Date: February 23, 2017
Source: Universität Mainz
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.