Centipedes And Millipedes

Centipedes are invertebrates and appear worldwide in around 3,000 different kinds and cover a wide span of habitats, from the tropical rainforests to deserts, although they need a dump surrounding to live in. In daytime they are usually hidden under stones, thick layers of leaves or other rotting plant materials. At nightime they come out and start hunting for prey.

Centipede in the Rainforest

A centipede in the Malaysian jungle of Pangkor Island. That's their typical milieu - rotten plants on the ground. Image by Asienreisender, 2009

A centipede's size varies between 1cm and 25cm in the tropes (scolopendra are the tropical kinds), although most of them are rather small and don't extend a length of 10cm. Despite their name most centipedes have less than a hundred legs - they vary between 15, 21 and 23 pairs of legs up to 191. They all have an odd number of leg pairs, for they grow in a pattern of four legs (two pairs), while the front pair is then altering into the pair of stings or claws. The centipedes eyes have a lense and are better than those of many other insects who have only facete eyes.

They get often mixed up with millipedes, but are much more seldom. Their physical shape is also differing from the millipedes, who are more compact and equipped with more but shorter and thinner legs. Moreover, centipedes are mostly carnivorous and equipped with a pair of venomous claws or stings. The bulk of their food are earthworms; additionally they eat small insects. The very big centipedes can even eat small rodents and mammals.

Some time after I piled up some of these stones below the window of my study, I found a smaller centipede in the guest bed. Checking the stones outside, there was a nest inside the bottom one. Tiny, white hatchlings crawled inside. The round shell is the skin of a passion fruit. Images and photocomposition by Asienreisender, Kampot, 10/2016

Centipedes can move very quick and are extraordinarily aggressive. They overcome prey with a high speed, catch it with their legs, bite and kill with their poisonous pair of stings. Their poison is strong and contributes to their aggressivity; when disturbed, the centipedes often not withdraw, but attack. They do attack also humans, and a sting of them is, although not lethal, but extremely painful for several days. The poison is a mixture of different, harmful chemicals as hydrocyanic acid, histamin, acetylcholin, serotonin and others. Allergic reactions can happen.

The poisonous stings of scolopendra are flexible and can be moved in all directions. Being touched at the rear the animal can turn round most quickly and attacks directly. They can also errect two thirds of their body length.

When being bitten, the wound swells and the strong pain can affect the whole body. Sometimes paralysing effects appear over days, sickness, dizziness and a deaf feeling around the bite is coming with the sting. Fever might appear. Medical treatment can be necessary, painkillers can bring relief. For a healthy human there is still no live danger to expect; nevertheless, a bite affects the health severely for several days; besides there are two lethal cases documented.

It's possible to have a secondary accident due to a bite, for example when being bitten on a stairway and falling down due to the sudden pain.

These guys are better to avoid. However, they appear far not as often as the harmless millipedes. Besides, they vary often at least in colour. Images and photocomposition by Asienreisender, Kampot, 2015

Centipedes are themselves the natural prey of birds, some lizards like tokay geckos, snakes, some spiders, mice and rats and some other animals. Humans don't like them and usually kill them when possible. I have seen a local man hunting a centipede at Lake Toba; he was very eager to make sure to get the beast killed. Reportedly they have the scary habit to come swiftly out of the dark and rush towards peoples feet.

These insects need a moisture microhabitate, for they loose quickly water. On the other hand they can not swim. Fallen into a bucket of water, a centipede will drown.

The evolutionary track of centipedes leads back 430 million years. They have been among the first animals living on land, after live left the oceans. In fact they look very 'old fashion', in evolutionary terms.

Curiously, some kinds of centipedes are 'matriphagic', means that the offspring is eating it's mother after reaching a certain size.

While the centipede above are all of smaller size (around 5cm), this one is a large, mature one above 20cm long and at least a centimeter in diameter. A cat drove him out of his hideout towards my kitchen door. Image by Asienreisender, Kampot, 6/2015

The family of millipedes contains around 10,000 different kinds, probably many, many more. They appear all over the world, except in the antarctica. Their preferred habitats are forest floors with rotting leaves, dead wood and humid soil.

None of the millipede's kinds have a thousand legs; they never exceed a few hundreds. Their size is varying between millimeters and 35cm as the biggest. These animals have a bad sight, are only able to distinguish between bright and dark. For that they are equipped with a cluster of simple, flat-lensed ocelly at both sides of their head. Some kinds who specialized in living in caves lost their sight completely.

Millipede

The first two images show a millipede feeding from food remains on a road in Chiang Khong. The image below left shows one in the patch of tropical rainforest left near Pangandaran on Java. The brighter one bottom right lived on Kiririom Mountain in Cambodia. Images by Asienreisender, 2011, 2012

In difference to the carnivorous centipedes, the millipedes feed from rotten plant materials and other decomposing stuff like human or animal food remains. They also feed on faeces. A few kinds can feed also on living plants, and exceptionally they can become a plague.

On the other side are the millipedes themselves preyed upon by many different animals as birds, lizards, snakes, mammals and other insects. When getting attacked, the millipedes roll themselves in defense, saving their vulnerable legs inside. They are, due to their short legs, slow, have no stings and are not able to bite. Nevertheless, some tropical kinds of the species produce a secretion which can cause skin irritation, itching, blisters or little pain.

Millipedes have two sexes and are highly reproductive. A female lays up to 300 eggs per time. Some species build a nest for the offspring, and some care a time for the eggs and the small ones after hatching. Their live expectation extends up to ten years.

This one is one of the two biggest millipedes I got to see. He appeared one afternoon, at the peak of rainy season, in my garden at the foot of Bokor Mountain. Length about 25cm to 30cm. Images and photocomposition by Asienreisender, Kampot, 10/2016

When millipedes appear in great numbers they can become a pest, particularly when intruding human housings or feeding from crops.

The fossil record of millipedes lasts back to long ago times of evolution. They are as well as the centipedes among the first animals who lived on land. One in the family of the millipedes, arthropleura, was the largest known invertebrate in evolution, reaching a length of 2,60m. That was about 330 million years ago.