Caryl P. Haskins

Pheidole Megacephala and Iridomyrmex Humilis in Bermuda-Equilibrium or Slow Replacement?

Ants which actively extent their ranges and displace long—established populations of indigenous species on a world scale are limited to relatively few species. Two of the most striking are Pheidole megacephala and Iridomyrmex humilis. The former expanded its range from its original supposed home in middle Africa during the last century, displacing native species on a vast scale from Australia and Japan to the West Indies and Florida. Beginning somewhat later, Iridomyrmex humilis spread from western South America in a similar fashion and likewise attained a worldwide distribution. Its habitat preferences bring it into direct competition with Pheidole. During the second half of the nineteenth century its is known to have replaced Pheidole in Madeira, where Pheidole itself had earlier replaced the native ant fauna. Nothing is known in detail however, of the pattern of this replacement. Pheidole megacephala is known to have occupied Bermuda by the beginning of the present century, and largely replaced the native ant fauna. In 1957 it was observed by the authors that Iridomyrmex humilis had been introduced into Bermuda. This introduction, paralleling that in Madeira almost a century earlier, offers an excellent opportunity for a detailed analysis of the pattern by which one aggressive species of worldwide distribution may replace or coexist with another equally aggressive in an environment eminently suited to both, and in which there is evidently considerable competition for identical microhabitats. The present paper summarizes the result of two detailed surveys of the distribution of colonies of P. megacephala and I. humilis in Bermuda, made in 1959 and 1963. They evidence a gradual extension of the range of I. humilis at the expense of P. megacephala in a characteristic pattern. It is hoped that other workers will be encouraged to undertake further surveys of this change as it proceeds.

Stabilised heterozygosis of supergenes mediating certain Y-linked colour patterns in populations of Lebistes Reticulatus

Stabilised heterozygosis of supergenes mediating certain Y-linked colour patterns in populations of Lebistes Reticulatus

THE INHERITANCE OF CERTAIN COLOR PATTERNS IN WILD POPULATIONS OF LEBISTES RETICULATUS IN TRINIDAD

Pronounced sexual dimorphism of both form and color is characteristic of a number of viviparous teleost fishes of the subfamily Poeciliinae. The condition is perhaps most pronounced in several small related tropical forms, such as Micropoecilia branneri Eigenmann, Micropoecilia parae Eigenmann, Micropoecilia bifurca Eigenmann, and Lebistes reticulatus (Peters), all native to northeastern South America and two to adjacent Caribbean islands, which have, been included by Hubbs (1926) in the tribe Poeciliini. Among these small, largely surface-feeding, viviparous top-minnows the females are characteristically of generalized form and of an unspecialized, gray coloration, with very little body marking in the genus Micropoecilia and with none whatever in Lebistes save the characteristic reticulation. By contrast, the males of these species are brilliantly and characteristically colored and exhibit pronounced and species-specific patterns of courtship and mating behavior. In the genus Micropoecilia, the male color patterns within a single species may show decided variation over a wide geographic range, but they are normally quite constant in populations occupying many square miles of territory. Thus, for example, the males of Micropoecilia parae show an essentially constant color pattern throughout the very numerous populations which inhabit the lagoons and brackish coastal streams and ditches of the islands of Trinidad and Tobago. It is not known how the male color patterns are inherited in the genus Micropoecilia. In Lebistes, as in Micropoecilia, the males are small relative to the females, are of pronouncedly different form, and are of brilliant coloration. But the male color patterns, far from being constant within a given population even of restricted scope, are highly variable-so much so that, under natural conditions, it is difficult to find two individuals which exhibit even approximately similar patterns. Indeed, the males of Lebistes form one of the most highly polymorphic color series known in nature, in sharp contrast to the monotonous phenotypic uniformity of the females. The inheritance of male color patterns in Lebistes has been studied by Schmidt (1920), by Blacher (1927, 1928), by Kirpichinikow (1935), and more extensively by Winge (1921, 1922a, 1922b, 1927, 1930, 1932, 1934) and Winge and Ditlevsen (1938, 1948), in a long series of interesting investigations. As a result of these it seems clear that in Lebistes the male is normally the heterogametic sex and inheritance is typically of the XY pattern. The sex-chromosomes, however, are relatively unspecialized and are not morphologically distinguishable either from one another or from the autosomes. Furthermore, sex determination clearly does not reside entirely with the sex-chromosomes. Normally functional XY females and XX males have been demonstrated by Winge. The haploid chromosome number for the species is 23. Although the males of Lebistes exhibit extreme color polymorphism in their total color patterns, even in restricted wild populations, it is possible to resolve these patterns into a number of components which show clear-cut unifactorial inheritance, together with a number of others

Notes on the method of colony foundation of the ponerine ant Amblyopone australis Erichson

The method of colony foundation among ants is of peculiar interest to the student of phylogeny and social evolution in the Formicidae. Alone among the Aculeates, the Formicidae constitute a group all the members of which are social in character and have no immediately obvious affiliations witlh solitary forms, save for evident general affinities with such solitary Vespoid groups as the Scoliidae, the Thynnidae, the Mutillidae, and the Myrmosidae. The brief period of colony foundation, therefore, when the fertile females of mnany ants undergo a more or less prolonged period of solitary existence, becomes of peculiar significance as possible evidence, through recapitulation, of the manner in which social life arose and evolved in the Formicidae.

