The distribution and movements of two stoat populations were studied by capture-recapture and tracking in the Swiss Jura Mountains. On the Brévine area in summer 1977 the population was at a high density phase and evenly distributed. A well established intrasexual territorial system was observed, with a high degree of sedentarity in adults. During the decline and the following phase of scarcity, the stoats were progressively restricted to a peat-bog area and the territorial system broke down. The adult males became transient and a high degree of dispersal was recorded among the juveniles. On the Val de Ruz area, the population was fairly stable and the stoats had home ranges and movements adapted to habitat characteristics. Adult males in March-April and juveniles moved around considerably. These aspects of the spatio-temporal distribution pattern of Mustela erminea are discussed in relation to the main factors affecting it, such as population density, habitat, sex and age, activity, and seasons.
Using male mice doubly heterozygous for pairs of Robertsonian translocation chromosomes that have one arm in common, mouse embryos monosomic for 11 of the 19 autosomes have been generated. All of these monosomies result in death prior to or during the implantation period, with only rare survivors being detected 6 days after fertilization. For some of the monosomies the onset of lethality can be detected during the third or fourth day of development, but others do not begin to die until sometime after the late blastocyst stage on day 4. Retardation of development, as revealed by decreased cell numbers, is often detectable prior to or after the onset of the lethal period. The period during which death occurs may spread over several days and does not coincide with any of the developmental landmarks of the pre- or peri-implantation period. Genetic factors that may affect the rate of cellular proliferation or other aspects of embryonic development appear to play an important role in determining exactly when individual monosomies result in death. The universal early lethality of the autosomal monosomies leads to the conclusion that a large number of loci scattered over all of the autosomes are involved in processes that are so concentration dependent that a 50% reduction is sufficient to produce very serious consequences.
The polecat (Mustela putorius L.) in western Switzerland. -13 individuals were caught between 1979 and 1983. One rabid animal died, the others were marked and released.Other evidences for the presence of the polecat in western Switzerland, such as hunting reports are quoted.This species, though not abundant in the study areas, does not seem endangered. It is no more hunted in Switzerland since 1979 and even since 1972 in the Cantons Neuchâtel and Vaud. The diet is based mainly on Microtines. The cranial nematode, Skrjabingylus nasicola was identified in all examined individuals.
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