biologe

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

Tag: science

Germany on the way from a part-lockdown to a full-lockdown?

Leaders of the German national subsidiaries and the federal government, above all the chancellor Merkel, ask for stricter contact limitations. Although the current conditions in form of a part-lockdown as reaction to increasing numbers of covid-19-infections throughout Germany restrict numbers of people, who are allowed to meet up inside or outside as well as the numbers of households, to which they belong, already remarkably. All public places for socializing and cultural activities are closed, also sport clubs, public swimming trainings or outdoor sport activities in greater groups are impossible. That means, bars, cafés, restaurants are closed. Theaters and opera houses as well. Especially „smaller“ stage artists suffer existentially.

Only the german football (soccer) is still omni-present in the news reports. I don’t know why. Seemingly their games can happen under limited circumstances. I am not interested in football at all. It is also not football, which is since the beginning of the human evolution a major fundament of our societies, it’s art. Art is not only creativity, it also stands for legal criticism against all aspects of social and political interactions. Thus something important is missing. And private life? It is already in the recent part-lockdown harmed in a way, that acts against the human biology as social primates. Not only old people in retirement homes live almost under conditions of a dentation centre, also single-persons of all ages, living in smaller apartments, need to tolerate loneliness. The Homo sapiens is a social species, too much isolation can cause longtime-damages, emotionally, psychologically, in case of older people even physically. Not to forget those citizens without any kind of home. The many homeless people, especially in Berlin, are very sensible victims of recent restrictions. Are all these risks, the Germans actually are exposed to, worth to happen? I think yes, they are, if it is for a limited time and under circumstances, which do not cause more damages than the virus infections themselves. It is fact that the new corona virus can be harmful to people of all ages, especially when there are significant medical histories existing. But as all these sanctions represent limitations of our basic laws, it is important that all these limitations are reversed when the pandemic is over.

Critical questions are allowed. They are also important and necessary. And you even do not need to be a believer of modern religious movements like Qanon. I for example ask for the relevance of indirect contacts between individuals for the still too high infection numbers. When I see super markets, forcing their clients to use shopping baskets or trolleys without employees existing, who desinfect each of them before and after use, then I hear the virus clapping amused its non existing hands: „We couldn’t get you so far? Here we are, left behind from hundreds of people per day, who touched this basket or this trolley before!“ Are such contra- productive rules necessary, even when the argument is that baskets and cars force a proper distance between customers? Also in U-Bahn cars (subway etc.), trams or busses, an indirect virus transfer between passengers needs to be much better prevented . Shouldn’t it be possible to employ people, who permanently walk through the cars and desinfect seats and handrails whenever possible?

As a natural scientist and active researcher as well as reviewer for scientific journals I know that statistics generally bear many reasons for critical questions. It can easily happen that submitted natural-scientific papers in peer-review journals are rejected by the reviewers based on doubtful or insufficient or even wrong statistical methods. We read or hear in the news permanently about growing incidence numbers. Many people might think that these are given facts, about which questions or critical remarks are not appropriate or necessary. Based on the limited informations via the popular media, the following questions are very sure and from a scientific point of view of interest: How many people of a specific region, for example a district of Berlin, were tested and how many were not? In case of higher numbers of non-tested citizens, statistical means need to be used in order to extrapolate to the whole population of the corresponding region. It is important that a statistical variance within the tested people is guaranteed. There would for example be a lack of a sufficient variance, if it came out that specific genders or specific occupational groups had more reasons or even forces to participate test procedures than others. Statistical tests always have a defined probability of errors. But more and illegitime errors can for examples be added, when research institutions need to provide a defined high number of data in a defined period of time, especially when the procedure is well paid and „success“ thus economically important. According to my knowledge and experiences, scientific studies can only be finished, when they are finished. Evaluations in defined time periods with defined numbers of sample sizes are prone to error. I know from commercial institutions for market and opinion research that the time pressure is often or sometimes used for the disadvantage of a sufficient variation of test persons. Some facilitate their work by contacting such people for phone interviews, who’s telephone numbers were part of a commercial phone number trading. That means they buy existing phone numbers instead of generating them via a random number generator. Additionally/ or they facilitate statistical methods, which were developed to guarantee a variation of test persons. An example is the „Geburtstagsschlüssel (birthday key)“, which requires from the interviewer to strictly only talk to that person of a household, who was the last to have birthday or alternatively will be the next to celebrate it. If that person, so the rules, is not available, the interview cannot happen. Based on economic interests of the institutions and the time pressure, facilitated versions of the „birthday-key“ are sometimes used. Such as: asking for the birthday person in the household, and if the person is not available interviewing everybody available instead, or even leaving the birthday key completely out. Results of such „manipulated“ evaluations can be representative nevertheless. But they also might not be representative at all. There exist examples for extrapolations of upcoming electoral successes, being far removed from the real situations. What does all this have to do with evaluations about covid-19-infection numbers? I hope that independent sources regularly control the responsible research institutions regarding the proper use of statistical methods even under time pressure conditions.

