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Ecology

You Don’t Know a Thing About Bees

Bees are fundamental to the world’s agricultural ecosystems and tropical forests because of the role they play in pollination. Without bees, many plant species would face extinction. Though they are considered essential to the survival of our planet, many bee species are now endangered due to pesticide exposure, poor nutrition, increased parasite transmission, habitat degradation, and reduced genetic diversity. Scientists from the Smithsonian Tropical Research Institute in Panama are studying the ecology, and microbiology of several of the more than 30,000 species of bees in our world; they are founding a wealth of surprising information.

Text and photos: Javier Pinzón

 

In addition to knowing that bees, as pollinators, are the cornerstone of our ecosystem and a key component in our world’s agricultural productivity, I also now know that they sometimes come in sparkling colors, they produce honey, and they perform extraordinary dances to indicate the location of flowers to their companions.

That’s why everything I learned from Dr. David Roubik, a scientist with the Smithsonian Tropical Research Institute (STRI) who has been studying bees for forty years, and Dr. Jordan Kueneman, a postdoc at STRI, confirmed to me that my biology studies and all the National Geographic documentaries I’ve watched in my free time have not made me an expert. The truth is, the world of bees is so diverse and so subtle, with the differences between one species and another so profound, and their balance so delicate, that I suddenly realized I didn’t know a thing about bees.

As I begin the interview, the first thing I notice is that the scientists, who are about to open a bee colony, aren’t wearing any protection. Kueneman explains to me that these Tetragonisca angustula bees, from the Meliponini tribe, have no stingers and are very calm. Not only am I surprised by their small size, but also by their yellow color and their indifference to our presence. When Kueneman and his collaborators open the box and reveal the nest, I discover a miniature city with several structures that immediately remind me of the buildings of Antonio Gaudí, which I saw a few years ago in Barcelona.

The researchers are preparing to take samples from the nest: honey, pollen, resin, larvae, pupae, cell provisions, some adults who care for the nest, and others who leave to get food. The scientists intend to research the microbiology of the bees’ development and their behaviors in their home, so that they can fully understand the complex and highly dynamic nature of the interactions between bees and smaller organisms, both inside and outside the bees’ bodies. For this, they must sequence the microbiomes of fifty-three select species of tropical bees, which they collected every two months for a year. The scientists traveled through the lowland tropical rainforest and the highland cloud forests of  Panama to gather the different types of bees.

Roubik explains that the worker bees build the nests with wax they produce from three pairs of dorsal glands on their abdominal segments, mixed with a pitch they harvest from several plants. The result is called beeswax. The bees then fill individual cells with pollen or nectar. To perform the difficult task of producing honey, bees work together to evaporate the nectar: the goal is to reduce the water content of the nectar from 70% to 20% or 25%. How do they do it? By holding a drop of nectar in their mouth and beating their wings forcefully.

After they finish the sampling, Kueneman and Roubik prepare to move a Scaptotrigona panamensis nest, that was inside the trunk of a fallen tree, into a nest box. This is another stingless bee species; it is also a honey producer, but it is larger and more aggressive. Patiently, with the help of a chainsaw, Roubik begins the delicate work of opening the colony while the others observe. Since the bees lack a stinger, they get tangled up in people’s hair and bite to defend themselves — they are often referred to as hair bees.

Roubik reminds us that the important principles in bee societies of any size are kinship recognition, the division of labor, the assignment of tasks, and feedback from the colonies. A guardian bee is impregnated with the smell of the nest and its inhabitants to enable it recognize and repel intruders.

Advanced social bees living in large colonies (from thousands to tens of thousands of adults) focus intently on knowing their queen. They do this through the use of pheromones: glandular products that carry specific messages and responses in the brain of the insect and the endocrine and nervous systems. Contact pheromones are spread by the queen through her “entourage” of worker assistants; they reach all the areas and individuals in the nest. The labor in bee colonies is divided between the primary breeders and their helpers. Each has a duty so that the colony can survive and reproduce. These honey producing bees have a very special characteristic: they live in a permanent social structure. They only have one queen and she cannot live without the workers, just as they cannot reproduce without her. All are necessary parts of a colony.

Honey producing bees depend on water, flowers, and the resin they find in their flight range: from one to seventy-seven square miles. They use precise, effective communication to produce honey, which they make for the sole purpose of feeding their young; the adult bees feed on pollen.

Stingless bees have a fundamental difference from Mellifera bees (honey bees with stingers): the latter are free swarms. A colony leaves the mother colony, with the queen established at the head, and the nesting site is given to a new queen and a part of the worker population. In contrast, the meliponine bees (stingless bees) require a new nest prepared from scratch, with a well-made entrance and some food stored, before a new, unpaired queen moves in and a part of the worker bees from the mother colony can fly to her. In addition, the distance of the new colony from the mother colony cannot exceed 100 meters (328 feet). In some cases, the mother colony continues to support the daughter colony after separating by allowing worker bees to transport food or building materials from one nest to the other.

When I thought I finally understood that some groups of honey bees have stingers and others don’t, I once again met with the scientists, this time in the STRI labs in Gamboa.

The team, including a master’s student Ernesto Bonadies, is working with another group of bees that are glittery green and gold color with some blue and red tones. In this group of bees, orchid bees of the Euglossini,  the males do not have stingers, but the females do. The researchers attract the males by offering strong scents that the males collect on a specific area of their legs to attract females. They are part of the 92% of bees that are solitary, and some are even parasites of other bees, Kueneman explains. This fact that perplexes me: only 8% of the 30,000 species of bees are social. However, highly social bees, honey bees and stingless bees, dominate bee fauna worldwide.  Roubik goes on to emphasizes that the vast majority of bee species live alone, in small tunnels in the ground, or up in the trees. In these solitary bee species, a female makes a nest, supplies individual breeding cells with pollen and nectar, lays her eggs, and dies. The males only exist to reproduce; they do not care for the nests.

Together, all bees, whether wild solitary species, highly social colonies, or managed species such as honey bees, are essential to agricultural ecosystems and tropical forests around the world due to their role in pollination. Without bees, many species would cease to exist. For example, the Eufriesea concava bee is the only pollinator of the national flower of Panama: The Flower of the Holy Spirit orchid. Indeed, we must conserve intact old growth forests and promote the regeneration of damaged forests to protect bees and the plant species they interact with from extinction. Undoubtedly, humans depend on the services provided by bees and we shouldn’t lose sight of that.