A bee that waits all year for one shrub to bloom has finally been given a name

Research by Silas Bossert (Washington State University) and colleagues. Published in the Journal of Melittology, 2026.

Jack Neff collected the bee decades ago. He knew it was something unfamiliar - a small, solitary mining bee, less than an inch long, found in the dry brushlands of southwest Texas. It did not match any known species in the vast genus Andrena, which contains some 1,800 described species and ranks among the largest animal genera on Earth. But without genetic data, Neff could not determine where the mystery bee fit in the family tree. So it sat in a collection, unnamed, waiting for the technology to catch up.

It finally has. Working with Neff and colleagues in Texas and Kansas, Silas Bossert, an assistant professor of entomology at Washington State University, has formally described and named the bee: Andrena cenizophila. The species name translates to "lover of cenizo," and it captures the most striking thing about this insect - it appears to depend entirely on a single plant for food.

One bee, one shrub, one week of blooming

Cenizo, also known as Texas purple sage or Texas Ranger (Leucophyllum frutescens), is the official state shrub of Texas. It grows across the arid southwestern part of the state and into the Mexican state of Coahuila. After a good rain, cenizo erupts into a mass bloom of purple flowers that lasts roughly a week. These blooms can occur multiple times a year, but the peak happens in late spring.

Every pollen grain found on collected specimens of A. cenizophila came from cenizo. No other pollen source was detected. If this holds up with further sampling, the bee is what entomologists call an oligolege - a species that depends on a single plant genus or family for pollen. But the relationship here may be even narrower than typical oligolecty. The researchers found no evidence that the bee visits anything else at all.

This raises an immediate question that Bossert himself posed: what does the bee do for the rest of the year? Cenizo's blooming window is brief - a week or so per rain event. The bee needs to collect enough pollen during that window to provision its brood cells, where larvae will develop underground. Between blooms, the adults presumably wait, though their behavior during these intervals has never been observed.

DNA from three legs and a place on the family tree

Classifying a new species in a genus as enormous as Andrena requires both morphological and molecular evidence. Bossert extracted DNA from three legs of a female specimen - a delicate operation when working with an insect smaller than a fingernail - and sequenced its genome. The genetic data, combined with detailed analysis of body structures including antennae, body shape, and the male reproductive organ, placed A. cenizophila closest to a mining bee from central Mexico.

This makes biogeographic sense. Southwest Texas and central Mexico share arid scrubland habitat, and cenizo's range spans both regions. The two related species likely diverged from a common ancestor adapted to the dry landscapes of the Chihuahuan Desert region.

Bossert, a bee systematist, studies how bee species are related to each other - work he describes as taxonomic housekeeping. Getting evolutionary relationships right matters because the names scientists assign to organisms should reflect their actual history. A misplaced species can distort conclusions about how traits evolve, how biodiversity is distributed, and how conservation resources should be allocated.

Paratypes in Pullman and the Smithsonian

Two paratypes - representative specimens cited in the original species description - will be housed at WSU's M.T. James Entomological Collection, a museum of more than three million arthropods. Additional specimens will go to the Smithsonian Institution. These reference specimens serve a practical function: if another researcher collects a similar-looking bee in the future, they can compare it against the paratypes to determine whether it is the same species or something new.

This matters more than it might seem. With roughly 200 new bee species described worldwide each year, the backlog of unidentified specimens in museum collections is substantial. Many species go unnamed for decades, as A. cenizophila did, simply because no one with the right expertise and tools has examined them yet.

What we still do not know

No one has found an A. cenizophila nest. Mining bees excavate burrows in soil where they construct brood cells, provision them with pollen and nectar, and lay their eggs. The architecture and depth of these nests, the number of brood cells per burrow, and the developmental timeline of the larvae all remain unknown for this species.

The degree of pollen specialization needs confirmation from larger sample sizes. The specimens examined so far carried only cenizo pollen, but the total number of specimens analyzed is small. It is possible that the bee visits other flowers occasionally, particularly during periods when cenizo is not blooming. Finding supplementary food sources - or confirming that none exist - would significantly clarify the bee's ecology and vulnerability.

The species' conservation status is unknown. Cenizo is widespread and not currently threatened, which is good news for a bee that depends on it. But habitat conversion - clearing brush for agriculture or development - could fragment the plant's distribution and leave bee populations stranded in areas too small to support viable colonies. Climate change could also alter rainfall patterns that trigger cenizo blooms, potentially disrupting the timing synchronization between plant and pollinator.

The geographic range of A. cenizophila itself is only roughly defined: southwest Texas and Coahuila. Systematic surveys across cenizo's full range could reveal whether the bee is more widespread than current records suggest or whether it occupies only a fraction of the available habitat.

A reminder of what sits uncatalogued

The description of A. cenizophila is a small contribution to a large ongoing project: cataloguing Earth's bee diversity before habitat loss outpaces discovery. The roughly 20,000 known bee species almost certainly represent a fraction of the true total. Many undescribed species, like this one, are already sitting in museum drawers. Others have never been collected.

For a group of animals that pollinates a significant fraction of the world's flowering plants and food crops, we know remarkably little about many individual species - their host plant preferences, nesting biology, population sizes, and responses to environmental change. Each newly described species is one more data point in a picture that remains frustratingly incomplete.