D. Förderung des wissenschaftlichen Nachwuchses


Figure 2. Long-term tracking ofhoneybees and colony heat stress experiments. (a) The BeesBook tracking System
used to individually mark honey bees in the observation hive, and three example trajectories (white, grey, black)
overlaid on the comb Substrates, (b) Thefraction of time bees spend on different comb Substrates changes with
age, but shows considerable Variation. Shoivn is the time bees spent on agiven Substrate on agiven day (top row:
28 July, bottom row: /7 Twgf Points represent an averagefor each individual bee; boxplots shoiv distributions
across the age-matched cohorts. Cohorts are named alphabetically according to birth date, shown in the legend,
(c) Shiftingfrom colony-level homeostasis to experimental manipulations, we piloted heat-stress trials this year.
Room temp is raised to 45 °C over three hours (left), ivhich increases the temperature of the brood. In response,
thousands of workers evacuate the nest tofacilitate nest cooling (Images at right).

entire beeswax nest. To prevent overheating, bees must coordinate their behavior
such that some evacuate, others perform fanning to circulate air, and others coll-
ect water to use for evaporative cooling. We performed heat stress experiments by
raising the temperature of the room (not the observation hive) to 45 °C over three
hours. Düring the heat stress, the colony successfully maintained its brood below
room temp (Fig. 2c), and we observed thousands of workers evacuating the nest
to facilitate nest cooling. In the coming months we will analyze the task usage, for
example in the form of the Substrate averages shown in Fig. 2b, bcfore and after the
heat stress, to determine how a decentralized collective organizes a partial evacuati-
on, as well as the subsequent re-entry after the heat stress has passed.
Outlook
In the cellular System we are currently designing experiments where we actively
manipulate the group composition using genetic and molecular tools. This allows
us to ask how the presence of a small number of cells with different properties

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