Gold leaf acts as surprisingly effective camouflage for insect homes tucked into the corner of Catholic altarpieces—or so restorers working on Panama City’s Catedral Basílica Santa María la Antigua realized after discovering 120 clusters of bee nests accidentally sealed in the church’s central artwork for more than 150 years.

Scientists at the Smithsonian Tropical Research Institute (STRI) helped restorers identify the mysterious structures as 19th-century orchid bee nests. The team’s findings, newly detailed in the Journal of Hymenoptera Research, simultaneously testify to the one-of-a-kind nature of the discovery and offer a window into the region’s centuries-old ecosystem.

The mummified bee nests were trapped in the altarpiece during restoration work conducted in 1875, five years after a devastating fire damaged parts of the cathedral. These repairs, made with a careful eye on the church’s budget, included replacing the brick floor with the cheaper option of concrete and adorning the altarpiece’s columns with gold leaf, paint and glitter. The red, green and gold glitter—a sure sign of the restoration’s subpar quality—has since been removed, journalist, museologist and cathedral chronicler Wendy Tribaldos tells Atlas Obscura’s Sabrina Imbler.

“Our cathedral is quite poor, by cathedral standards,” says Tribaldos. “Before the restoration started, the church had broken windows, so pigeons made their nests inside the cathedral. But there was a resident cat, so at least there were no rodents.”

The most recent restoration was a years-long process completed in time for a visit by Pope Francis, who consecrated the church’s new altar in January 2018. Restorer Sofia Lobo discovered the bee nests, called cells, while cleaning the 20-foot-tall altarpiece, or reredos. During the four months it took to reattach fallen paintings and reapply gold leaf to the mahogany reredos, Lobo noticed that the knobby, hole-ridden structures behind the columns were made of a different material.

“We didn’t even see the cells at the first moment, because it was covered in gold,” Lobo tells Atlas Obscura. “But when we saw the nests from behind, we knew it was something natural, something made from some kind of bug.”

Lobo showed the nests to Tribaldos, who brought them to STRI. There, scientists Bill Wcislo and David Roubik identified the clusters as the nests of female Eufriesea surinamensis bees, a species known for its iridescent face and bright yellow back legs. While males tend to spend their time around orchids, females visit many species of flowers, making it harder to track them down. Their nests, built of bark, mud and resin, are also hard to spot in the wild.

The restorers found not only the nests, but the mummified remains of bees and pupae, as well as pollen grains left in the nests’ cells. After assessing these specimens, STRI researchers realized that the find was essentially an insect-made, golden-sealed time capsule of Panama City’s 19th-century ecosystem. Tropical pollen expert Enrique Moreno identified pollen from 48 plant species, including a kind of tea mangrove that’s now uncommon near the city.

“I was amazed that they found such old nests,” says STRI lab manager and research assistant Paola Galgani-Barraza in a statement, “to have the opportunity to discover the vegetation that these bees collected from in that time and to find a species that is no longer in this area. The pollen comes from different sources—what they were eating, what was trapped in the resin that they used to make their nests and pollen in the wax on the walls of the cells.”

The team’s analysis suggested the pollen originated from a mixture of short, shrub-like plants and mature forest growth. To confirm their findings, the STRI researchers compared the data to photographs of the landscape in 1875. Coincidentally, snapshots taken by 19th-century photographer Eadweard Muybridge, who cataloged Panama City in the late 1800s, decorates the sixth floor of STRI’s headquarters.

Wcislo reached out to Smithsonian American Art Museum specialist Richard Sorensen, who provided an original photo of the city circa 1875. Muybridge’s image captured the same view predicted by the researchers’ pollen evidence: shrubbery with patches of mature forest.

“After confirming which bees made them, Wendy Tribaldos requested the return of the nests,” says Galgani in an email. “It was then that they fell into my hands and, after hearing the history of where they come from, I thought of doing the analysis to see if I could find pollen and come up with a list of species, so we would know if there was any change in the vegetation since that time. This list will serve as a reference for future studies.”

Orchid bees are normally sensitive to changes in their environment, Berry Brosi, an Emory University biologist who wasn’t involved in the study, tells Atlas Obscura. He adds that the study is “interesting in showing that these bees can and did coexist with humans, when the land-use change that humans were causing is not too extreme.”