This post is also available in: Dutch.
I’ve been stung, in between my forefinger and middle finger, and I have done nothing to deserve that. At the time of the event my first reaction was a good flick in the direction of what dared to stab me in my own house. Only after having treated the painful area with a cloth soaked in vinegar for five minutes, after which the pain decreased significantly, I went looking for the culprit. I already had an idea of what it could have been. Already for months there is considerable activity around the house. Even against vertical walls large nests are built. The animals responsible for this frantic action are an important asset to nature, they pollinate flowers, they ensure that caterpillars do not take the upper hand, and they construct their nests with a geometrical precision to which a mathematician will take of his hat. It should be clear to everyone by now that I am talking about paper wasps (Polistes versicolor), or as we call them locally: maribomba. Especially in the rainy season, the amount of wasps increases astronomically on the island. That’s no coincidence, because the animals depend on water for their ingenious nesting behavior, and to provide offspring.
Hexagonal paper nests
If you take an up close look at a paper wasp nest, once it is no longer in use, of course, you’ll quickly observe the amazing symmetry. The nest consists of a collection of hexagonal ‘rooms’, hence with six sides, which are fixed together so ingeniously that one begins where the other ends. There is no empty space to be found in the nest. The nests are made of a paper-like material that the animals produce themselves. The animals chew up wood pulp and mix this with saliva to create the building material. Before the chambers are being built, however, an adequate nest site needs to be selected. This can be a ceiling, against a vertical wall, the branch of a plant or under a window frame, a location that ensures that the nest is not affected by wind or rain. First, a thin stalk is constructed to which the nest will be attached. This stalk is very important for the nest, because the wasps will treat it with a chemical substance to fend off predators. A kind of security system against ants and other crawlers that would like to snack on the larvae in the nest. This stuff is regularly refreshed. At the end of the stalk the first rooms are attached. The first rooms are round in shape, and extension to multiple rooms will result in the characteristic hexagonal shape.
A colony of women
A maribomba colony can start in two ways. An individual female can start a nest, but research has shown that individualists are often not very successful, ninety percent of the nests will not survive. The main reason for the failure of these nests is in general that the female prematurely abandons the nest in search of a colony to join. Successful nests are those that are run by a colony, several females together, that build and maintain the nest and care for the young together, and protect the nest against threats. The colony does not necessarily consist of only sisters or other relatives, it is not uncommon for ‘strangers’ to join. However, there is always a dominant female in the nest. Sometimes fights will break out among the females. A battle for the dominant position. If the dominant female dies, another will take her place.
Larvae and pupae
Eggs are laid within the rooms, one egg in each room. When the larva hatches from the egg, the females take care of it jointly. The larvae eat insects, and are constantly hungry. It is a coming and going of wasps that are looking caterpillars, flies, mosquitoes, beetles and other insects. Moreover, not all the reproductive activities occur simultaneously. In most cases there are different life stages found in the nest. One room houses an egg, the next one a larva which has just hatched, next to a full grown larva ready to pupate. Another room houses a pupa next to a room from which a brand new addition to the paper wasp population liberates itself. As the larvae grow, the edges of the rooms are raised. When it is time to pupate, the hole at the top is closed with silk, after which the larva is transformed into the next generation of wasps.
I did not notice the animal that attacked me. It landed on my arm and because I carelessly touched it without looking, she felt so threatened that she did sting me. Normally it is quite obvious that a maribomba is not something to mess around with. In nature, the bright yellow and black patterns on the body of these animals signify only one thing: Hands off!
And I did not. It’s not just the paper wasps that fly around with alarm messages. Bees are another type of animal you’d better keep away from. The difference is that a bee will die after stinging, and a paper wasp does not. It will live on to sting again, if needed. Man has cleverly exploited this color pattern to implement the various warning signs that point out things not to do or not to touch. The sign in the illustration that warns of radioactive radiation speaks volumes.