Nav: Home

Stingless bees have their nests protected by soldiers

February 23, 2017

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. Working in collaboration with Brazilian researchers at the University of Sao 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.
-end-
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

Johannes Gutenberg Universitaet Mainz

Related Evolution Articles:

Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?
Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.
Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.
Evolution of aesthetic dentistry
One of the main goals of dental treatment is to mimic teeth and design smiles in the most natural and aesthetic manner, based on the individual and specific needs of the patient.
An evolution in the understanding of evolution
In an open-source research paper, a UVA Engineering professor and her former Ph.D. student share a new, more accurate method for modeling evolutionary change.
Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
More Evolution News and Evolution Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.