With the uncertain onset of the rains and increasing temperatures many small creatures are becoming active. Many predatory species are taking advantage of the increase in insect life. Compared to previous years, recent reports from the lowveld appear to indicate any more encounters with centipedes.
We have experienced a number of the large green ones with yellow legs - probably of the genus Scolopendra. One recently fell from the thatched roof in a very subdued condition. The creature had no visible injuries but was obviously ‘on its last legs' - probably after an encounter with a large gecko or some other venomous opponent.
Centipedes are normally very agile, with a tenacious grip, and it is very difficult to examine their undersides. In its dazed condition, I had a good opportunity to inspect this one. Many folk believe that centipedes ‘sting' with the modified, pincer-type legs at the tail-end of their bodies.
They can grip firmly with these terminal legs but they ‘bite' with the modified, jaw-like legs under the head. They can inflict a painful bite to humans. Each leg is tipped with a sharp claw. The ‘spiracles', through which they breath, are clearly visible on each alternate segment. These spiracles do not close so the creature can drown if immersed in water for any length of time.
Large centipedes are powerful enough to overpower small frogs and lizards but are, themselves, preyed on by birds such as hornbills and rollers. One of their main predators is the diminutive, normally burrowing, centipede-eater (snake), of which there are four species in the sub-region.
The most common one found in this area is the black-headed Cape centipedeeater (Aparallactus capensis) which has a venom which is very effective on centipedes but harmless to humans. I repeat, for interest, what I wrote in January this year as some folk may have missed the information.
The name means ‘hundred legs'. There are around 3000 species in the class Chilopoda, which is divided into four different orders. Some species do have up to 177 pairs of short legs but the centipedes most familiar to us belong to the order Scolopendromorpha, which have 21 to 23 pairs of legs - less than half the number their name infers. Centipedes are voracious carnivores, preying on insects, snails and worms, with the largest ones (up to 33cm) able to overpower lizards, frogs and small rodents.
Prey is sensed by the antennae, grabbed with the legs and then stunned using the ‘maxillipeds', which are a modified, pincer-like pair of legs behind the head. The maxillipeds have sharp, piercing points with a hollow duct leading to a venom gland.
They eat with their jaws. Some species have venom that can be extremely painful to humans, although normally of the intensity of a bee sting. There are no verified reports of human deaths from centipede bites. In the event of disturbance they can produce defensive secretions or toxins in their spiny legs, each from ‘repugnatorial glands'.
This may be the cause of inflamed marks on the skin reported by people who have had a centipede walking over them. These secondary infections from centipede claws should be cleaned with disinfectant. Centipedes are extremely useful to farmers and horticulturalists for their destruction of crop pests. Remember that, like humans, the greatest harm comes from the mouthparts - in our case, our tongues!