Ultrasonic Hive International

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Ultrasonic emitter for combating varroosis

The troublesome parasite of the honey bee – varroa destructor – came to Europe 40 years ago and has since been fought in various ways. The bee-infected family, in the absence of interference by the beekeeper, dies within two years, and sometimes even within a few months.

A common method of combating varroosis is fumigation with chemicals containing pesticides, most often amitrase. When burning amitrase, varroosis located on bees falls on the bottom of the hive. Fumigation with chemical agents has negative side effects, such as shortened life expectancy of bee mothers and a reduced number of eggs laid. Poisonous varroosis pesticides remain in wax combs and penetrate into honey, which is undesirable due to the stated carcinogenicity of amitrase. In addition, varroosis hidden during a smoky procedure in sealed cells with developing bees, continues its reproductive process without hindrance. Many chemicals have lost their effectiveness due to the resistance of varroosis to poisonous ingredients, e.g. fluvalinate, flumethrin. Attempts to eliminate varroosis by physical methods by briefly raising the temperature inside the hive to 42 oC, although effective [1], but quite complicated in implementation, have not gained wider application. Similarly, the proposed methods based on plant extracts such as yew isolates [2] or a preparation containing 2-undecanone [3] have not found wider application so far. In 2004, Karl Ruemmelin [4] initiated research into the use of a physical method using ultrasound to combat varroosis. In recent years, these investigations have taken the form of systematic research, which was reflected at the Apimondia Congress in Istanbul (2017), where the use of ultrasounds to combat varroosis was identified as revolutionary. In turn, in a publication from 2018, a team of Irish researchers confirmed that acoustic waves are not harmful to bees in a wide frequency range 

[5]. No changes in bee behavior were observed when the ultrasonic volume range was between 90 and 110 dB at frequencies in the range from 14 kHz to 80 kHz. During the effect of ultrasound on bees,  32 mites drop  in time of 30 minutes. It is postulated that ultrasound makes it difficult for mature varroosis to suck to the abdomen of a bee to eat fat tissue. The ambulacra, or foot pads located at the ends of the Varroa’s legs are relaxed under the influence of ultrasounds, which makes it easier for bees to remove Varroosis from their abdomen during mutual care [5].Ultrasounds vibrate not only four pairs of varroosis legs, one of which acts as an antenna, but above all cause dysfunction of two sensory pedipalpes and two chelicerae. Pedipalpes adjacent to the mouthpart receive the smallest vibrations coming from the environment. It should be emphasized, that the legs with tarsuses and pedipales are equipped with numerous chemosensors and mechanosensors in the form of hairs (Fig. 1), whose lengths range from a few μm to over 100 μm. They can act as a specific eardrum recording the smallest acoustic vibrations. The destructive effect of ultrasounds on the development of varroosis may be the result of acoustic phenomena such as interference resulting from ultrasound reflection within the bee larva. As a result, the ultrasound field received by the sensory pedipalpes significantly interferes with the process of nourishing varroosis at the developmental stage. Malnourished varroosis larvae do not reach the imago stage and fall to the bottom of the hive when the young bee leaves the cell. Recent studies have shown that varroosis mainly feeds on fat body tissue, not hemolymph [6].

