Mono's Alkali Fly: The First Fly You'll Ever Love
> about mono lake > natural & human history > ecology: alkali flies

Mono's Alkali Fly
The First Fly You'll Ever Love

You can hold them under water as long as you please--they do not mind it--they are only proud of it. When you let them go, they pop up to the surface as dry as a patent office report, and walk off as unconcernedly as if they had been educated especially with a view to affording instructive entertainment to man in that particular way.

Mark Twain
Roughing It


A walk along Mono's shore stirs up masses of alkali flies.BUZZZZZZZZZ

If you listen closely, this is what you hear at the edge of Mono Lake on calm summer days as swarms of black alkali flies carpet the shoreline. Walk among them and they move away from you, not at all interested in humans. If you were algae in the lake, it would be a different story. Along the shoreline, at the surface, and even beneath the lake, you can watch alkali flies busily feeding on microscopic algae.


Ephydra hians, the alkali fly, is also found at other saline aquatic environments besides Mono Lake.Alkali flies spend two of their three life stages entirely underwater. The larval and pupal life stages develop within the lake. When the adult fly is ready to emerge from the pupa case its head comes apart! The head separates and a small sac inflates and pops the top off the pupa case. The sac then collapses, the fly's head reassembles itself, and the fly emerges from the case to float to the surface where it then begins its adult life cycle. Eventually adult flies return underwater to lay eggs or feed on algae. Tiny hairs trap a thin layer of air which allows the fly to "scuba dive." On calm days in the summer you can watch small, silvery teardrop shapes amble along the bottom of the lake in shallow water.


Brewer's Blackbird feasting on alkali flies.At Mono Lake flies are food. Most birds prefer dining on the flies. Alkali flies provide more fat and protein than the brine shrimp. This is the principal food that Phalaropes use to grow new feathers and then migrate three thousand miles non-stop to South America. In the mid to late summer the Wilson's Phalarope can be seen spinning in shallow water, creating a miniature vortex that brings alkali fly larvae and pupae to the surface for easy pickings. You can also watch California Gulls and Brewer's Blackbirds run along the shoreline with beaks open filling themselves with adult alkali flies.


An old photograph of a Kutzadika'a woman collecting alkali fly pupae at Mono Lake.The alkali fly was an important source of food for the Kutzadika'a people during the summer months. Linguistically related to the Northern Paiute peoples, the Kutzadika'a (pronounced Kootz-a'-di-ka-a') lived part of the year in the Mono Basin hunting and gathering. The pupal stage of the alkali fly was collected in shallow water along the lakeshore. Since the pupae are rich in fat and protein, they were an excellent source of food that were dried and used in stews. The Kutzadika'a even traded this delicacy with neighboring peoples. Kutzadika'a means "fly eater" in the Kutzadika'a native tongue.



The Big Picture

Volcanic History


Lake Chemistry



Alkali Flies

Brine Shrimp

Bird Life

Other Wildlife

Plant Communities


Human History

Kutzadika'a People

Prospectors & Pioneers

Water History