I. Michael Lerner

Self-Elimination of Tribolium castaneum Following Xenocide of T. confusum

Studies of competition between synthetic strains of T. castaneum (CS) and T. confusum (CF) in corn alone and corn supplemented by yeast reveal that under the temperature and humidity conditions of the experiment CS eliminates CF in both media. While the surviving population of CS remains at a high level in corn when supplemented by yeast, it declines in number when kept in corn alone. Suspicions that this decline results from nutritional deficiencies in the case of T. castaneum are confirmed by experiments in which the two species reared in corn are fed eggs of the other species, and others in which T. castaneum reared in corn or corn with yeast is supplied pupae of T. confusum. It is concluded that these nutritional deficiencies lead T. castaneum to practice xenocide. Since in this way T. castaneum is eliminating the more efficient vehicle of conversion of corn into nutritional requirements essential to it, T. castaneum is also practicing unwitting near-suicide.

Genetic Variation and Indeterminism in Interspecific Competition

Lerner and Dempster (1962) have recently suggested that much of the apparent indeterminacy of outcome in competition experiments involving the two species of flour beetles, Tribolium confusum and T. castaneum (see, for instance, Neyman, Park and Scott, 1956) is the result of genetic heterogeneity of the founders of the competing populations. In support of this hypothesis they presented data which indicated that the more the genetic variation is reduced by inbreeding, the more determinate the outcome of competition becomes. More recent experiments (connected with the competition experiments previously reported only by the fact that the same material was used) conducted by one of us (P.S.D.) have unexpectedly revealed evidence in confirmation of the hypothesis of Lerner and Dempster. The full experimental details will be reported elsewhere. Here only those aspects which are germane to the question of indeterminism will be mentioned. They relate to selection for fast developmental rate (days to pupation) in a number of populations of Tribolium.

Competition between Tribolium species (Coleoptera, Tenebrionidae) on several diets

Abstract Competition studies between T. castaneum and T. confusum have been carried out on whole wheat flour and on cornmeal (maizemeal) supplemented with tryptophan and yeast, singly and in combination. The hypothesis that the success of T. castaneum in eliminating T. confusum on media which are inadequate to maintain at a high density level populations of T. castaneum in single species cultures, lies in its tendency to supply itself with essential nutrients by cannibalizing T. confusum has received partial confirmation. Tryptophan is one of the deficient factors in the cornmeal diet but it is by no means certain that it is the only possible corrective supplement. Various aspects of the study suggest the necessity of investigating more fully the nutritional requirements and their genetic bases if an understanding of the nature of competitive ability in Tribolium is to be attained.

The Inheritance of Egg Production in the Domestic Fowl

THE problem of inheritance of egg production in the domestic fowl has attracted considerable attention, particularly because of the practical implications of the subject. As is the case with many other characters of economic import, the progress towards the solution of the problem has been rather slow. In fact, to date only two significant landmarks in the history of investigations in this field can be pointed out. The first of these is a series of papers by Pearl (1909 et seq.) which constituted the initial fruitful investigation of the question, while the second is the methodological innovation introduced by Goodale (1918). The voluminous literature on the subject built up since videe Jull, 1940), deals with many important points, but practically in all cases they are elaborations and refinements of what may be called the Goodale principle.

Buffered Genotypes and Improvement in Egg Production

It is suggested that genetic variation in egg production depends to a degree on buffering capacity. Observations in support of this hypothesis are briefly reviewed.

Natural Selection and Egg Size in Poultry

Experimental evidence is given for the operation of natural selection for egg size in populations of domestic fowl. As a rule the counter-force of artificial selection in commercial flocks maintains average egg size above the optimum for reproduction.

Ethics and the new biology

Publisher Summary This chapter presents the ethics and moral issues that are raised by the new biology. The ethical and moral guidelines of the past have developed partly on the basis of democratic pressures; partly on the basis of service to special interests, including those of the class of priests; partly as a result of impact of individual leaders, whose motivations in turn may have been based on various rational and sometimes irrational but functional considerations. For the majority of people in the past, the standards of behaviour, of action and of social interaction, though having evolved just as other social processes and institutions, were codified by authority. The chapter reviews the manipulation of individual genotypes and barely possible genes; the prospects of cloning; the putting of human chromosomes into apes for research or possibly various nefarious purposes; the production of test-tube or surrogate mother babies(prenatal adoption); and multiparental mosaics. The furthering of esthetic ideals of the possibilities of self-actualization, the fulfilment of mans potential for expressing himself both as an individual and as a member of a group, the development of loyalties to increasingly more inclusive entities from self to family to parish to country to the world at large are attainable with the conquest over hunger, disease, toil, hatred, and war, which technology can make possible. The ethics of the decision-making in the contemporary world are not clear, but the development of an effective and a just machinery for this process as it concerns individuals and society should have a high place on mankinds agenda.

THE ALPHA AND OMEGA OF CURRENT EVOLUTIONARY THOUGHT

The consummation of a cataract of Darwinian festivities and commemorations held in the course of 1958 and 1959 in many lands and on all continents (with the possible exception of Antarctica) was reached in the week-long Centennial Celebration at the University of Chicago in November of the latter year. Two volumes 1 of the proceedings are now available, and a third, containing papers on science and religion, the proces-verbaux of five panel discussions and a general index to the whole series, is, at the time of writing, still to come (the set will then be available for

Heritability of Threshold Characters.

25.00). It might have been expected that, after the inundation of ceremonies, exhibitions, symposia, colloquia, seminars, lectures, broadcasts, critiques, reviews, appreciations, discussions and evaluations of Darwin, his predecessors, his followers, his work and his influence, the final jubilee examination of Evolution After Darwin, could be an anticlimax, especially, since most of those who have something worthwhile to contribute to the subject already had had their say (or usually, says). Indeed, G. G. Simpson, himself one of the most profound and brilliant of the performers on the Darwin circuit, has, in an address delivered at the end of the two years of the miscellaneous observances, expressed surfeit, approaching boredom, with the whole business. Such expectation, happily, is completely unfounded. The organizers of the Centennial displayed both imagination and ingenuity in the range of matters covered and in the selection of contributors. The result is a prodigious compendium and a distinguished exhibit of the alpha and omega (the tangible whole of science rather than the occult one of Teilhard de Chardin) of evolutionary thinking prevalent in the middle of the twentieth century. The celebrants at the Darwinian bicentenary will, no doubt, find many of the opinions now expressed no longer tenable, much of the present emphasis misplaced in the light of their superior knowledge, some of the current evidence misinterpreted. They may smile at some visionary pronouncements, they may be amused by what, no doubt, will seem to them to be oversimplifications. They will search and find in these