MINDBLOWING BUGS
Published in the June 6, 2026 edition.
If you’ve been to Mono Lake in the summer, you’ve seen swarms of alkali flies. Maybe you stepped toward them and watched them scatter into shifting clouds, or maybe you noticed them lined up along the shore in dense black bands.
Either way, you haven’t seen them the way Steve Root has. Root is a researcher of alkali flies for the Mono Lake Committee, and on Tuesday night at the Sierra Nevada Aquatic Research Laboratory, he shared surprising facts (and some uncomfortably close-up photographs, see below) of these tiny insects.
Beyond their small size and staggering numbers, alkali flies are an indicator species for Mono Lake’s ecosystem and are uniquely adapted to its extreme conditions.
It’s not an easy place to live. In increasingly saline waters, alkali flies are among the few organisms that can survive in the terminal basin of Mono Lake.
To understand why, you have to look at their life cycle. On average, adult flies live only about twelve days.
Before that, they spend two days as eggs, about three weeks as larvae (across three stages), and roughly two weeks as pupae before emerging as adults.
They spend most of their two- to three-month life cycle in the lake’s dense, alkaline waters. That survival depends on two key adaptations.
First, they have a built-in filtration system. An organ called the Malpighian tubules, also described as a “lime gland, ”filters excess calcium carbonate and salt. The compound is stored in the body and later excreted when pupating, contributing in small amounts to the formation of Mono Lake’s famous tufa towers.
Second, they are effectively waterproof. As larvae, they are protected by a waxy cuticle that prevents water from penetrating their bodies. As adults, they trap a thin layer of air around themselves, known as a plastron, allowing them to walk underwater while remaining completely dry.
“It never gets wet,” Root explained. “Water never touches the body of an adult alkali fly.”
If that isn’t remarkable enough, there’s one more adaptation. And it’s pretty, well, mindblowing.
Look closely at an alkali fly and you’ll notice a crack running across its head. The feature is no accident.
Alkali flies belong to a group of insects known as Schizophora. During emergence from the pupal stage, they temporarily inflate a balloon-like structure in their heads using insect blood pressure. The structure pushes open the pupal cap, allowing the fly to escape. Once the insect emerges, the balloon retracts, leaving behind a visible scar.
But alkali flies are more than just biological curiosities. They sit near the base of Mono Lake’s food web, making them essential to the entire ecosystem.
The flies are one of the lake’s dominant invertebrates and serve as a critical food source for migratory and nesting birds, which consume them by the thousands.
They have also long been an important food source for the Kootzaduka’a people, who traditionally harvest and eat the flies’ pupae; a practice that continues today.
Because so many species depend on alkali flies, changes to their population can ripple throughout the ecosystem.
And fly abundance is closely tied to lake salinity. Research has shown that as salinity increases, alkali flies become smaller and less abundant.
Higher lake levels dilute the lake’s salt concentration, creating better conditions for the flies and the many species that depend on them.
For those working to restore Mono Lake, that makes alkali flies yet another reason why higher lake levels matter.
