17.04.2022
How to dissect a spermathecae with lactic acid from a alcohol preserved tarantula
More and more tarantula keepers are interested in correctly identifying the tarantulas available in the community. Not only when it comes to species identification, but also and especially when it comes to sex determination. As a result, they also have to deal with the techniques of spermathecae preparation. In most cases, the spermathecae are prepared just from exuvia by interested tarantula keepers. However, when it comes to tarantulas preserved in alcohol, the dissection of the spermatheca is much more difficult or requires a different technique! Since the article by Volker von Wirth 2006 concerning the following methode, the technique described below for the fast preparation of tarantula spermathecae from spiders preserved in alcohol has often been used and cited, e.g. for scientific publications (see West et al. 2012, Nunn et al. 2016, Huesser 2018, Drohlshagen & Bäckstam 2021).
In order to support this type of spermathecae preparation again for all those who are interested, we explain step by step how to proceed here. The problem with preparing the spermathecae from a tarantula is the fact that there is a lot of fleshy and greasy components attached to the spermathecae. You can try to remove these by scraping them off with a dissecting needle, but this is usually not so clean and you can quickly injure the spermathecae. The advantage of the following type of spermathecae preparation compared to other techniques used by other tarantula systematists (trypsin enzyme solution, clove oil ...) is the speed with which you get these disturbing fleshy and greasy components from the spermathecae removed by maceration.
How to do this is shown below:
PIC 1 – 3: the genital plate between the anterior book lungs is cut out of the dead tarantula in a trapezoidal shape with a deep incision (see orange trapezium), since the spermathecae can be found on the inside of this genital plate.
PIC 4: You now fill about 1.5 ml of lactic acid (Acidum lacticum) into a heat-resistant test tube, place a small stone in the test tube to prevent delayed boiling and finally put the genital plate with the spermathecae in the test tube.
PIC 5 – 6: Now you heat this mixture for 2 – 3 minutes and bring it to the boil. The more fat and meat is macerated from the spermathecae, the more amber colored the mixture becomes. If there is still too much meat hanging from the spermathecae, go on and cook the whole thing for a few more minutes until all the meat and fat has macerated.
PIC 7 – 8: Once the maceration is complete, the test tube has to be removed from the heat source and the genital plate hast to be removed from the test tube with tweezers and transferred to a block bowl filled with diluted alcohol (isoprophyl alcohol or ethanol, 70% dilution).
PIC 9 – 10: Now you can remove the spermathecae at its base from the genital plate where it is connected to the genital plate, with the help of two dissecting needles, by fixing the genital plate with one dissecting needle and carefully removing the spermathecae from the genital plate by "scratching" it of with the other needle.
PIC 11 – 12: Once the spermathecae has been fully macerated and the examination is complete, the spermatheca is transferred to a genital tube. The genitalia micro vials known from entomology or the PCR tubes from genetics are suitable for this. The genital tube is then placed in the container with the preserved tarantula.
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