"Resistance leads to self-destruction": how an (a)political strategy helped Karl von Frisch succeed during the Nazi era.

Karl von Frisch, one of the leading zoologists of the twentieth century and co-founder of the Journal of Comparative Physiology A, has been frequently portrayed as an opponent of the Nazi regime because he, as a 'quarter-Jew,' faced the threat of forced retirement from his position as a professor at the University of Munich during the Third Reich. However, doubts about an active opposition role have surfaced in recent years. A litmus test for assessing the validity of this notion is provided by our discovery that four of the six core members of the anti-Nazi resistance group 'White Rose'-Sophie Scholl, Hans Scholl, Christoph Probst, and Alexander Schmorell-were his students. When they were arrested, sentenced to death, and executed, he seemed to ignore this historic event, both during and after World War II-in line with his belief that resistance leads to self-destruction, and research can flourish only by ignoring what happens around oneself. On the other hand, this seemingly apolitical attitude did not prevent him from making use of politics when it served his interests. Such actions included his (pseudo-)scientific justification of forced sterilization of people suffering from hereditary disorders during the Third Reich and his praise of the Nazi government's efforts to "keep races pure." As unsettling as these and some other political views and actions of Karl von Frisch are, they enabled him to carry out several critical pieces of his research agenda during the Third Reich, which three decades later earned him a Nobel Prize.

In memoriam: Thomas Cavalier-Smith (1942-2021).

Thomas Cavalier-Smith, born in London, U.K., on October 21, 1942, was a Professor of Evolutionary Biology in the Department of Zoology at the University of Oxford at the time of his death on March 19, 2021. Credited with at least 235 research works and over 20,000 citations, Cavalier-Smith was a well-known and widely respected scientist who took a bold and detailed approach to understanding major transitions in evolution, including the role of endosymbiosis. He was noted for his willingness to question theories and constantly accumulate and evaluate data, motivated by science for the sake of science. This paper reviews Thomas Cavalier-Smith's major accomplishments, examines his theoretical approaches, and provides highlights from the "Tree of Life Symposium" sponsored by the International Society of Protistologists (ISOP) and the International Society of Evolutionary Protistology (ISEP) on June 21, 2021, to celebrate Tom's life and work.

Zoology of Fishes.

The Zoological Society of Japan is one of the longest-standing scientific societies in Japan, and it has been publishing a unique prestigious international journal in zoology, Zoological Science, for a long period of time since its foundation in 1984 as the continuation of Zoological Magazine (1888-1983) and Annotationes Zoologicae Japonenses (1897-1983). One of the most salient features of the Society and the Journal may be the variety of species of animals used in the studies by the members of the society and the authors of the journal. Among various animal species, fish may have contributed to almost all disciplines of presentations and publications, including behavioral biology, biochemistry, cell biology, developmental biology, diversity and evolution, ecology, endocrinology, genetics, immunology, morphology, neurobiology, phylogeny, reproductive biology, and taxonomy. Owing to the recent advancement of modern molecular genetic methods in biology, not a few fish species have contributed to various research disciplines in zoological science as model animals. The present Special Issue includes various kinds of such studies in zoological science by taking advantage of a variety of fish species, which are contributed by authors of various generations ranging from junior to senior zoologists.

The impact of prolonged frozen storage on the preparation quality of bird skins and skeletons in zoological collections.

Specimens from zoological collections play a pivotal role in improving scientific knowledge in many natural science disciplines. To guarantee an optimum state of conservation and ensure their usefulness, the preparation process employed is crucial. Skins and skeletons are key elements in vertebrate scientific collections and, ideally, are prepared from recently deceased animals; however, specimens are often stored in a frozen state for a long time (years) prior to preparation. Whether the duration of this frozen state has a deleterious effect on preparation quality has rarely been studied. The main objective of this study was thus to contribute towards research into zoological preparation by testing to see whether prolonged frozen storage hinders the preparation of bird skins and skeletons. We used the common buzzard (Buteo buteo) and the barn owl (Tyto alba) as biological models. Our results showed that long-term frozen storage led to weight loss, bone marrow acidification and solidification, and hampered skin preparation. The necropsy affected weight loss and decreased the skin tear resistance, probably due to tissue dehydration. Thus, prolonged frozen storage appears to have a harmful effect on the preparation quality of vertebrate specimens. Since frozen storage could ultimately have an impact on the conservation and scientific use of museum specimens, practices should be implemented to minimise the amount of time specimens are frozen or to mitigate any detrimental effects. More importance should be attached to research on zoological preparation since it is fundamental for optimising the quality, conservation status, and value of museum collections.

