Generales

By Natalia Piedrahita Tamayo, Journalist at UdeA Communications Office 

The angelitas—stingless bees known for their communal behavior—are among the most common winged species on the Universidad de Antioquia’s Medellín campus. These bees often build their nests in human-built structures such as concrete walls, asphalt surfaces, bricks, and wood. To better understand their presence, the Environmental Academic Corporation led a project to catalog the stingless bee species found throughout University City. 

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Stingless bees, particularly Tetragonisca angustula, thrive in urban settings and often nest in small cavities found in buildings. Photo: Communications Department / Alejandra Uribe Fernández. 

As you stroll through campus, you may have noticed a nest of stingless bees tucked into a wall or hidden among the trees. These “little angels,” known scientifically as Tetragonisca angustula, thrive in a variety of spots—gardens, roofs, walls, pigeonholes, statues, and along campus paths. Their nests range from tiny to quite large, but each one holds ecological importance. Inside, the bees build a complex social world, producing and storing honey while helping sustain the biodiversity around them. 

In 2024, the project “Characterization of Native Stingless Bees at University City” identified 301 nests across the campus. The Allies with the Planet group from the Environmental Academic Corporation presented their findings to the Division of Physical Infrastructure. Alejandro Jaramillo Vélez, a group member, shared that they divided the campus into 15 sections and trained 20 volunteers selected through an open call to survey each area. The group brought together students from law, microbiology, environmental engineering, and animal husbandry, as well as members of the GAEA Research Group, focused on beekeeping and agricultural insect studies at the Faculty of Agricultural Sciences. Using the GAIA app, the team mapped each nest’s location and gathered detailed data on factors like surface type, height, orientation, and vulnerability of the nests and their entrances. They documented the nests with photos and uploaded all information to the KOBOTOOLBOX platform for thorough analysis. 

Many nests face serious risks—people have blocked their entrances with garbage or even set them on fire. “These nests are fragile; they can easily be knocked over, stepped on, or kicked. Our plan involves relocating them to advanced hives designed specifically for stingless bees and placing them in carefully chosen gardens. However, this is just one part of a broader conservation effort. Environmental education remains essential to raise awareness about the urgent need to protect pollinators and to encourage a respectful, harmonious coexistence with these vital creatures,” said Edwin Mora Aristizábal, environmental engineer and project leader. 

The survey of stingless bees showed that most nests appear within the physical structures of campus buildings, on the ground, or statues, while only a few grow in trees. The University Museum and Blocks 12 and 13 have around 30 nests in total. Additionally, the team located 89 nests on the mesh surrounding the university and its adjacent green space near the ring road. Map: courtesy. 

The Meliponine tribe includes social bees from the corbiculate Hymenoptera group—the corbicula being the pollen basket they use to gather pollen. These bees have lost the ability to sting, making their stings nonfunctional. Colombia is home to nearly 120 species of Meliponine bees, which inhabit all thermal zones. They are small, usually ranging from 7 millimeters to 2 centimeters in size, and feed exclusively on pollen,” explained Mora Aristizábal. 

Photo: Communications Office/ Alejandra Uribe Fernández. 

The project’s data reveal that nearly 38% of the nests lie more than one meter above the ground, putting them at risk from pedestrian traffic. Maintenance work by the institution and debris—such as hair and trash—gathering on stair risers also threaten the nests. 

Researchers found that only 10% of the nests display defensive behaviors, like circling or biting when approached. Because of their mild aggression, the university community needs to learn how to coexist peacefully with these bees. Promoting respectful actions and minimizing unnecessary contact can help protect and preserve their well-being. 

The entrances stand out as the most notable part of these nests, acting as gateways or antechambers leading to vast honeycombs, where bees build cells based on their social roles. Out of all the entrances found on campus, only three showed no bee activity. Currently, some technologically advanced hives exist within university offices, protected voluntarily by their residents. This project aims to officially integrate these hives into the Universidad de Antioquia’s campus landscape. 

“Technologically advanced hives provide the space and comfort necessary for conserving stingless bees and harvesting their honey. In meliponiculture—the practice of breeding these bees—the most common hive designs are the INPA and AF boxes, which feature compartments that enable honey extraction without disrupting or damaging the nest. Despite this, many keepers still raise angelitas in traditional homes like clay pots, bamboo logs, and rustic boxes,” said David Duque, environmental engineer, and project researcher. 

Pollinator preservation as an environmental education exercise:  

Nest Entrance or Pollinator’s Threshold. Photos: Communications Office / Alejandra Uribe Fernández. 

Besides the stingless bees known as “angelitas” (Tetragonisca angustula), other native species—Nanotrigona sp., Scaptotrigona sp., and Partamona sp.—also inhabit the University’s Central Campus, highlighting the significant bee diversity in this area. 

“Colombia stands out as one of the countries with the highest diversity of stingless bees. Their ability to thrive in urban settings offers a valuable advantage, as they support pollination within cities and help preserve plant genetic diversity despite the continuous loss of natural habitats. In tropical areas like ours, maintaining ecological balance depends largely on pollination by bees such as these, which explains the implementation of several conservation programs,” said Alejandro Ruiz, biologist and researcher at the Faculty of Exact and Natural Sciences. 

The expert explained that, like honey bees (Apis mellifera), angel bees exhibit a complex social structure known as eusociality. It means they organize into distinct roles—workers with specialized tasks, drones, and queens. Morphologically, they stand out with reduced wing veins, smooth, hairless eyes, and a diminished stinger. Their nest-building techniques involve the use of materials such as wax and clay, reflecting their unique biology. 

Pollination reaches beyond bees, positioning them as umbrella species that also safeguard other pollinators such as beetles and flies. Although these insects are less noticeable than bees, they play a crucial role in pollination. Protecting a single group often preserves entire ecosystems and their complex networks, supports forest health, and promotes meliponiculture—the agricultural practice focused on producing honey-based products for food, medicinal, and cosmetic uses. 

“Millions of insects depend on pollination, and plants rely on it to bear fruit. Expanding our view reveals that pollination underpins human nutrition. Protecting pollinators—whose biggest global threat comes from pesticides—is vital for the well-being of our planet,” Ruiz stated. 

Allies with the Planet Group 

Since its founding in 2008, the group has consistently focused on studying bees and other pollinators. Following the pandemic, they intensified efforts to monitor nests—particularly those of stingless bees—responding to ongoing reports of potential risks to the university community. This experience highlighted the urgent need to educate residents of University City, Medellín Campus, about the bees’ behaviors and to establish measures that protect the most vulnerable nests.