Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stingless bees have their nests protected by soldiers

24.02.2017

Attacks by robber bees result in the evolution of larger guard bees and thus promote the division of labor in the hive

Although stingless bees do not have a sting to fend off enemies, they are nonetheless able to defend their hives against attacks. Only four years ago it was discovered that a Brazilian bee species, the Jatai bee, has a soldier caste. The slightly larger fighters guard the entrance to the nest and grip intruders with their powerful mandibles in the event of an attack.


Guardian bees of the species Scaptotrigona depilis at the entrance to their hive

photo/©: Christoph Grüter

Working in collaboration with Brazilian researchers at the University of São Paulo and Embrapa in Belém, biologists at Johannes Gutenberg University Mainz (JGU) managed to identify four further species which produce a special soldier caste to defend their nests.

"This is therefore not a solitary case, as it seems there is an astounding variety of social organization among other stingless honey bees," said Dr. Christoph Grüter of Mainz University. The scientists had examined a total of 28 different species from entirely different habitats in Brazil.

There are more than 500 species of stingless honey bees worldwide, 400 of them in Brazil alone. They form highly social societies with a queen and collect pollen in the same way as European honeybees. Many of the stingless bee species, however, are helplessly exposed to attacks by robbers. These robber bees, which also belong to the stingless bees, have given up foraging for pollen or nectar themselves.

Instead, they invade the nests of other bees and steal their honey and pollen, even wax and brood food. In 2012, however, Dr. Christoph Grüter and his colleagues discovered for the first time that parasitic robbers encounter difficulties when they assault a Jatai bee (Tetragonisca angustula) colony. The nest entrance is protected by guard bees which are larger than the hive’s other worker bees.

"Meanwhile we have established that the hive guards of a number of species out of the total of 28 we examined are larger than other worker bees. These soldiers are between 10 to 30 percent larger than the pollen foragers of the same colony," explained Grüter, adding that larger guards are better fighters.

Evolutionary biologists found large guard bees mainly in species that are subject to frequent attacks. The authors postulate that attacks by robbers are the driving force behind the evolution of a special caste among the worker bees and therefore represent the factor that has resulted in this more marked division of labor. "We were able to clearly link the activity of robber bees to the evolution of these soldiers," clarified Grüter. Analyses showed that such a differentiation among worker bees has occurred at least five times in the last 25 million years hand in hand with the appearance of parasitic robber bees.

Based on their findings, the team of researchers from Mainz and Brazil were able to publish a further new discovery. To date, it has been assumed that the division of labor among bees is determined primarily by age. Young bees take care of cleaning the nest and feeding the larvae. As they get older they move closer to the nest exit, from where they depart on foraging expeditions in search of food. It is a different matter with soldier bees. They are larger than their nest comrades from the moment they hatch, which means the division of labor in a hive is not dictated solely by the age of the insects but also by their morphology.

Photos:
http://www.uni-mainz.de/bilder_presse/10_zoologie_bienen_soldatinnen_01.jpg
Guardian bees of the species Scaptotrigona depilis at the entrance to their hive
photo/©: Christoph Grüter

http://www.uni-mainz.de/bilder_presse/10_zoologie_bienen_soldatinnen_02.jpg
Soldier bees of the species Tetragonisca angustula defending the entrance to their hive photo/©: Christoph Grüter

http://www.uni-mainz.de/bilder_presse/10_zoologie_bienen_soldatinnen_03.jpg
A soldier bee of the species Tetragonisca angustula (bottom) next to a forager from the same hive. The photo was taken shortly after hatching, which is why the bees are still without pigmentation.
photo/©: Christoph Grüter

Publication:
Christoph Grüter et al.
Repeated evolution of soldier sub-castes suggests parasitism drives social complexity in stingless bees
Nature Communications, 23 February 2017
DOI: 10.1038/s41467-016-0012-y

Further information:
Dr. Christoph Grüter
Behavioral Ecology and Social Evolution Group
Institute of Organismic and Molecular Evolutionary Biology
Johannes Gutenberg University Mainz (JGU)
55099 Mainz, GERMANY
phone +49 6131 39-27843
fax +49 6131 39-27850
e-mail: cgrueter@uni-mainz.de
http://www.bio.uni-mainz.de/zoo/evobio/513_ENG_HTML.php

Weitere Informationen:

http://www.bio.uni-mainz.de/zoo/evobio/index_ENG.php

Petra Giegerich | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>