Hubert Markl

Maternal care in house mice

SummaryThis paper analyzes the flexibility of maternal care in wild house mice (Mus domesticus) under different reproductive conditions in the laboratory. All maternal activities were both qualitatively and quantitatively analyzed over a period of 28 days after birth of a litter. The standard behavior of a lactating house mouse with 7–8 young can be described as follows: During days 1–16 the offspring fully depend on the mother for nutrition. Due to rapid growth of the litter, the energetic demands of lactation reach a peak for the female during days 13–16. During days 17–22, the weaning period, the young begin to eat solid food. This period is characterized by behaviors that indicate different interests of the mother and offspring, and thus the existence of a parent-offspring conflict sensu Trivers (1974). Resting alone and remaining far from the litter indicate the females interest in avoiding the offsprings demands, which are expressed in frequent attempts to initiate sucking. There is no aggression towards the young during weaning. House mice are weaned at 23 days. The relationship between mother and young appears free of conflict after weaning. Nursing is replaced by resting with body contact, but the offspring do not try to suck. The following results suggest that during the weaning period the offspring do not get more milk than corresponds to the maternal optimum—despite their frequent sucking attempts:(a) When the mother is simultaneously lactating and pregnant, offspring are smaller at weaning than under standard conditions. (b) Small litters are weaned earlier than large ones. Despite a longer nursing period, offspring from large litters are lighter at weaning than those from small ones. (c) Under high energy demand, as after postpartum mating and with large litters, females wean their young at a body weight which corresponds to the earliest physiologically possible state of independence.Parity of the female has no effect on maternal activities, nor has the presence of the father. In the latter case, however, offspring are less often left alone and unprotected.Females seem to adjust their investment according to the body weight of the progeny by delaying or advancing the date of weaning (Table 2). This behavior allows the production of the largest possible number of offspring that can be raised to a minimal physiological threshold corresponding to a body weight of approximately 9 g. Such flexibility in parental care may enhance maternal fitness under different and unpredictable environmental conditions.

Recruitment and food-retrieving behavior in Novomessor (Formicidae, Hymenoptera) - II. Vibration signals

Summary1.In this article, we report the communicative effect of stridulation signals in Novomessor cockerelli and N. albisetosus during foraging2.The structure of the stridulatory organ and the main characteristics of airborne and substrate-borne stridulation signals are described.3.The stridulation signals are not perceived by the ants over any appreciable distance. However, workers that contact an object transmitting stridulatory vibrations stay at this probe significantly longer than at a nonvibrating control probe.4.An information transfer analysis was performed by comparing the probabilities of occurrence of different behavioral acts in workers both before and after contacting either a ‘stridulatory’ test probe or a ‘silent’ control probe. Stridulation did not affect the behavior of food carriers; diggers that carried debris from the nest were slightly but significantly influenced; but a remarkable change did occur in the probabilities of behavioral acts by scout ants.5.Stridulation alone does not release a specific behavioral response but rather enhances more or less a change to different behavioral activities in workers.6.In a series of field experiments, it was shown that a prey object too large to be retrieved by one ant stimulates the finder ant to stridulate. It was further demonstrated that the vibrational signals received by a second ant that also contacted a prey enhance the release of chemical short-range recruitment signals by this ant. In our experiments, the facilitating effect of stridulation on chemical recruitment led to a time advance of 1–2 min in both the recruitment of workers and in the retrieval of large prey objects by groups of foragers. It has been demonstrated that the rapid group retrieval of large prey objects enables Novomessor workers to successfully compete with mass-recruiting ant species such as Solenopsis and Iridomyrmex.7.Significantly more digging is only released at a ‘stridulatory’ test probe if the probe is offered very close to a nest entrance.8.Stridulation in ants seems to be a mechanism for modulating the state of readiness of receivers to react to other stimuli (modulatory communication). The stridulation signal adjusts the distribution of the worker force to a given situation and to group needs in a graded fashion, but does not by itself release specific behavioral reactions. This phenomenon is compared with similar functions in other communication systems of complex animal societies.

