Fairyflies are parasitic wasps that are among the smallest known insects. Huber and Noyes* described a new species of Fairyfly, Tinkerbella nana, from Costa Rica. The tiny wasp was found in sweep net samples of vegetation. Only the adults are known and not much about the biology of the new species is yet known.Huber and Noyes raise an interesting question. Tinkerbella nana has wings and presumably flies. The female is at most 250 microns (0.25 mm) in length. The smallest known flying insects are fairyflies that are about 150 microns. Huber and Noyes argue that 150 microns is about the lower limit for flying insects. Insects smaller than that are expected to have issues with muscle size and strength needed to power the wings. Insects smaller than 150 microns, such as the fairy fly, Dicopomorpha echmepterygis, are wingless.
Some fairyflies not only use their wings for flying but swim with them as well. These fairyflies are egg parasitoids of aquatic beetles and swim to reach oviposition sites.
*Huber J, Noyes J (2013) A new genus and species of fairyfly, Tinkerbella nana (Hymenoptera, Mymaridae), with comments on its sister genus Kikiki, and discussion on small size limits in arthropods. Journal of Hymenoptera Research 32: 17-44.