In case it is made sure that indeed bars, restaurants, theaters and opera houses and not indirect contaminations elsewhere or statistical errors or manipulations cause the permanently high numbers of new infections everywhere in Germany, a total lockdown will be unavoidable. The German government and the federal state representatives will come together for further deliberations still before Christmas. This was announced in the news today. It is important that the decision for stricter measures need to take those groups of the German population under consideration, which might physically, psychologically or financially too much harmed by a full-lockdown over a longer period of time. It furthermore needs to be excluded that participating politicians have other motivations than protecting us from a pandemic virus, such as lust for power, interest in totalitarian experiments or a total lack of empathy.

Berlin, 08.12.2020, copyrights Stefan F. Wirth

Biodiversity research in the US, is the so called American Way always a good basis?

A collegue from the field of entomology recently wrote me his impressions about the situation of scientific fundings in the western world, as he travels around and stays with each of his feet in another country. He said that everybody knows about the importance of the biodiversity on earth and that consequently everybody agrees that research on the biodiversity deserves to be funded. But he continued that this does not mean that the same people would agree that biodiversity research requires experts and that experts would even need to be paid. Thus many of his former students in the US or Germany need to survive with temporary jobs other than their expertises would require.

But also an international unbalance of financial resources, available for fundamental research in entomology or for example acarology (my discipline) can lead to experts being sorted out, although they would be urgently needed. The focus, based on the considered eligibility of research, changed withing the last 25 years. As before Germany was a hotspot for high-quality research in the fields of evolutionary biology, systematics and biodiversity research, that focus of interest is now located in the USA. They invest more money into these sciences than all European countries together.

This can additionally have consequences for the quality of such kinds of research. It is no secret that the general educational level in the US is at least in some areas comparably low, many people don’t speak foreign languages, they often don’t travel abroad, and they live in midst of a mentality, which says „America first“. Biodiversity research would in the old German world of science regularly be connected with many „but consider that…“ conditions. The American way, in some cases, might want to have it easier. They might say: what’s the problem? What do they want to have? Yes, right, they want the numbers of all discovered species. They ask for numbers, thus we do our best to give them numbers, as fast as possible.

Some privileged US-researchers might even misuse their financial power to decide, who in other countries is and who is not. But I say in a rhetoric „you“: Use your fundings to involve as many suffering experts from abroad as possible, instead of center too much work and responsibility on yourself, you won’t have enough time due to too many species, which still need to be discovered and described.  Don’t work too fast and don’t risk to become too superficial. Each species deserves time. Share the work with others and make science benefit from the different kinds of backgrounds in different areas of the world.

 

Amsterdam_027

A mite of the Histiostomatidae, found in Amsterdam in its original substrate as example for the topic „Acarology“

 

All copyrights (also of SEM photo): Dr. rer. nat. Stefan F. Wirth, Berlin July 2020

Mite Histiostoma sachsi (Astigmata): Juvenile dispersal instar deutonymph and its orientation behavior

Some animals live in environments, where there is (almost) no light available. It makes no sense to see in the dark, but it is important for a specimen to know, where it actually is, where it is going to, whether there is enough food and what the conspecifics are doing. Predators need to be recognized in time, and a sexual partner must be found. There is also need for an efficient communication between specimens of a species. How can all this be performed by mites of the Astigmata, which usually live inside decomposing soil habitats in a more or less permanent darkness?

 

Olfactory sense organs in mites of the Histiostomatidae

 

Histiostoma sachsi (Histiostomatidae, Astigmata) is such a mite, living inside cow dung or compost. It might have a rudimentary ability for a light perception, but has not visible or functional eyes. It cannot produce any sounds. It can only feel and smell. Seemingly very limited abilities, but the contrary is fact: Due to evolution this mite is perfectly adapted to its life-style. It can feel objects by touching on them using its body setation (= body hairs). And it smells by means of very specialized body hairs, which are called solenidia and appear in different types, shapes and functions. These mites don’t smell on the level of us humans, which would be very insufficient. If at all, it should be compared with a dog. I am always fascinated when seeing blind dogs and how perfectly they can interact with their environment, despite their handicap. That’s may be how the efficiency of olfactory perception abilities of such a mite must be imagined. They do not only perceive scent particles from other animals, plants and soil components. Even olfactory signals from their conspecifics will be correctly and differentiatedly interpreted. And that not only marginally.  Olfactory signals represent indeed the major mode of their intraspecific communication.

