Preparation of feather mites
On one hand, the production of permanent preparations is necessary for the immediate determination of species, on the other hand later corrections due to new discoveries are made possible.
These preparations can also be employed for the taking of photographs. Concerning morphological and systematical studies of these parasites, it is unavoidable to set up a collection of permanently prepared mites.
Preparation methods demanding several work cycles during which mites could get damaged or lost are little useful, since feather mites are small and fragile specimen and since there are mostly only a few individuals available.
The following methods have proven reliable in our preparation:
Investigation of the feather under the stereo microscope and picking up of the mite with a needle (normally used for insect preparation purposes). If necessary, the needle can be moistened.
Further, the mite is placed into a drop of Berlese-Mixture placed on a microscope slide.
Then, a cover glass is placed on top. Here, round shaped cover glasses enable the spreading of Berlese-Mixture continuously to all sides, the mite remaining in the centre.
In the next step, the slide is immediately placed on a 60° Celsius warm heating plate. By it, the spreading of the Berlese-mixture is being accelerated and mites that are still alive are killed at once.
After remaining on the heat plate (for approximately 2-12 hours) the mites are stretching their limbs, which is important for their identification.
In the warm surrounding, the Berlese-mixture can better diffuse into the mite and lighten it due to its strong refraction of light. Details, such as bristles and scutum appear clearer.
Since Berlese-mixture is a water soluble embedding, it is also possible to remove the preparation after solving the slide in Aqua dest. (after removing the cover glass) in order to preserve it in alcohol. The lightening of the preparation is then neutralized.
In case the preparation shall remain in a permanent collection, we recommend embedding the slide (after several months of drying in a dry room or in a drying board with a temperature of 28-30 ° Celsius) in a non water soluble medium.
In this case we are applying “Roti Histokitt”, an embedding medium used in the fields of histology, which air seals the Berlese. This work cycle is recommended, since Berlese-mixture is hygroscopic.
The preparations produced this way are enduring. Throughout the past seven years we have been collecting personal experiences concerning their durability. On account of the excellent quality after this period of time, we hope on a considerably longer durability.
Since these preparations meet all requirements for microphotography, it is useful to set up a photo collection in addition.
Ingredients and production of Berlese-mixture:
- 30 g of Gummi Arabicum in pieces are solved in 50 ml Aqua dest. (takes about 3 days)
- 20 ml of Glycerol and 200 g crystalline Chloralhydrat are added (solving time further 3 days)
- the viscous solution needs to be stirred well and filtered (filtration time 3-4 days); in total, the mixture is decreasing about one third in volume