Stingless bees: Recruitment and communication II

Communication behavior is highly developed in eusocial insects like bees and ants. Stingless bees live in the tropics and subtropics in colonies of up to thousands of individuals. Like honeybees they recruit nestmates when exploiting food sources. Although they do not have anything like the famous honeybee dance, their recruitment is very efficient. How do they accomplish this? The subject of this project is the communication, navigation, and sensory biology associated with this remarkable behavior. Three main questions will be addressed. (i) Concentrating on the genus Melipona, the project will contribute towards a clarification of the question whether there is symbolic communication or not. Do the bees communicate by using "symbols", that is, do they transform information on the distance and direction of the food source into referential signals? There is an ongoing controversy in regard to this fundamental question which suffers from the fact that several potentially illuminating experiments have not been done yet. Among these are carefully executed "fan experiments", observation of the flight paths of newly recruited bees, and manipulation of the sound / vibration signals of the foragers. (ii) The project will examine proximate mechanisms involved in the recruitment of nestmates using a process oriented approach and applying modern technology like laser vibrometry and 3D-anemometry. Thus the attenuation and transformation of the vibrations and sound signals on their way through various nest structures and from the sending bee to the receiver bee will be measured precisely. This will enable us to predict what the receiver bees and other nestmates may indeed experience. Apart from the vibrational signals the origin, properties and significance of various scent marks used by stingless bees shall be examined using bioassays, chemical analyses and electrophysiological methods. (iii) The project will address the diversity of recruitment behavior found in stingless bees and its adaptation to particular ecological conditions and to resource partitioning. Specifically, two species of the Trigona-group will be studied, which were never suggested to use "symbolic communication" like Melipona but seem to be at least as efficient recruiters. Unlike other representatives of the Trigona-group one of these closely related species does not lay a scent trail in order to guide recruits to the food. The intranidal behavior of the two species, which behave very differently outside their nests, shall be compared to better understand the meaning of various potential signals. Much of the project work has to be carried out in Brazil and Central America. It brings together experts from Brazil, Germany and Austria. Considering the increasing awareness for the importance of stingless bees as pollinators and apiculture the present project also relates to applied aspects.

Communication behavior is highly developed in eusocial insects like bees and ants. Stingless bees live in the tropics and subtropics in colonies of up to thousands of individuals. Like honeybees they recruit nestmates when exploiting food sources. Although they do not have anything like the famous honeybee dance, their recruitment is very efficient. How do they accomplish this? The subject of this project is the communication, navigation, and sensory biology associated with this remarkable behavior. Three main questions will be addressed. 1. Concentrating on the genus Melipona, the project will contribute towards a clarification of the question whether there is symbolic communication or not. Do the bees communicate by using "symbols", that is, do they transform information on the distance and direction of the food source into referential signals? There is an ongoing controversy in regard to this fundamental question which suffers from the fact that several potentially illuminating experiments have not been done yet. Among these are carefully executed "fan experiments", observation of the flight paths of newly recruited bees, and manipulation of the sound / vibration signals of the foragers. 2. The project will examine proximate mechanisms involved in the recruitment of nestmates using a process oriented approach and applying modern technology like laser vibrometry and 3D-anemometry. Thus the attenuation and transformation of the vibrations and sound signals on their way through various nest structures and from the sending bee to the receiver bee will be measured precisely. This will enable us to predict what the receiver bees and other nestmates may indeed experience. Apart from the vibrational signals the origin, properties and significance of various scent marks used by stingless bees shall be examined using bioassays, chemical analyses and electrophysiological methods. 3. The project will address the diversity of recruitment behavior found in stingless bees and its adaptation to particular ecological conditions and to resource partitioning. Specifically, two species of the Trigona-group will be studied, which were never suggested to use "symbolic communication" like Melipona but seem to be at least as efficient recruiters. Unlike other representatives of the Trigona-group one of these closely related species does not lay a scent trail in order to guide recruits to the food. The intranidal behavior of the two species, which behave very differently outside their nests, shall be compared to better understand the meaning of various potential signals. Much of the project work has to be carried out in Brazil and Central America. It brings together experts from Brazil, Germany and Austria. Considering the increasing awareness for the importance of stingless bees as pollinators and apiculture the present project also relates to applied aspects.