Use hive scales and brood sensors to monitor egg-laying and oxalic acid success.

In this tutorial we explain how you can use the brood sensors to monitor the laying process and how youcan use oxalic acid-based BIO treatments.

For this explanation we rely on the recording of the resumption of oviposition at the end of January.

If you want to have this tool at home you must equip your hives with the complete configuration MULTISCALE as well as the weather sensor and the brood probes.

Having the right configuration

full multistage conguration
Configuration MULTISCALE complete with 4 brood sensors and an external weather sensor.

1 - The external sensor, also called "Weather" sensor

In the configuration Multiscale, we propose a sensor called "Weather". To interpret the brood curves it is totally indispensable! Indeed this sensor is not intended to provide the weather conditions, but it is well intended to be an external reference to the hive.

Indeed, all the brood data are interpreted by the analysis of the difference between the inside of the hive and the outside of the hive.

2 - The 4 brood collectors

Multiscale offers 4 brood load cells, one on each lane, which can be easily added to the scales using a special connection cable.

When working on the bunch, make sure that the brood sensors are always in the centre of the bunch, otherwise your temperature and humidity measurements on the brood will be distorted.

Reading and interpreting the brood chart

The sensor graph seems a bit complex at first glance, but if you take the time to decode it, you can see that it is very simple to read. It is made up of 2 distinct graphs.
The first one concerns the temperatures and includes:
- the 4 brood temperatures
- the outside air temperature (in magenta on the graph, named: Ext.)
The second one concerns the humidity and includes:
- the 4 brood humidity measurements
- the outside air humidity measurement (in magenta on the graph, named: Ext.)
Only the comparison of the 4 channels in humidity and temperature compared to the outside values will give you answers as to the presence of brood or not.

Example of resumption of egg-laying at the beginning of February
(graph over 2 months)

1 - Recovery of the brood at the end of winter (beginning of February)

The graph below clearly shows a change in the temperature and humidity curves from the beginning of February. It can be seen that on days with good weather in January, the internal temperatures of the hives rose sharply, but the recovery did not take place until the temperature remained above 5°C for several days.

2 - temperature stabilization between 30°C and 35°C

We can clearly see that from the beginning of February the temperatures suddenly stabilize between 30°C and 35°C. The P1-Black curve, on the other hand, takes longer to really reach the "5°C. This probably means that the sensor is not really in the center of the cluster and therefore only partially benefits from the heating of the bees.

3 - humidity stabilization between 45% and 55%.

As with the temperature, it is clear that suddenly from the beginning of February the humidity stabilizes between 45% and 55%.

The visualization of the stabilization of the 2 values: Temperature and Humidity, allows us to deduce that the laying resumed in these 4 hives at the beginning of February

The phenomenon of regulation of the Temperature and Humidity in a fixed range by the bees is called HOMEOSTASIA.

Successful BIO treatment with oxalic acid

The principle of the organic treatment consists of intervening twice:
- Once in the summer by blocking the egg laying voluntarily and diffusing dripping oxalic acid
- Once in the winter by using the natural egg laying blocker to make a second diffusion of oxalic acid by sublimation
These two treatments must be accompanied by a measurement of the infestation rate on the diaper to be sure of the level of varroa infestation.

1 - Intervening in summer

The principle of the summer intervention is to take advantage of the summer honeydew to lock the queen in a cage. The bigger the cage is, the less queen will be lost (the ideal being to block it on a whole frame where she can lay eggs). After three weeks, the queen is decanted and the bunch is sprinkled with oxalic acid. Monitoring the brood temperature is not fundamental but will go well with the monitoring of this operation.

2 - Intervening in winter

Unfortunately it is not possible to be satisfied with just one summer treatment. A sublimation of oxalic acid must also be carried out in winter (see 2 in some cases). At the end of October, position the brood collectors in the centre of the bunches and you will clearly see the laying of eggs stop. This results in a progressive loss of homeostasis conditions. You will thus clearly know when to intervene to be really out of the brood at the time of treatment and thus be effective.

Devices that do not provide egg-laying status

If you wish to use other materials than MULTISCALE, this is possible but only probes that dive to the center of the cluster can really give usable information. The boxes and the probes located ON the frames (number 1 and 2 on the picture below) do not give effective information on the state of the egg-laying, especially in winter. The large boxes at the edge of the frame also do not give the actual condition of the egg laying.