‘Mexican caviar’ is facing big threats. Some are trying to save the ancient delicacy.

CHIMALHUACAN, Mexico — In a shallow lake on the outskirts of Mexico City, a handful of farmers still harvest the eggs of an evasive, fingertip-size water bug in a bid to keep alive a culinary tradition dating at least to the Aztec empire.

Caviar is typically associated with sturgeon in the Caspian Sea. What’s known as Mexican caviar is made from the tiny eggs of an aquatic insect of the corixidae family, also known as the “bird fly” because birds like to eat it.

The bug, which only occasionally surfaces before diving again amid a trail of bubbles, wouldn’t look like food to most people. But it once was important to the people of the Valley of Mexico.

Fernando Llano / AP

Fernando Llano / AP

Fernando Llano / AP

For Juan Hernández, a farmer from San Cristóbal Nezquipayac, cultivating and collecting the tiny insect eggs known as ahuautle — meaning water amaranth in Nahua -— is a way of life.

“For me, more than anything, it means tradition,” said Hernández, 59, who is one of only six people known to still harvest ahuautle in the Texcoco area.

The painstaking collection of Mexican caviar, known for its intense but delicate flavor, is threatened by the drying out of Lake Texcoco, development around the lakeshore and waning interest in the ingredient among younger generations, said Jorge Ocampo, agrarian history coordinator at the Center for Economic, Social and Technological Research on Agribusiness and World Agriculture in Mexico State.

Ocampo calls the dish’s survival an example of “community resistance,” similar to the way in which inhabitants around Lake Texcoco — a shallow, saline lake that once covered most of the eastern half of the Mexico City valley — have managed to preserve other traditions, festivals and ceremonies.

Hernández said it’s hard, dirty work that few are willing to do anymore.

To find the delicacy, he dons rubber boots and wades through the calf-high waters of Nabor Carrillo — a smallish lake formed from the remnants of Texcoco — to collect pine branches he had poked into the muddy lakebed the week before.

The branches serve as an anchor for the bird-fly bugs to deposit their eggs.

Under a blazing sun and accompanied by the calls of hundreds of herons, plovers and other migratory birds that stop at the lakes, Hernández gathers dozens of egg-coated sticks and lays them on a raft of styrofoam.

“We look for them along the edges of the lake, where the flies are more active,” Hernández said.

He started as a young man, after a period of joblessness, joining about four dozen other local residents who used to work the lakes during the ahuautle season — the rainy period from June through September.

After about two hours, Hernández has gathered a heap of sticks covered with thousands of bird-fly eggs.

He returns to the edge of the lake to lay the sticks out to dry in the sun, which can take several hours or days, depending on the weather.

“Cleaning is a process that takes a lot of work,” Hernández said, rubbing his hand over the sticks to remove the eggs and then placing them on acloth.

Later, he takes the eggs home and runs them through a sieve to remove any bits of pine bark or mud. Then. he packs them in bags he offers for sale.

Fernando Llano / AP

Fernando Llano / AP

Fernando Llano / AP

While Hernández takes care of collecting the eggs, Gustavo Guerrero serves them at his restaurant in the east-side borough of Iztapalapa.

One of Guerrero’s favorite recipes is to mix the ahuautle with breadcrumbs and bind them with eggs to form a croquette, which he fries and serves with tomatillo sauce, nopal cactus and squash blossoms — all pre-Hispanic ingredients.

“Eating this is like revisiting the past,” said Guerrero, 61, who says the flavor of the ahuautle reminds him of his childhood, when his mother cooked the dish according to a recipe she learned from her grandmother.

But Guerrero knows that Mexican caviar is at risk of disappearing because younger generations aren’t familiar with the dish, and ever-fewer people harvest it in the scarce remaining lakes where it is found.

Ahuautle also is at risk of becoming only a gourmet dish for the rich: The eggs can sell for the equivalent of roughly $25 a pound.

Farfán has been studying bird flies since 2016. He even has a tattoo of one.

Farfán said indigenous peoples living around the lakes adopted the insect eggs as a source of protein because, prior to the Spanish conquest of 1521, they had few domesticated animals or livestock.

Now, Farfán said, the dish “is associated with the countryside, perhaps with poverty, as if it were an undesirable protein.”

Even those still familiar with ahuautle often consider the insects that produce it to be feed for chickens or turkeys and might think of it literally as “for the birds.”

“There are a lot of kids, young people who don’t eat it anymore, they don’t like it,” Hernández said. “Now, we are just keeping ahuautle alive. I hope it doesn’t disappear because it is a source in income for those of us who live off the land.”

Fernando Llano / AP