biologe

Blog and online journal with editorial content about science, art and nature.

Monat: November, 2020

Linyphiid spider visits much bigger snail and bites into mucus

During a photo shooting with a specimen of the snail Arianta arbustorum in an evening outdoors in urban park Rehberge in Berlin with artificial light from an extra lamp and camera LED light, a tiny spider of Linyphiidae (seemingly Bolyphantes sp., may be still a juvenile) appeared unexpectedly and walked seemingly targeted to the snail’s head, which was partly retracted into its shell, and stayed there for about 3 minutes, biting repeatedly into the snail’s mucus and remained subsequently each time for seconds in that position. In between it skillfully and repeatedly rearranged the positions of its legs, presumably to be not in danger to remain stuck.

While doing so, it sometimes lifted legs, when not needed, in the air, may be to reduce that way the probability to remain stuck. After about 3 minutes the spider left its position around the snail-head mucus and walked partly sidewards to the top of the shell, where it carefully cleaned its legs from remaining mucus. Due to the difficult light conditions and the unexpected spider visit, I was in this short time unable to move the camera closer to the spider (would have been technically possible, when more time and more light). Thus-close-ups with a high magnification in my video were only due to digital magnifications out of the original 4K footage. Only one biting action could be clearly documented as video file. The same short scene is in my video three times repeated to exemplify that behavior.

Spider visiting a snail, in order to incorporate mucus? Berlin May 2020, copyrights Stefan F. Wirth

The last repetition is additionally modified into slow motion. There was furthermore no video footage of legs adjusted in the air. Thus the corresponding short scene is one of numerous photos, which I captured before filming. It is unknown to me, what the purpose of the spider’s behavior was. I also did so far not find any scientific publication mentioning tiny spiders visiting much bigger snails on purpose. It looked to me as if the spider would incorporate mucus or moisture or other components excreted by the snail. I do not know, whether such a spider behavior happens regularly or at least occasionally, as I only have this one observation. I would exclude the possibility that the spider was disturbed by my photo activities in its web may be in the adjacent meadow, tried to flee and accidentally landed on the snail and just observed this unusual surrounding with its mouthparts. All looked too much like a targeted behavior with even specific behavioral adaptations. There is generally not much known about spider and snail interactions. The scientists Nyffeler and Symondson (Bern, Switzerland) published in 2001 about malacophagy in the sense of gastropod feeding by spiders (Ecological Entomology 26). But that paper deals about bigger and even big spiders feeding on snails of adequate size, which is unlike the size relations in my observed case.

It is not trivial for a spider to incorporate anything from snail mucus, as this very sticky slime acts besides other functions as defense mechanism for the gastropod. In that context the above mentioned authors cite Tretzel (1961) by mentioning that mucus production of gastropods seems to have no deterring effect on some spiders. The question then is the efficiency of spider enzymes against snail tissue, a topic, about which I did not do more literature research. According to the above mentioned authors, moisture can in malacophagous spiders be an important factor, as gastropod bodies consist to a high percentage of water. They refer to Lain (1982), who published about New Zealand mygalomorph spiders. In the case of my observation it would eventually be of interest, referring to the context above, that also gastropod mucus contains a high water percentage. More observations such as mine would be needed to find out, whether the behavior of the linyphiid spider on a much bigger slug is a specific behavior or not.

Berlin, May-November 2020, urban park Rehberge, copyrights Stefan F. Wirth

Der Doktortitel der Franziska Giffey/ the doctoral degree of Franziska Giffey (SPD)

On purpose falsifications of doctoral theses are unfortunately quite common in the world of German leading politicians (SPD and CDU). They either performed plagiarisms or other illegal methods to be honored with an undeserved academic title in order to push their later political careers. Since years online communities check doctor-theses of celebrities and often discovered inconsistencies or plagiarisms. Many titles subsequently were denied.

A recent case is the federal minister of family affairs Franziska Giffey (SPD). She already longer time ago was discovered having too many citations without labellings in her thesis. The responsible university, FU Berlin, reacted with a reprimand. As groups thought this not being sufficient, the university announced to start a new examination procedure, of course with a risk for Giffey to loose her title. She seemingly (my own interpretation) tries now to stop or influence that procedure by officially stating that she would renounce any further use of her title forever. According to my knowledge this is academically no solution. One has a doctoral title or one doesn’t. Thus the procedure by the university needs to be continued.

I think it’s a wrong opinion that illegal methods in academic times would not at all affect the later politician career. According to my conviction, a criminal instinct is necessary to falsify that document, for which other invest much life energy. These remarkable numbers of illegally received doctor titles in politicians from CDU/CSU and SPD additionally reduce the reputation and worth of legal doctoral theses of other academics. The willingness to falsify indicates a character issue that I think also effects the recent politician work of the corresponding persons remarkably. If Mrs. Giffey looses her doctoral degree, I would recommend her to step down from her political position immediately.

Gefälschte oder abgekupferte Doktortitel sind unter Politikern der SPD und CDU/ CSU nur allzu häufig geworden. Zahlreiche höher rangige Politiker bewiesen bereits in ihrer akademischen Zeit eine beachtliche Bereitschaft zur Fälschung, was ich mir nur durch ausgeprägte Skrupellosigkeit, ja sogar einen gewissen kriminellen Instinkt erklären kann. Während andere beachtliche Lebensenergie in ihre Doktorarbeiten investieren, wird er woanders mit illegitimen Mitteln, ja illegalen Mitteln, geradezu unaufwendig abgeerntet. Das beflügelt die spätere politische Karriere, aber zeigt auch, mit was für einer Person welcher moralischer Festigung man es zu tun hat.

Ein solcher Fall ist möglicher Weise Familienministerin Franziska Giffey. Der Plagiatvorwurf ist schon etwas älter, wie auch die Reaktion der zuständigen Universität, FU Berlin, die nach Überprüfung damals lediglich mit einer Rüge reagierte. Diese Vorgehensweise ist nun in Kritik geraten, weswegen die Universität ein neuerliches Prüfungsverfahren angekündigt hat. Heute lässt die Ministerin wissen, sie verzichte freiwillig auf die künftige Verwendung ihres Doktortitels. Ist dies ein Versuch, das Verfahren der FU, das mit gewisser Wahrscheinichkeit zu einer Aberkennung führt, zu stoppen oder zu beeinflussen? Es geht nicht um Versprechungen zur Nutzung des Titels, es geht darum, ob man ihn hat oder nicht. Das Verfahren muss daher fortgesetzt werden. Im Falle einer Aberkennung wünsche ich mir einen Rücktritt der Politikerin von allen politischen Ämtern. Es ist aus meiner Sicht nämlich nicht wahr, dass die Skrupellosigkeit gepaart mit möglicher Weise kriminellem Instinkt während der Dissertation zu trennen ist von der Persönlichkeit im späteren politischen Amt. Was soll da der trennende Faktor sein? Wenn man die Erfahrung gemacht hat, durch Betrug zum Erfolg zu gelangen, warum sollte die betroffene Person plötzlich ehrbar, glaubwürdig und legal sowie mit moralischen Werten in ihrem politischen Amt agieren?

Doctoral certification from a university in Berlin, Promotionszeugnis einer Berliner Universität (Symbolbild)

Berlin, November 2020, copyrights Stefan F. Wirth