Native Stingless bees with pollen pants

These bees sure are busy!

They appear to be nesting inside an old plastic fountain. I’ve also seen them nest in walls, cracked concrete, really anywhere that’s good for them.

The bees are also carrying big balls of pollen. Because of the position of the pollen on their legs, it looks like they’re wearing puffy pants ❤

Unidentified, Tribe Meliponini

(images: x x x x x)

"The tribe Euglossini, in the subfamily Apinae, commonly known as orchid bees or euglossine bees, are the only group of corbiculate bees whose non-parasitic members do not all possess eusocial behavior."

Wikipedia

"The perfume that male orchid bees create by collecting scents from the flowers they visit is designed to make females choose them rather than another mate.

Male orchid bees collect raw materials from multiple sources, including the orchid flowers they pollinate. These are used to concoct perfume mixtures that are stored in specialised hind-leg pouches (...)."

"The composite odour created by combining different molecules allows communication of more integrated information, such as how suitable a male is to be a father (...)."

A single gene for scent reception separates two species of orchid bees

Orchid bees are master perfumers, and research suggests that the perfumes males concoct are unique to their specific species. For years, Ramirez, a member of the UC Davis Center for Population Biology, and recent Ph.D. graduate student Philipp Brand, Population Biology Graduate Group, have studied orchid bee mating behaviors, unraveling the complex chemicals responsible for successful procreation. The research has given them an unprecedented view into the formation of new species. And the driver of divergence: environmental perfumes.

In a study appearing in Nature Communications, Brand, Ramirez and their colleagues link the evolution of sexual signaling in orchid bees to a gene that's been shaped by each species' perfume preferences.

"Our study supports the hypothesis that in the orchid bee perfume communication system, the male perfume chemistry and the female preference for the perfume chemistry can simultaneously evolve via changes in a single receptor gene," said Brand, whose thesis was the basis for the study.

"Imagine you have an ancestral species that uses certain compounds to communicate with each other," said Ramirez. "If you have a chemical communication channel and then that chemical communication channel splits into two separate channels, then you have the opportunity for the formation of two separate species."

Of the 250 orchid bee species, Brand's and Ramirez's research focused on Euglossa viridissima and Euglossa dilemma, two separate species previously classified under a single scientific name. They diverged roughly 150,000 years ago. Physically and genetically, these two species are almost indistinguishable, but luckily, they primarily live in non-overlapping ranges in Central America and South America, with some overlap in Mexico's Yucatán Peninsula.

"This is a neat distribution for the study of species formation because it reveals that the variation we observed is not just the product of geographic variation, and when the two species coexist, they still remain as separate species, even though they experienced hybridization in the recent past," said Ramirez. "Each species is occupying a unique niche in chemical space."

E. viridissima and E. dilemma are actually easier to tell apart by the chemical differences of their perfumes. Using gas chromatography and mass spectrometry, the researchers separated and analyzed each chemical compound in a male orchid bee's enticing perfume. Between the perfumes of E. viridissima and E. dilemma, the difference came down to two molecules. E. viridissima's perfume contains a molecule called 2-hydroxy-6-nona-1,3-dienylbenzaldehyde (HNDB), and E. dilemma's contains a lactone called L97.

"We found the bees grouped into two clouds based on the presence of these major compounds, which strongly suggest that each of these corresponds to a separate species of orchid bee," said Ramirez.

According to Ramirez, this means that these pheromone-like perfumes aren't just different between the species but that they likely influenced their original divergence.