Mating behavior and sound production in harvester ants (Pogonomyrmex, Formicidae)

Summary1.Stridulation sound production was investigated in sexuals of the harvester antsPogonomyrmex barbatus, P. rugosus andP. maricopa of the SW United States during preparation and take-off for nuptial flight, as well as during mate selection, copulation and postcopulatory behavior on the mating leks, and competition in the process of colony foundation.2.The structures of the stridulatory organs and the characteristics of air-borne and of substrate-borne signals of the three species are described (Tables I and II). There are no prominent interspecies differences in the distress signals.3.Stridulatory communication is not involved in the control of preflight warm-up and take-off for the nuptial flight. Further, it does not play a role in the selection of species and sex of the mates, or in the competition among males for females.4.Females of all species stridulate regularly when prevented by males from leaving the lek after several copulations. It is assumed that this «female liberation signal» communicates the females non-receptivity to approaching males and makes them let the female go.5.Founding queens stridulate regularly when competing for founding burrows, especially if physical fights are involved. Nevertheless, our experimental results do not substantiate a communicatory function for this behavior.Zusammenfassung1.Die Schallerzeugung durch Stridulation wurde an Geschlechtstieren der ErnteameisenPogonomyrmex barbatus, P. rugosus undP. maricopa aus dem SW der USA sowohl während der Vorbereitung zum Hochzeitsflug und beim Abflug, als auch bei der Geschlechtspartnerauswahl, der Kopulation und dem postkopulatorischen Verhalten auf den Paarungsarenen und während Konkurrenzaggression bei der Koloniegründung untersucht.2.Der Bau des Stridulationsorgans und die Eigenschaften der in Luft bzw im Substrat fortgeleiteten Signale der drei Arten werden beschrieben (Tab. I und II). Es gibt keine hervorstechenden interspezifischen Unterschiede zwischen den Abwehrsignalen.3.Stridulationskommunikation spielt keine Rolle bei der Kontrolle des Aufwärmens vor dem Flug oder des Abflugs zum Hochzeitsflug und genausowenig bei der Erkennung von Art oder Geschlecht eines Partners oder in der Konkurrenz der Männchen um die Weibchen.4.Weibchen aller untersuchten Arten stridulieren regelmäßig, wenn Männchen sie daran hindern, nach mehreren Kopulationen die Balzarena zu verlassen. Es wird angenommen, daß dieses «weibliche Befreiungssignal» Männchen bei der Annäherung die mangelnde Kopulationsbereitschaft der Weibchen anzeigt und sie dazu bringt, von den Weibchen abzulassen.5.Gründerweibchen stridulieren regelmässig, wenn sie um Gründungskammern konkurrieren, besonders wenn es dabei zum Kampf kommt. Nichtsdestoweniger erlauben unsere Experimentalbefunde nicht den Schluß, daß diesem Verhalten dabei eine Verständigungsfunktion zukommt.

Who owns the human genome? What can ownership mean with respect to genes?

The progressive elucidation of the structure of the human genome with the subsequent use of this information for various purposes, many of which will be of commercial value, raises questions about the ownership of the information. This article points out some of problems of defining the genome as property and explores the relevance of the usual criteria of patent law to this new situation.

Challenges of Globalization for Science and Research

Globalization challenges all social systems in all nations – how then could it spare the sciences? A question however is: what is new about this? Has not this happened throughout history? And a further question is: what is special for the sciences in all this? Although globalization may not be a new thing, with a population of over 6 billion people its impact becomes all-pervasive and its consequences are severe. It is not only that science enters into all cultures, whether advanced or less developed. Humans also come to depend on it more and more, and this for better or for worse. Science is literally vital to human beings in that they have come to rely upon it for food, potable water, energy, and security in their environment, or in old age. All people, in ever-increasing numbers, therefore have to be instructed in science so that they become aware of how dependent they are from the continuing progress in science, and to what extent innovation and advantages in economic competition depend upon their abilities to make the best use of science. In fact, science has become so powerful an influence on all ways of life that it can no longer be left to the scientists alone. Their power has to be constrained by morals and by laws, and it becomes inevitable that economists and lawyers, and above all politicians intrude upon what the scientists often regard as their exclusive turf. This may in time be the biggest challenge of the globalization of science.

Jewish intellectual life and German scientific culture during the Weimar period: the case of the Kaiser Wilhelm Society

Weimar Germany was a great period in scientific development in which Jews played a prominent role. However, Nazi anti-Jewish policies led to the dismissal of many staff members and directors of the institutes of the Kaiser Wilhelm Society, who were forced to go abroad. In their new environment they became major leaders in science – notably in the new branches such as molecular biology – with a continuing loss to Germany.

