The bee whisperer

An article out of the newsletter of the MPI for chemistry

Around the back of the MPIC site, there’s a buzzing and humming in the air. Behind the grass-covered hills, between the cherry trees, there are several beehives housing a total of eight small bee colonies, each numbering six to eight thousand bees.

The bee population, which was established on the Institute’s grounds in 2019, is the object of a special research project by Dr. Stanislav Balouchev, physicist at the neighboring Max Planck Institute for Polymer Research, and Prof. Katharina Landfester, director of the working group “Physical Chemistry of Polymers”.

What led you to begin researching bees?

I am a laser physicist by training, but I also have a strong connection to biology. For 20 years, I have been working at the MPI for Polymer Research with organic chemists and now with microbiologists as well. My motivation to study bee colonies is also somewhat personal. I have a connection to the land and agriculture that comes from my grandfather, who also kept bees.

In our laboratories, we measure the spatial distribution of temperature and oxygen in cell cultures exposed to different stresses. We recently patented a minimally invasive, fully optical regulation process for two-dimensional temperature and oxygen distribution in cell cultures. This form of measurement provides vital insights into the state of the cell culture.

The bee project actually serves as an analogy for this, as it also focuses on achieving the highest resolution for the measurement of temperature distribution – just in a beehive as opposed to a laboratory.

How long has your bee research project been running and what is its objective?

In our role as scientists in Prof. Katharina Landfester’s working group, we found out about the mass death of the western honey bee Apis mellifera and the phenomenon of Colony Collapse Disorder (CCD). We then asked ourselves: Is there an objective and measurable parameter that determines the health of the bee colony as a whole? We created an analogy with a human body, where the distribution of body temperature is crucial to determining health. We believe that this spatial distribution of temperature in the bee-colony superorganism has not yet been researched enough.

In 2018, we began the project of measuring the spatial distribution of temperature in a bee colony, and from July 1, 2019, the Volkswagen Foundation lent its support to our project as part of the “Experiment!” initiative.

What benefits could there be to your findings?

With three-dimensional temperature measurement, we want to find out if and how we can adopt the evolutionary strategy of the Apis cerana variety of bees, which is common in Indochina. This species is fighting the invasive Varroa destructor mite by increasing the temperature in the nest. Our European honey bees can’t protect themselves from mites in this way and the parasites cause them to develop the disease varroasis, which can currently only be treated with chemicals, so we are hoping to find a natural alternative treatment for the disease.

We also want to make our experimental data available to the scientific and broader public as a contribution to our general fundamental understanding of social insects.

How does your method of temperature measurement work?

First, we need to determine which temperature is optimal for the development of the bee colony. This temperature is measured just beneath the surface of the honeycomb, where the larvae develop.

In this phase, the test bee colony is settled onto six electronic honeycombs, each equipped with 91 small temperature sensors. In addition to this, there are four heat sources around each temperature sensor that are individually controlled by computer systems. Our technology makes it possible to measure the local temperature in the bee nest in over 540 areas with a temporal resolution of one minute. In the space of a year, a large amount of data can be collected to describe the thermal behavior of an established bee colony in each phase of its development.

At the moment, we are still using conventional semiconductor-based sensors, but in the next stage of the project we want to move on to using miniature polymer-based temperature sensors. Our plan is to use a 3D printer to print these sensors directly onto a base, which will allow us to increase the resolution and record the temperature in each individual honeycomb cell.

Do the electronic honeycombs not disturb the bees?

It certainly wasn’t easy to produce honeycombs with sensors that the bees would not view as foreign bodies – the key is the natural oscillation frequency of the sensor-laden honeycomb. To begin with, the wax plates became unstuck from the glass surface while the bees were building the honeycomb, so to mitigate this, we covered the first sensor plates with a thin sheet of wool, poured liquid wax onto it and embossed the pattern of a honeycomb directly into it. We later shifted to using polyester fabric, as it is just as waterproof as the wax. The bees have thus accepted our electronic honeycombs, even though they are not their own! The electronic honeycombs with sensors were designed by our electronics laboratory at the MPIP, which also provided the computer and software required for measurements, while the electronic honeycombs were produced in the electronics group at the MPIC.

Have you already started to actively regulate the temperature in the beehive?

We do have the technology to do that, but for now we are going to focus on measurement. We first want to understand the bees before we interfere with life in the hive. We could try raising the temperature, but we do not yet know how arbitrarily increasing the temperature would affect the superorganism. Before we decide to do this, we need more reliable data.

Does this mean that the beehives will be staying at the MPI for Chemistry for some time to come?

Yes, the large green space on site is perfect for our colonies and very convenient for us to access.