Hannah Marie Troppens:
Analysis of the proximity and trophallaxis network in honeybees
Honeybee colonies are complex social systems that consist of many individuals interacting with each other without a central control. The organisation of tasks is determined by temporal polyethism: the task repertoire a bee performs changes with age. Observing individual honeybees and their interactions with each other gives insight into their collective behaviour. There are different forms of social interactions in a bee hive such as physical contact (proximity), mouth-to-mouth food exchange (trophallaxis) and waggle dancing. An approach to the analysis on interactions is constructing a social network, where bees form the nodes and interactions the edges of the network. Other works have already analysed netowrks deriving from interactions in a honeybee hive. So far, no work has compared the trophallaxis and proximity network measures using data of all bees in the colony.
The automatically collected data of a honeybee colony by the BeesBook Project is used to construct the network. The biological age and network age, capturing a bee's current role in the hive, of each bee is available.
The goal of this thesis is to analyse and quantify the differences of the proximity network and the trophallaxis network with a focus on task repertoire. One part of the analysis is exploring the daily interactions between pairs of bees using date of one week. Afterwards, network measures are calculated for the proximity and trophallaxis network based on the data of one day. Finally, networks for every four hours of the day are compared.
While the analysis of the weekly data shows a high similarity between both types of interactions, the analysis of network measures reveals great dissimilarities. For the trophallaxis network, the network measures of nodes are negatively correlated to network age. In the proximity network, on the other hand, young bees have the highest values, but older bees also show high values. The proximity interactions of old bees are dependent on the circadian cycle, whereas the trophallaxis interactions do not vary strongly at different times of the day.
The results for both networks suggest a strong link between network measures and taks allocation in a honeybee colony.