Stingless bees are a very diverse group of tropical bees, with some species similar in size to a fruit fly and others larger than a honeybee. These native bees have a range of behaviours that they perform daily to ensure that the colony is structured, has enough food, and is safe from predators. But how do these social insects determine who is in charge of each of these behaviours?

Author: Ana Paula Cipriano
Leia em português

Social insects are known to live in huge nests and execute different tasks. For example, when walking close to a leafcutter ant nest, it might be possible to see many workers carrying leaves back home and, if the ants detect visitors as a threat, another type of behaviour can be displayed: an attack in the form of a painful bite. This organised division of labour has been maintaining the success of social insects for millions of years.

One essential aspect of the division of labour in social insects is age: bees start working inside the hive and, with time, they are ready for more risky activities, such as exploring their surroundings to protect the hive and collect resources.

Following a chronological timeline, in the first few days, the workers basically receive food and perform hygienic behaviour. Next, the initial work that they perform for their hives is building different structures like pots to store food and brood, and they also produce wax. Subsequently, bees start to work on brood care, filling their cells with food. At this stage, they can also feed the queen and some even work as a royal court for the queen.

Stingless bee “Uruçu-amarela” (Melipona flavolineata) queen and workers. Photo taken from the A.B.E.L.H.A. institution (abelha.org.br) and authored by Cristiano Menezes.

Following the timeline, workers start to collect the nectar brought to the hive by their nestmates to produce honey. Also, some workers will handle the waste within the hive: they organise piles of detritus to be disposed of outside later, for older workers. Finally, after some weeks, bees start to do short flights to recognise the vicinity close to the nest, the orientation flights.

Older bees have more experience and start to guard the hive and collect resources. Guards protect the hive from predators like spiders or the robber bee “abelha limão,” but also detect workers from the same species that may try to invade their hives. The guards can stay inside or outside the nest.

Lastly, usually after 4 weeks, bees have the function to go outside the nest and look for flowers to obtain food for their hives. At this point, they are already well-prepared to execute this challenging task. In particular, they can have an increase in structures in their brain and antennae that help in the perception of their surroundings.

Stingless bee “Jataí-da-terra” (Paratrigona subnuda) visiting strawberry flowers to collect pollen. Photo taken from the Embrapa institution (www.embrapa.br) and authored by Kátia Sampaio Malagodi-Braga.

When workers return to the nest with resources, they can follow two different trajectories: if they have pollen, they will deposit it into a pot themselves, but if they collect a liquid resource, such as nectar, they will probably transfer it to a younger bee. Interestingly, different bees may become specialists in collecting one type of resource; these can be pollen and nectar but also water, mud, or resin.

Even though this division of labour may be shared by many stingless bee species, there are always different possibilities to keep the hives working and bees can have flexibility in these behaviours according to the colony’s needs. Thus, if they need more food or have lost a considerable number of foragers, workers may start working outside earlier to supply the hive. It is also possible to have different roles; for example, Jatai bees have soldiers that are larger than regular workers and do not become foragers, they will have the same function until the end of

their lives. Additionally, some workers may never perform activities outside the hive and will just contribute to activities connected with building, cleaning, and feeding other bees.

Stingless bee “Jatai” (Tetragonisca angustula) guards hovering around the entrance tube. Photo authored by Christoph Grüter.

Organised and hard-working, stingless bees manage to execute all the tasks that they need to provide food and shelter for hundreds of workers. The incredible diversity of native stingless bee species favours the study of different behaviours and also the maintenance of the important ecological and cultural role of these tiny insects. Learning more about wild pollinators and fostering initiatives to preserve their populations is essential for a healthier environment.

Bibliography

Hölldobler, B., & Wilson, E. O. The leafcutter ants: civilization by instinct. WW Norton & Company, 2010.

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