Chennai, January 11, 2012: A team of scientists from the Laboratory of Apiculture and Social Insects, University of Sussex (LASI) and the University of São Paulo discovered distinct soldier bees among workers of the stingless bee, Tetragonisca angustula that is commonly found in Brazil. The research leading to this discovery is published in a paper* in the online issue of the Proceedings of the National Academy of Sciences, USA. Following is the press release News relating to this discovery from the University of Sussex.
* Reference cited: Grüter, C.,Menezes, C., Imperatriz-Fonseca, V.L. and Ratnieks, F.L.W. 2012. A morphologically specialized soldier caste improves colony defense in a neotropical eusocial bee. Proceedings of the National Academy of Sciences, Published online before print January 9, 2012. doi:10.1073/pnas.1112298109
UNIVERSITY OF SUSSEX
Sussex scientists discover first-ever bee 'soldier'
University of Sussex scientists working with researchers in Brazil have identified the first example of a 'soldier' bee.
The discovery was made by a team of scientists from the University of Sussex and the University of São Paulo including Professor Francis Ratnieks and Dr. Christoph Grüter from the University of Sussex Laboratory of Apiculture and Social Insects.
The team studied a common tropical stingless bee Tetragonisca angustula in São Paulo State in Brazil where it is known locally as Jatai. It nests in tree and wall cavities. Each nest has one queen and up to 10,000 workers.
Insect societies such as the Jatai's are defined by cooperative and altruistic behaviour, with the workers caring for the nest and the queen's offspring. This lifestyle also includes the division of labour among workers.
The research, published today (Monday 9 January 2012) in the journal Proceedings of the National Academy of Sciences (PNAS) states that:
- Jatai guard bees are 30 per cent heavier than their forager nestmates;
- they differ slightly in shape from foragers, with disproportionately larger legs and smaller heads;
- approximately one per cent of worker bees reared in a colony are soldier-sized;
- Jatai soldiers stand on the nest entrance tube and also hover near the entrance where they provide "early warning" detection of enemy attack.
Like other social insects, Jatai use guard workers to protect the nest. A previous study by the team had shown that these guards were specialists who performed guarding duties for far longer (up to three weeks) than other types of worker bee, such as the honey bee, who spend just one day guarding the nest, progressing to other tasks as they get older.
The new research sows that Jatai guards, unlike their honey bee counterparts, are morphologically (physically) specialised to perform a particular task, being consistently larger than their nest mates.
Having larger-bodied guards is important for nest-defence, as they are better at fighting one of Jatai's main enemies - the robber bee Lestrimelitta limao, which can kill off many colonies when raiding nests for food (See Videos of Jatai guard bees). These guards, then, are more like the 'soldier' workers found in some ant and termite colonies.
Even though the Jatai guard lacks a sting and is eventually killed, it can clamp its head onto the wing of a robber bee, preventing it from flying.
The discovery is significant in terms of the evolution of advanced insect societies. Large-bodied soldier workers have long been known in ants and termites, but this is the first evidence of a soldier bee - a worker physically designed for active defence of the nest.
Professor Ratnieks says: "Stingless bees are not defenceless. Jatai is one of the most common bees found in Brazil, but its sophisticated defences make it one of the most amazing."
Last updated: Tuesday, 10 January 2012