Before you begin to think I’ve completely lost it, let me explain. A far cry from the magical, mischievous creatures of folklore, the Fairyfly is actually a type of parasitic wasp. Although they might not have much success against Tinkerbell in a beauty contest they are fascinating insects with a life cycle more akin to a horror film than a fairy tale…
Fairyflies are a family of parasitoid wasps which include the smallest known species of insects; and they really are ridiculously small, ranging from a mere 0.2mm in length to a maximum just under 2mm. Whilst working as a research assistant at the Natural History Museum, Mymarids were by far my favourite parasitoids to work with because, despite the difficulties associated with their size, they are unbelievably striking. They look very unlike the other members of the Chalicidoids, the group of parasitic wasps to which they belong, as they have narrow fringed wings, which are thought to help them effectively “swim” through the air.
Fairyflies are probably one of the nicer characters found among the parasitoid wasps as they only parasitise the eggs of their hosts. Other, more gruesome relatives of the fairies have a life cycle that has been likened to the film Alien. The famous, disturbing sequence of cinema picturing the emergence of an alien being out of a human chest is a terrifying reality in the insect world.
Parasitoids feed and develop during their larval stage in the body of their insect host: literally consuming them from the inside out and inevitably resulting in the death of the host. The fully-grown insect parasitoid then emerges from its host ready to face the seemingly impossible task of tracking down a new victim in which to lay its own eggs. These parasitoids that develop inside the body of their host are called endoparasitoids, however there are various other types.
This paints a rather sinister picture of these insects but luckily for us they are blessed with a dual personality. As a result of their proficiency as insect-hunters they are employed in agriculture as an effective method of bio-control. They are often very particular about the species they select and so can be used to track down and kill pests without affecting non-target insects. Fairyflies have been successfully used for this purpose on a number of occasions, the best example being Anaphes nitens, which has been applied across southern Europe, South Africa, New Zealand and South America. This particular parasitoid species is recruited to protect eucalyptus plants, cultivated for paper production, from weevils; perhaps acting more like guardian angels rather than fairies for these trees.
Therefore not only are parasitoids a fascinating product of evolution, so bizarre as to warrant Hollywood fame, they are also pest-busters of little acclaim, carrying out an environmentally friendly crop protection service.
Image from: http://www.nhm.ac.uk/research-curation/research/projects/chalcidoids/mymaridae.html