The contributions of genotype and sex to variation in mating behaviour between geographical subspecies of the bank vole (Clethrionomys glareolus scheber)

The sexual behaviour of bank voles from the mainland of Great Britain, and from the island of Skomer, differs in a number of respects. Voles from the mainland population show in general greater sexual activity. These variations may be understood as adaptations to ecological differences, particularly in population density. The reciprocal hybrids resemble the mainland population in a number of aspects of their mating behaviour. The possible evolutionary importance of this dominance is discussed. The behaviour of the bank vole is put into the perspective of generalizations made about other mammals. The separate influence of the male and of the female on quantitative variation between the two forms was investigated by studying mating between members of different populations. Some aspects of mating behaviour are shown to be due primarily to the male, others primarily to the female and others to the particular combinations involved. This situation is discussed in relation to the separate action of natural selection on members of each sex.     

Effect of Ca2+-antagonists on virally-induced cell-permeability changes

Sendai virus-mediated permeability changes in cells are affected by extracellular Ca2+ or Mn2+ as follows: the lag period to onset of permeability changes is lengthened and the subsequent extent of leakage is reduced. Drugs that block Ca2+ action in excitable cells, such as verapamil and prenylamine, and drugs that inhibit the action of calmodulin, such as trifluoperazine and R24571, have an effect opposite to that of Ca2+: lag is shortened and extent of leakage is increased. The concentration at which either type of drug shows 50% of maximal effect is similar to the concentration at which 50% of binding by drug to calmodulin is achieved. It is concluded that calmodulin may be involved in protecting cells against virally-mediated membrane damage; alternatively the action of calmodulin-binding drugs may not be as specific as currently thought.