The diversity of stingless bee species reflects the different diets and resources required to maintain healthy hives. In the process of collecting food and nesting materials, stingless bees are responsible for pollinating our biomes and generating fruits and seeds for wildlife.

Author:  Ana Paula Cipriano

Leia em Português

The basics of a diet involve consuming daily sources of protein, carbohydrates, and vitamins, which is also true for social bees. The main source of protein for both stingless bees and honeybees, for example, is pollen. The amount of protein and vitamins in each pollen source depends on the plant visited. Therefore, collecting a diversity of pollen types can enhance the development and health of bees. This is one of the reasons why bees need an environment with many plant species: to ensure they have high-quality nutrients from pollen grains.

However, pollen is not the only source of protein for bees. With more than 550 species, stingless bees have diversified habits. While pollen is the most important protein source for bees, some species also collect protein from dead animals. For example, the “mombuca-carniceira” (Trigona hypogea) in Brazil is common in several areas from Acre to São Paulo, and foragers of this species can be seen consuming dead animals instead of carrying pollen.

Interestingly, bees use brush-like structures on their legs to organise pollen pellets in a specific area called the corbicula, allowing them to transport this resource to the nest. In bee species that obtain protein from dead animals, the corbicula may be smaller, as they do not need it to carry pollen.

Carbohydrates are also an essential resource for diets in general. Stingless bees get most of their sugar from visiting plants and usually store this resource in the nest in the form of honey. Some plants offer nectars with different percentages of sugar. In general, stingless bees prefer to collect nectar with a higher concentration of sugar, but it also varies according to the species. Alternatively, foragers can collect sugar from fruit juice and plant sap. These resources provide food when the availability of flowers is not abundant.

Other materials are also important for stingless bees, either as building material or for colony protection. For instance, foragers collect plant resins as a substance for hive protection, with antimicrobial activity. Even though some bees prefer specific plant groups to obtain resin, they can collect this material from several plants, resulting in a diversity of resins with distinct chemical compositions and microbial defence. Trigona bees, for example, may stimulate plants to produce these sticky materials by biting their tissues, an interesting behaviour, as it induces the plant to produce a reward for them. Mud is also a material that can be useful for stingless bees. Melipona bees are usually seen carrying mud to the hive, where it is used as a building material.

An ecologically important and beautiful behaviour is seed transport by stingless bees. Animals that disperse seeds perform an essential role in the environment, as these seeds will grow into new plants distributed across the landscape. Australian stingless bees have been observed collecting resin from seeds and transporting thousands of them. After collecting the resin, they may discard the seeds close to their nests, which later grow into trees in the surrounding area.

Lastly, to obtain all these resources, foragers go on daily trips to find everything they need. Depending on the hive’s needs, bees decide whether to collect sugar or protein. Most foragers are specialists in collecting specific resources like pollen or nectar, as they are often more efficient than generalist foragers. Even in the case of generalists, they may organize their resource collection by time, visiting plants to collect pollen in the first hours of the day and nectar later on.

Stingless bees are fantastic insects that not only produce delicious honey but also pollinate our native plants, act as decomposers of small animals, and disperse seeds.  The more we study the hundreds of species of Meliponini bees, the more we discover interesting behaviours. Therefore, protecting our biomes is essential to maintaining the health of our native pollinators by offering all the resources they need to survive.

References

#3 – Mombuca come carne – A.B.E.L.H.A. (abelha.org.br)

Grüter, C., 2020. Stingless bees: their behaviour, ecology and evolution. Springer Nature.

The curious relationship between the cadaghi tree and native stingless bees – The Queensland Naturalists’ Club Inc. (qnc.org.au)