World’s Tiniest Known Insect

The world’s tiniest insects are male fairy wasps (also known as chalcid wasps). Four males, lined up-end-to-end, would be about the width of a period in this post. The females are considerably larger (Wikipedia, 2026).

Fairy wasps are therefore dimorphic (two main kinds): the males are blind, have no wings (Fig. 1) (therefore cannot fly), and are much smaller than the females (Fig. 2), which have compound eyes and wings. They females literally “swim” through the air. This is because they are so small that the air is comparatively dense. Thus, they do not fly, in the sense that you think. The viscous effects of air on a wing increase at smaller sizes. Thus, an insect 1 mm or smaller moves through the air as a bumblebee would move through mineral oil! In sum, the air is not thin for fairy wasps, rather it is a very thick, syrupy fluid. Furthermore, female fairy wasps need fringed wings and specialized wing motions in order to navigate highly viscous environments.

The antennae of male fairy wasps are thread-like, whereas those of females are tipped by club-like segments. The adult life span for fairy wasps is only a few days. They are parasitoids of the eggs of other insects, thus, they lay their eggs in other insects and then eat the host egg!

Fairy wasps have been around since mid-Cretaceous time (Albian), about 105 million years ago), and their fossilized remains are found in amber deposits. 

Today, there are 1,400 known species of these chalcid wasps, and they can be found living today in temperate, subtropical, and tropical areas throughout the world. 

   Classification

Kingdom Animalia

Phylum Arthropoda

Clade (1 of them)

Class Insecta

Order Hymenoptera

Family Mymaridae

Genus Dicopomorpha [note: some scientists use Mymar, as the type genus]. 

Type Species D. echmepterysis

Figure 1. Male-fairy wasp: Dicopomorpha echmepterysis, [or Mymar of some researchers]. 

Figure 2. Female-fairy wasp: Dicopomorpha echmepeterysis, [or = in genus Mymar of some researchers]. 

References

Wikipedia, 2026

Sklar, J. 2024. Just a Li’l Bit. The world’s tiniest insect fights off crop pests and inspires more efficient computers. Sierra Magazine, Spring 2024, pp. 65-67.