Das Unbewußte und die Psychosen. Einige Überlegungen zur psychoanalytischen Theorie der Psychosen

In einem umfassenden Uberblick legt der Autor die unterschiedlichen Konzepte des Unbewusten in der Psychoanalyse und in den Neurowissenschaften dar. Er unterscheidet drei Arten des Unbewusten: das Unbewuste bei Freud, bei M. Klein und bei Bion. Beim dynamischen Unbewusten Freuds, das bei der Neurosenbildung wirksam ist, uberwiegt die Verdrangung, aber auch andere Abwehrstrategien wie Verleugung oder Verneinung spielen eine Rolle; dieses Unbewuste erfordert die genetische Rekonstruktion. Das von M. Klein konzipierte Unbewuste setzt sich aus unbewusten Phantasien und der Spaltung der inneren Objekte, der Projektion und der Introjektion zusammen; der Analytiker wird zum Empfanger der projizierten und abgespaltenen Anteile, so das in der Behandlung dem Hier und Jetzt mehr Bedeutung zukommt. Die dritte Form des Unbewusten, das emotionale Unbewuste, das bei Psychosen und psychischen Storungen traumatischen Ursprungs relevant ist, wird von Bion und von den Neurowissenschaften beschrieben. Es handelt sich hierbei um eine seelische Funktion, die bei der Verarbeitung von Gedanken und Traumen bedeutsam ist, deren das Subjekt jedoch nicht gewahr wird; es erkennt lediglich derenResultat. Der Analytiker fungiert als Container, der die nicht-verbale und nicht wahrgenommene Kommunikation des Patienten aufnimmt und einer Transformation unterzieht. Anhand zweier Falldarstellungen erlautert der Autor den Umgang mit dem emotionalen Unbewusten.

Electrophoretic Analysis of Muscle Proteins in Several Groups of Poeciliid Fishes Especially the Genus Mollienesia

The water-soluble fraction from whole muscle protein in twenty species of poeciliid fishes representing eight genera and four tribes of the Poeciliidae has been studied by paper electrophoresis. Special attention was paid to the genus Mollienesia, particularly to the morphologically polytypic species M. sphenops. In the electrophoretic work a Spinco Durrumtype electrophoretic cell was used, with a sodium potassium phosphate buffer. The procedure was derived from that described by Hamoir (1951, 1955), Connell (1953, 1954), and also of Block, Durrum, and Zweig (1958). It was found possible to obtain constant, marked, and reproducible differences between various tribes and genera. Moreover, species could be differentiated within a single genus, Mollienesia. Finally, within the single polytypic species M. sphenops geographically isolated populations could be distinguished. The implications of the method for investigations in the taxonomy of the Poeciliidae are discussed. More especially, the implications for the study of evolution among geographically isolated populations of a single species, as well as for the investigations of balanced biochemical polymorphism within single panmictic populations, are considered. Further work is in progress.

Electron Bombardment of Biological Materials. I. An Electron Tube for the Production of Homogeneous Beams of Cathode Rays from One to Fifteen Kilovolts

An apparatus for the bombardment of small samples with electrons of 1 to 15 electron kilovolts energy has been developed and used. Special features render it particularly suited to a study of those biological materials which can tolerate high vacuum. The details of the construction and operation of the tube and of auxiliary apparatus are described.

Society and Scientific Research

“In the society of scientists each man, by the process of exploring for the truth, has earned a dignity more profound than his doctrine. A true society is sustained by the sense of human dignity…. This is why, at bottom, the society of scientists is more important than their discoveries. What science has to teach us here is not its techniques but its spirit: the irresistible need to explore.”J. BRONOWSKI-Science and Human Values

Organization of Research Establishments

The Organization of Research EstablishmentsEdited by Sir John Cockcroft. Pp. 275 + 4 plates. (London: Cambridge University Press, 1965.) 63s. net; 11.50 dollars.

Electrical Bombardment of Biological Materials II. An Electron Tube for the Production of Homogeneous Beams of Cathode Rays from Ten to One Hundred Kilovolts

An apparatus is described for irradiation of biological and chemical materials in vacuum with electron beams of intensities varying between 10−6 and 10−10 coulomb per square centimeter and of energies ranging between 10 and 100 kv. The beam can be easily adjusted and scanned for homogeneity. Through an arrangement of stops, a large number of targets can be conveniently irradiated in a relatively short period.