Due to the use of pesticides in agriculture, but also due to Varroa mites (Varroa destructor), the stress on bee colonies has steadily increased in recent decades. The use of organic acids against Varroa mites also increases the pressure on the bees, which is why many beekeepers and other bee enthusiasts are looking for a biological alternative. Here, the book scorpion could play a significant role.

The most dangerous enemy of the bee – the Varroa mite

Varroa mites are tiny reddish-brown parasites of honey bees that do not invade their hosts themselves, but infest them from the outside. Although Varroa mites can feed and live on adult honey bees, they feed and reproduce primarily on larvae and pupae in developing brood, causing deformities and weakening of honey bees as well as transmission of numerous viruses. This parasite is considered one of the main reasons for the current phenomenon of bee mortality and, according to the German Bee Monitoring (DeBiM), responsible for the death of 10-15% of bee colonies per year. Although bee colonies show few symptoms in the early stages of an infestation and therefore often go unnoticed by the layperson, an infestation can build up over 3-4 years, leaving a colony with physical impairments such as impaired flight behavior, crippled limbs, reduced performance and shortened life span. Particularly insidious here is that the Varroa mite attacks the fat bodies of the bees, which, in analogy to the liver in humans, are responsible for the detoxification of the bee body. As a result, the bee is less able to detoxify foreign pollutants and pesticides and similar substances used to help the bee get rid of the mite infestation can do more harm than good. [[1], [2], [3]]

The bee’s best friend – the book scorpion

The book scorpion (Chelifer cancroides) can provide significant relief to the bee colony. The small pseudoscorpions grow between 2.5 and 4.5 mm in size, are harmless to humans and live with bees in a peaceful symbiotic relationship for mutual benefit. In particular, Torben Schiffer, a biologist from Hamburg, Germany, has spent the last 15 years intensively studying the effect of the book scorpion on Varroa mite infestation in bee colonies. His studies were preceded by the fact that book scorpions are found in all wild bee colonies worldwide. It was not until the introduction of hives made of sawn and thus smooth wood or later polystyrene structures that any space in the hive where the book scorpions could have retreated or nested disappeared. As long as the bees were kept in straw baskets or hives made of rough wood, this was still possible. So the type of hives used is critical to the ability to work with the book scorpions.

If the pseudoscorpions succeed in establishing themselves in the hives, they prey on Varroa mites and other prey, stinging, poisoning and sucking them dry. Each pseudoscorpion can consume one to nine varroa mites per day.

[1] https://www.br.de/wissen/bienen-varroamilbe-bienensterben-lithiumchlorid-100.html

[2] https://bienenmonitoring.uni-hohenheim.de/

[3] https://beeaware.org.au/archive-pest/varroa-mites/

Empirical research also confirms the positive effect of book scorpions on bee population health and their advantages over classical pesticides. In 2017, Hans-Jürgen Ratsch et al. conducted an experiment on the topic. In order to achieve statistical significance, three hives were set up at each of 13 locations in the Hannover region. One of these hives was made of wood and was equipped with 150 book scorpions, another was also made of wood and the third was a standard styrofoam hive. To measure the intensity of Varroa infestation of the hives, the number of mites that fell from each hive onto a designated drawer below the hive was recorded weekly between the 22nd and 52nd calendar week.

Quelle: https://www.beeculture.com/wp-content/uploads/2018/08/chel3.png

The results of the research group clearly show a significantly lower burden of Varroa mites in the hives that were additionally equipped with book scorpions. The researchers considered that it can be concluded that the statistically significant result that varroa infestation is lower in the hives equipped with book scorpions is neither a coincidence nor a measurement error. [[1], [2], [3]]

[1] http://ujubee.com/?p=1104

[2] https://www.beeculture.com/chelifers-or-pseudoscorpions-as-varroa-control-agents/

[3] https://beenature-project.com/

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