has a special liking for millipedes. Do monkeys like to eat millipedes? In fact, not really, they are attracted by the body fluids secreted by millipedes.

There are countless blood-sucking mosquitoes in the warm and humid rainforest. In order to avoid being bitten by mosquitoes, the monkeys who are annoyed by them will find a millipede and use the foul-smelling liquid (containing benzoquinone chemicals) secreted by it to smear their hair all over their bodies to resist mosquito attacks. The effect is very significant. In addition, some lemurs will also use the defensive liquid secreted by millipedes to smear their bodies to remove parasites.

I didn't expect that monkeys would also use the medicinal effects of millipedes. This makes us marvel at the biodiversity of nature and be impressed by the wisdom of animals. Perhaps in the future, we can find more substances with different medicinal effects from millipedes, so that they can better benefit mankind.