Implementing long-term baselines into primate tool-use studies.

Studies on primate tool-use often involve the use of baseline conditions, as they allow for the examination of any differences in the subjects' behavior before and after the introduction of a tool-use task. While these baseline conditions can be powerful for identifying the relative contributions of individual and social learning for the acquisition of tool-use behaviors in naïve (usually captive) subjects, many have criticized them for being too short, and not allowing enough time for the behavior to develop spontaneously. Furthermore, some wild tool-use behaviors such as chimpanzee nut-cracking require animals to manipulate and familiarize themselves with the materials of the behavior within a "sensitive learning period" before it develops later on in life. One solution to this problem is to implement long-term baselines, in which, with collaboration with zoological institutions, the materials of the behavior are left in the enclosure for an extended period. The keepers would then be asked not to demonstrate or train the animals in the target behavior, but to report back to the researchers if they observe the behavior emerge during this extended period. Alongside keeper reports, video cameras could be installed in the enclosure to minimize the chance of false negatives and to allow for coding and inter-rater reliability to be carried out on the videos. These long-term baselines therefore provide extended enrichment opportunities for the animals, alongside allowing the zoological institution to publicize their involvement with the study and guests to observe animals interacting with different testing apparatuses and tools. Finally, long-term baselines can provide invaluable insight on the individual and social learning abilities of primates as well as the potential development stages and sensitive learning periods required for specific behaviors.

An automated aquatic rack system for rearing marine invertebrates.

BACKGROUND: One hundred years ago, marine organisms were the dominant systems for the study of developmental biology. The challenges in rearing these organisms outside of a marine setting ultimately contributed to a shift towards work on a smaller number of so-called model systems. Those animals are typically non-marine organisms with advantages afforded by short life cycles, high fecundity, and relative ease in laboratory culture. However, a full understanding of biodiversity, evolution, and anthropogenic effects on biological systems requires a broader survey of development in the animal kingdom. To this day, marine organisms remain relatively understudied, particularly the members of the Lophotrochozoa (Spiralia), which include well over one third of the metazoan phyla (such as the annelids, mollusks, flatworms) and exhibit a tremendous diversity of body plans and developmental modes. To facilitate studies of this group, we have previously described the development and culture of one lophotrochozoan representative, the slipper snail Crepidula atrasolea, which is easy to rear in recirculating marine aquaria. Lab-based culture and rearing of larger populations of animals remain a general challenge for many marine organisms, particularly for inland laboratories. RESULTS: Here, we describe the development of an automated marine aquatic rack system for the high-density culture of marine species, which is particularly well suited for rearing filter-feeding animals. Based on existing freshwater recirculating aquatic rack systems, our system is specific to the needs of marine organisms and incorporates robust filtration measures to eliminate wastes, reducing the need for regular water changes. In addition, this system incorporates sensors and associated equipment for automated assessment and adjustment of water quality. An automated feeding system permits precise delivery of liquid food (e.g., phytoplankton) throughout the day, mimicking real-life feeding conditions that contribute to increased growth rates and fecundity. CONCLUSION: This automated system makes laboratory culture of marine animals feasible for both large and small research groups, significantly reducing the time, labor, and overall costs needed to rear these organisms.

From Entomological Research to Culturing Tissues: Aron Moscona's Investigative Pathway.

Aron Arthur Moscona (1921-2009) was an Israeli-American developmental biologist whose name is associated with research on cell interactions during embryonic development. His appearance on the international scene dates back to a paper published in 1952, while he was working, together with his wife Haya Sobel Moscona, at the Strangeways Research Laboratory of Cambridge. Together they demonstrated that cells from previously dissociated chick tissues undergo histiotypical and organotypical aggregation in vitro. From 1952 to 1997, Moscona focused his research on cell recognition mechanisms, ultimately demonstrating the role of transmembrane proteins in cellular adhesiveness, tissue segregation, and organ tridimensional assemblage during development. However, who was Aron Moscona before 1952 and what brought him to developmental biology? A Polish Jew who immigrated to Mandatory Palestine in 1933, Moscona belonged to the first generation of biologists formed in the newly established Zoology Department of the Hebrew University. With a particular focus on the Israeli context, the paper reconstructs the evolution of Moscona's scientific thought by emphasizing the cultural and experimental context of his training and early research at the Hebrew University. The aim is to investigate how local scientific traditions influenced Moscona's eventual research as well as enabled the relevant experimental innovation he contributed to the field of developmental biology and pathology. The paper can be read both as a scientific biography of Aron Moscona and as a preliminary contribution to the historiography of embryology in the Mandatory Palestine/Israeli context.