 

Chemical communication of mites of the Histiostomatidae

 

Communication always requires contributions from both sides, a signal and an answer. These mites smell the signal of a conspecific using their solenidia, and they answer by the secretion of biochemical components. For these purposes, they possess a huge and complex gland system located on the upperside of their backs. Volatile excretions aggregate inside a big and rounded reservoir and finally leak to the outside via a pore, called oilgland opening. These gland systems are located symmetrically on both sides, each with one reservoir and one pore.

The meaning of the sent volatile message simply depends on the composition of the correspondingbiochemical components. Even diffferent stereochemical configurations of the same molecule can have different meanings. Citral for instance is a major component and has in different stereoisomers different functions. Such cummunicative volatile signals are usually named pheromones. And mites of the Histiostomatidae can indeed produce different kinds of pheromnes via the same gland system. Aggregation pheromones inform specimens about a suitable place to stay together with their conspecifics, for example due to a sufficient amount of food resources. Alarm pheromones solicit mites nearby to flee from an unpleasant situation. Sexual pheromones attract adult partners to each other in order to perform the mating procedure. But the gland secretions can even more. As allomones, they communicate with specimens of other species. They function as defenses against predators or other dangerous cohabitants.

 

Deutonymphs need to find a carrier for dispersal

 

Another form of communicative interspecific interactions is performed by a specific juvenile instar, the deutonymph. It looks morphologically quite different from all other instars (heteromorphic situation), does not need or possess a functional mouth, has a thicker cuticle as protection against drying out and a complex sucker organ on its underside in order to attach itself to an insect or another bigger arthropod. Deutonymphs of the astigmatid mites search for bigger carrier-arthropods to get carried from one habitat to another (dispersal strategy  is calledphoresy). While doing so, they again use their specifically modified leg setation (hairs) on the first pairs of legs to perceive scents for the detection of a suitable and passing by carrier. Basically it is still unknown, whether the term „communication“ is indeed appropriate in this context as we don’t know yet about a mutual interaction between deutonymphs and their carriers, before the phoretic ride begins.

 

 

Olfactory orientation of the deutonymph of Histiostoma sachsi, copyrights Stefan F. Wirth, February 2019.

 

Specific way of walking in deutonymphs

 

In detail, different kinds of behaviors can be observed in deutonymphs, when searching a carrier. The detailed behavioral patterns in this context can slightly differ between even closer related species. Deutonymphs of Histiostoma sachsi as all deutonymphs show a characteristic mode of walking, in which especially the first pair of legs plays an important role. During each step, performed by four pairs of legs, the first legs are lifted up much higher than all other hind legs. While doing so, they slightly tremble up and down. A behavior that mostly supports a better basic orientation inside a „jungle-„micro-landscape, being filled up with soil particles and decomposing plant tissues. But what H. sachsi deutonymphs additionally need in order to find their carriers is repeatedly to rest between the walking activities. Thus the first legs, which normally are still walking legs, are made free and that way available for the perception of carrier-scent-components only. These  namely are the legs that bear the highest densiy of solenidia.

 

Two different behavioral modes for an efficient orientation towards a carrier

 

Two different modes of resting with olfactory searching activities could be observed: In periodic intervals the deutonymph attached to the ground by using its sucking structures. They were then more or less laying on their entire undersides with only their forebodies slightly lifted up. By alternating moving the first legs up and down, olfactory information could be perceived from all directions without having the own body as a barrier to backwards. To improve its orientation situation, the deutonymph additionally turned on its own axis around, being stabilized by its sucking structures, which are flexible enough to follow these movements. When the deutonymph intended to continue its walk, it first needed to detach from the ground, which happened via muscle contractions that caused an abrupt detachment of the corresponding suckers. But main aim of the deutonymph is to find an elevated place, where the probability of a passing by carrier is especially high and from where a bigger insect (or other arthropod) can easier be ascended. There the second behavioral mode was performed. The deutonymph only fixed the edge of its hind body to the ground, again using the suckers on its underside, which are located close to this edge. This time the entire mite body stood in an upright position. The first legs again „waved“ alternating up and down and could under these especially elevated conditions even perceive scents from bigger distances. By occasionally slightly and alternating turning their upright bodies to both sides, olfactory information could be easier detected from all directions.

 

Carrier of H. sachsi still unknown

 

The frequency of such movements in mites increases typically as closer a suitable carrier approaches. But this was not yet observed or documented for Histiostoma sachsi. Its carrier inside the compost substrate is still unknown, which is why I so far could’t perform corresponding experiments. The species‘ describer, Scheucher (1957), found her mite specimens in cow dung and also didn’t identify the corresponding carriers there.

The observations presented in my video are part of my research project about morphologies and behaviors of deutonymphs in the Histiostomatidae.

 

Berlin, February 2019. All copyrights Stefan F. Wirth.