They really can dance on the head of a pin

Among the samples collected by the Falkland Island Invertebrates Conservation Project are the first recordings in the Islands of a minute species of 'fairy fly' only 0.7mm in length. With the smallest species reaching only 0.3mm in length'fairy flies' can be smaller than some single celled organisms and are among the smallest of all insects. Yet, as you can see from the photographs, they are fully functioning winged organisms.

Small enough to dance on a pin head, a Falklands fairy fly next to a pin (shaft diameter is 0.6mm) - Photo: A G Jones

Fairy flies are, in fact, not flies at all, but wasps belonging to the family Mymaridae. The minute wings of these wasps are little more than 'feathered' straps that one might expect to be of little use in flight. However, thin-feathered wings are a common adaptation for flight in the tiniest aviators, the wings unique structure preventing air flow separation and thus preventing the insect from'stalling'.

A fairy flies wings are 'feathered' - Photo: A G Jones

The small size of these wasps affords them with opportunities to exploit resources unavailable to larger animals. Among these the fairy flies have discovered a microscopic, yet nutrient rich, environment in which to raise their young; the eggs of other insects! There are over 1300 known species of fairy fly in the world, all of which are egg parasites, most species favouring the eggs of homopteran bugs, barklice (Psocoptera) or beetles (Coleoptera). The egg host for the Falklands fairy fly is as yet unknown. One intriguing possibility is that the wasps are parasitizing the eggs of dytiscid water beetles. Where this happens elsewhere in the world, fairy fly species are known to use their tiny wings to swim underwater searching for eggs to parasitise.