Looking for Mimicry in a Snake Assemblage Using Deep Learning.

Batesian mimicry is a canonical example of evolution by natural selection, popularized by highly colorful species resembling unrelated models with astonishing precision. However, Batesian mimicry could also occur in inconspicuous species and rely on subtle resemblance. Although potentially widespread, such instances have been rarely investigated, such that the real frequency of Batesian mimicry has remained largely unknown. To fill this gap, we developed a new approach using deep learning to quantify the visual resemblance between putative mimics and models from photographs. We applied this method to Western Palearctic snakes. Potential nonvenomous mimics were revealed by an excess of resemblance to sympatric venomous snakes compared with random expectations. We found that 8% of the nonvenomous species were potential mimics, although they resembled their models imperfectly. This study is the first to quantify the frequency of Batesian mimicry in a whole community of vertebrates, and it shows that even concealed species can act as potential models. Our approach should prove useful for detecting mimicry in other communities, and more generally it highlights the benefits of deep learning for quantitative studies of phenotypic resemblance.

On Growth and Form in context - an interview with Matthew Jarron.

D'Arcy Thompson was born in 1860, trained in Edinburgh and Cambridge, and held positions in Dundee and St Andrews, where he worked until his death in 1948. On Growth and Form, his classic work on the mathematical patterns and physical rules underlying biological forms, was first published in 1917. To learn more about the book's context, we met Matthew Jarron, Curator of Museum Services at the University of Dundee, in the University's D'Arcy Thompson Zoology Museum. Surrounded by specimens, many of which were collected by Thompson himself, we discussed the legacy of On Growth and Form and the life of the man behind it.

Infrared thermography cannot be used to approximate core body temperature in wild primates.

Understanding the physiological processes that underpin primate performance is key if we are to assess how a primate might respond when navigating new and changing environments. Given the connection between a mammal's ability to thermoregulate and the changing demands of its thermal environment, increasing attention is being devoted to the study of thermoregulatory processes as a means to assess primate performance. Infrared thermography can be used to record the body surface temperatures of free-ranging animals. However, some uncertainty remains as to how these measurements can be used to approximate core body temperature. Here, we use data collected from wild vervet monkeys (Chlorocebus pygerythrus) to examine the relationship between infrared body surface temperature, core body (intra-abdominal) temperature, and local climate, to determine to what extent surface temperatures reflect core body temperature. While we report a positive association between surface and core body temperature-a finding that has previously been used to justify the use of surface temperature measurements as a proxy for core temperature regulation-when we controlled for the effect of the local climate in our analyses, this relationship was no longer observed. That is, body surface temperatures were solely predicted by local climate, and not core body temperatures, suggesting that surface temperatures tell us more about the environment a primate is in, and less about the thermal status of its body core in that environment. Despite the advantages of a noninvasive means to detect and record animal temperatures, infrared thermography alone cannot be used to approximate core body temperature in wild primates.

Researchers' ethical concerns regarding habituating wild-nonhuman primates and perceived ethical duties to their subjects: Results of an online survey.

While the process of habituation is essential for researchers to observe primates in their natural habitats, ethical dilemmas may arise from its consequences. We collected data from 286 participants via an online survey to investigate: (a) how primatologists perceive their ethical duties toward their subjects; (b) the extent to which primatologists are concerned about the potential ethical consequences of habituation; and (c) the methods primatologists use to reduce potential harms caused by habituation. Overall, primatologists felt an extremely strong duty to mitigate harms that they may cause (e.g., to not stress individuals during observation, treat injuries, and reunite separated individuals) and expressed very high concern for habituation's potential to increase the vulnerability of their subjects to poaching and disease transfer. Ratings for those items were so high that they could not be included in subsequent exploratory factor analyses that were designed to reveal constructs underlying respondents' ratings of their ethical duties and concerns. Factor analysis of ratings of ethical duties revealed that primatologists reported a strong duty to mitigate harms caused by other humans and a lower perceived duty to mitigate naturally occurring harmful events. Factor analysis on ethical concern ratings revealed that respondents were concerned about harms during the habituation process, the presence of unhabituated behavior after habituation had been established, and indirect harms of habituation. Concerns for unhabituated behavior and indirect harms were rated slightly higher than concern for harms during the habituation process. To mitigate potential harms, primatologists primarily reported engaging in strategies to reduce stress in their subjects. Our findings reveal a disconnect between primatologists' ratings of their ethical concerns and their reported mitigation practices that may, in part, stem from gaps in knowledge about the true impacts of habituation. We suggest areas of discussion and research in the field necessary to address those gaps.