The future of nature

Through the evolution of the conscious mind in the human species, nature became aware of itself and can thus, for the first time in more than three billion years of natural evolution, influence and even, to some degree, take control of its own future development according to intentional goals. Since these goals are, at the same time, inevitably our own wishful visions, our species becomes not only natures managing agent but also morally responsible for the future of nature, including our own future. This essay tries to draw conclusions from evolutionary, ecological, cultural, anthropological and moral perspectives. It not only asks about the place of human beings in nature as some kind of alien intruder, but seeks to understand human cultural evolution as part of nature, as the consequent continuation of natural evolution having become not only self-organized but self-guided and responsibly self-controlled.

Constraints on human behavior and the biological nature of man

The contribution of biology to a better understanding of human legal behavior seems severely limited for three reasons: (1) Since laws are cognitive constructs of the human mind which must be verbalized to become effective, man is the only species in which legal behavior can be studied. All inferences from animal behavior studies and from evolutionary considerations are highly speculative with respect to human legal behavior. (2) In the ontogenetic development of human behavior there is adaptation of the behavior to the environment, including culture. There seems no reliable procedure to factor out their relative contribution, particularly since genetic adaptation can be easily phenocopied. Therefore it is only rarely possible to separate a ‘biological’ component of human behavior from a ‘cultural’ one. (3) Most theories pertaining to the evolution of behavior in animals (and more so in man) are ‘weak’ theories with some retrodictive but little predictive power; they allow us to define probable modes for behavioral averages but say little about the behavior of individuals, which is at issue in legal considerations.

Misunderstanding and Misuse of Darwinism

The reason why I wavered a bit with this topic is that, after all, it has to do with Darwin, after a great Darwin year, as seen by a German scientist. Not that Darwin was very adept in German: Gregor Mendel’s ‘ Versuche uber Pflanzenhybriden ’ (Experiments on Plant Hybrids) was said to have stayed uncut and probably unread on his shelf, which is why he never got it right with heredity in his life – only Gregory Bateson, Ronald A. Fisher, and JBS Haldane, together with Sewall Wright merged evolution with genetics. But Darwin taught us, nevertheless, in essence why the single human species shows such tremendous ethnic diversity, which impresses us above all through a diversity of languages – up to 7000 altogether – and among them, as a consequence, also German, my mother tongue, and English. It would thus have been a truly Darwinian message, if I had written this article in German. I would have called that the discommunication function of the many different languages in humans, which would have been a most significant message of cultural evolution, indeed. I finally decided to overcome the desire to demonstrate so bluntly what cultural evolution is all about, or rather to show that nowadays, with global cultural progress, ‘the world is flat’ indeed – even linguistically. The real sign of its ‘flatness’ is that English is used everywhere, even if Thomas L. Friedman may not have noticed this sign. But I will also come back to that later, when I hope to show how Darwinian principles connect both natural and cultural evolution, and how they first have been widely misunderstood as to their true meaning, and then have been terribly misused – although more so by culturalists, or some self-proclaimed ‘humanists’, rather than by biologists – or at least most of them. Let me, however, quickly add a remark on human languages. That languages even influence our brains and our thinking, that is: how we see the world, has first been remarked upon by Wilhelm von Humboldt and later, more extensively so, by Benjamin Whorf. It has recently been shown by neural imaging – for instance by Angela Friederici – that one’s native language, first as learned from one’s mother and from those around us when we are babies, later from one’s community of speakers, can deeply impinge on a baby’s brain development and stay imprinted in it throughout life, even if language is, of course, learned and not fully genetically preformed. This shows once more how deep the biological roots are that ground our cultures, according to truly Darwinian principles, even if these cultures are completely learned.

Basic research for the future of Europe

Scientific research, a common heritage that laid the foundations of the modern world, stands as a unifying principle of Europe and is, among other values, a binding bridge to all nations. Being an inalienable part of humanity, the striving after knowledge embodied in scientific research is a necessary precondition if mankind is to handle successfully the consequences of globalized economies, a still growing world population with increasing life expectancies and the need for sustainable development. The European Science Foundation, with its flexible structure for promoting European cooperation in research can play an active part in supporting national governments and the European Union in formulating research policies and educational standards and in intensifying exchange and cooperation with the non-European countries.