An informal account records the remaining traces of Tarkowski's research visits to the United Kingdom and France. The account has many authors and it should not be regarded as an exact history. The early 1960s began with the dramatic production of chimaeras at the University of Bangor and the long term exchange of information with Anne McLaren's Edinburgh laboratory. The techniques of parthenog...

S. A. S. BIRAJ MOHAN DAS GUPTA, Calcutta School of Tropical Medicine and Hygiene. A paper read at the Medical Research Section of the Indian Science Congress, Lucknow, January 1923. Now that the earlier views of Schaudinn (1902) on malarial relapse as being due to a production of merozoites by parthenogenesis on the part of the macrogametocytes,? (a process which, even if it existed, would be s...

vertebrates, are: (1) The abundant occurrence in nature of a form of demonstrated hybrid origin, having nearly all of the characteristies of a natural species; (2) the occurrence of a form as females only, over a wide portion of its range; (3) the consistent and abundant production of wholly female and purely matroclinous young; (4) apparent parthenogenesis in nature. CARL L. HUBBS LAURA C. HUB...

Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. T...

In 1861, Charles Darwin wrote "We do not even in the least know the final cause of sexuality; why new beings should be produced by the union of the two sexual elements, instead of by a process of parthenogenesis". It was hardly possible to begin to answer this question at that time, in view of the contemporary lack of knowledge of genetics and cell biology. Since then, research into the cellula...

Theory predicts that sexual reproduction is difficult to maintain if asexuality is an option, yet sex is very common. To understand why, it is important to pay attention to repeatably occurring conditions that favour transitions to, or persistence of, asexuality. Geographic parthenogenesis is a term that has been applied to describe a large variety of patterns where sexual and related asexual f...

Parthenogenetic eusocial insects (among ants and bees) combine two lingering and exciting issues: the evolution of sex on the one hand, and the evolution of social behaviour on the other hand, undoubtedly the "Royal Couple" for evolutionists! Important insights may arise from the comparative study of these few species displaying different and sometimes extraordinary social structure. Notably, n...