The main operation of the ultrasonic method (Fig. 2) relates to the reproductive period of varroosis, which lasts about seven days. Varroosis lays eggs on bee larvae in capped wax cells of the comb. Varroosis larvae in the protonymph, deutonimph and subsequent deutochrysalis stages ( Fig. 3) , using jaw-tentacles, feed on fat tissue of larvae and bee nymphs, which significantly weakens young bees. During such contact, varroosis carries numerous viruses inside the bee that destroy bee colonies. These facts are currently the most serious threat to a honey bee.The destructive impact of ultrasounds on the development of varroosis may be the result of a disturbance in the functioning of mechanosensors. Apparently, the acoustic field generated by the sonic emitter has a significant impact on communication between mature female varroosis and its offspring. Our microscopic observations, documented by a film, showed that female varroosis perform fast and dynamic leg movements, generating local acoustic vibrations. Such vibrations, picked up by mechanosensors, can be helpful for their growing offspring in locating punctures of the larva cuticle and the pupae, as well as in the recalling of the male by mature sisters. As a result, the external acoustic field significantly interferes with the development of varroosis in bee cells.
Confirmation of the above hypothesis are studies showing the loss of the ability to register volatile pheromones by varroosis, whose legs were covered with varnish [C. K. Häussermann et al. 2015]. The authors of this work, covering the legs with nail varnish, significantly eliminated chemosensors, which they emphasize in the conclusions, but also mechanosensors were affected. It is likely that each chemosensor also acts as a mechanosensor.  In order to obtain satisfactory results of the varroosis elimination, it is necessary to use a reticulated hygienic bottom in the hive, which will prevent contact of the varroosis with the bee again. Our research confirmed the full usefulness of the constructed ultrasonic emitter in the method of combating varroosis in bee families. Placing the ultrasonic emitter in the hive at the beginning of April for a period of 21 days resulted in zero natural precipitation until August 11. In addition, this family uses a partial work frame in which – left without wax foundation – a vertical, 10 cm wide side belt was built by bees with drone cells. The development process of varroosis, which is heavily concentrated on drone cells, has been stopped as a result of ultrasound emitter.  In ultrasonically treated new families, the average daily fall of varroosis observed in the second half of August was 60, including varroosis at the protonimfa and deteronympha stages. Delayed ultrasound treatment, which began on August 8 and continued until October 7, resulted in a total of 3147 pieces of varroosis. Due to the inevitable varroosis reinfection, the effectiveness of the ultrasonic varroosis control method is about 90% using three cycles per year, lasting 21 days for each a bee family, with breaks of up to six weeks. The 21-day period of presence of ultrasound in a bee family eliminates three successive hatching of varroosis in the hive. To limit reinfection through silent robberies, it is necessary to use reticulated screened anti-robbery screens at the hive outlets, and / or inlet slides to help bees defend against robbers who not only steal honey but also bring varroosis.

 

Fig. 1. The first pair of legs and two sensory pedipalps of varroose coated with numerous chemosensors and mechanosensors in the form of hairs. Photograph taken on a scanning electron microscope by M. Vlimant, University of Neuchâtel. [F-X Dillier et al., 2006] (with the consent of the authors).

Fig. 2. Ultrasonic frame with sonic emitter containing five visible ultrasonic piezoelectric heads. The photovoltaic panel visible on the right and the battery (located under the hive) constitute the power supply system.

THE ULTRASONIC FRAME

he main element of the ultrasonic frame is the electronic module consisting of a generator and five piezoelectric ultrasonic heads. The electronic module ensures a homogeneous high-power acoustic field and can be placed in a frame of any size, regardless of the type of hive. The ultrasonic frame should be placed tangentially to the nest in the hive. It is recommended to change the position of the frame from the right side of the socket to the left side in the middle of the exposure cycle.  

The electronic module itself protected with plastic foil can be placed directly above the socket, on the upper slats of the frames, after removing any beams, to ensure the penetration of ultrasound in the streets between the frames of the socket. In order to avoid building free spaces within the ultrasonic frame, as well as for hygienic reasons, it should be protected with a thin plastic film, which absorbs ultrasound to a slight extent.

In addition, the sonic emitter itself – protected by a plastic film – can be placed under the bottom of the hive, in a suitable container to protect against moisture (in all types of hives).

The method of ultrasound control of varroosis – due to unavoidable reinfections – reaches up to 90% effectiveness in the summer, while in the winter the effectiveness of the method reaches 100%. The method is completely safe for the beekeeper, development and work of bees, and also does not bring any negative effects to wax comb and honey.

Fig. 3. Characteristic ultrasonic fall of varroosis. In addition to three adult females that are clearly visible, noticeable places of varroosis spread in the stages of protonimfa and deutonimfa (left side), whose enlarged images are visible on the right.

Fig. 4. (a) Full and (b) partial work frame (drone cells in the middle lane) and (c) drone larvae and pupae completely devoid of varroosis due to the sonic emitter.

Fig. 5. Schedule for performing varroosis removal in three bee families using one ultrasonic frame, starting from family No. 2. From May 15 to September 22, the frame is used continuously to resume the autumn cycle on October 15 in beehive No. 2.

References:

  1. Patent US 2014/0134920 A1
  2. Patent  PL 218627
  3. Patent  PL 228 027 B1
  4. Patent DE10161677B4
  5. B. C. Barry, W. M. D. Wright, L. Verstraten, (2018), The Use of Airborne Ultrasound for Varroa    Destructor Mite Control in Beehives,  DOI: 10.1109/ULTSYM.2018.8580160
  6. S. Ramsey et al., Varroa destructor feeds primarily on honey bee fat body tissue and not hemolymph, PNAS, January 29, 2019,  vol. 116, no. 5
  7.  M. Surowiec, T. Surowiec, Patent Claim  P.432575,  WIPO ST 10/C PL432575

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Email

varroa.stop@ultrasonicemitter.pl

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