Sexual isolation between Drosophila melanogaster females and D. simulans males. II. Influence of female receptivity on hybridization

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 334-339 ◽  
Author(s):  
Maria C. Carracedo ◽  
P. Casares ◽  
E. San Miguel
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Age Differences ◽  
Sexual Maturity ◽  
Sexual Isolation ◽  
Female Receptivity ◽  
Male And Female ◽  
Allopatric Populations ◽  
Selection For ◽  
Main Factor

Hybridization between Drosophila melanogaster females and D. simulans males was measured in sympatric and allopatric populations of these sibling species by means of nonchoice tests. Greater sexual isolation was found in allopatric populations over sympatric ones. Notable age differences at which females reached sexual maturity were detected in the D. melanogaster populations. Females with an earlier sexual maturity also showed greater receptivity. Remarkably, female receptivity was the main factor accounting for frequency of hybridization. The role that both male and female mate propensities and discrimination abilities play in natural selection for sexual isolation is discussed. Key words: sexual isolation, Drosophila, female receptivity, hybridization.

Multiple sire mating in swine; evidence of natural selection for mating efficiency

1961 ◽  
Vol 56 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Lavon J. Sumption
Keyword(s):  
Natural Selection ◽  
Mating Behaviour ◽  
Animal Breeding ◽  
Evolutionary Significance ◽  
Mating Frequency ◽  
Combined Effects ◽  
Male And Female ◽  
Female Mating ◽  
Mating Efficiency ◽  
Selection For

Evidence of natural selection for certain aspects of mating efficiency in swine are advanced based on preliminary studies with thirty-one sires, fiftyeight dams and their progeny. Selective fertilization was conclusively demonstrated. Variations in male and female mating behaviour were sufficiently large to indicate considerable non-randomness of mating frequency under the conditions of multiple sire mating (i.e. group exposure of dams to selected sires). The combined effects of the separate phenomena of selective fertilization and mating behaviour are discussed in relation to their evolutionary significance in animal breeding.

A Shape to Die for?

2021 ◽  
pp. 481-510
Author(s):  
Graham Mitchell
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Surface Water ◽  
Alternative Hypothesis ◽  
Natural Habitat ◽  
Large Body ◽  
Male And Female ◽  
Large Size ◽  
Selection For ◽  
Competition For Resources

The product of natural selection over at least 15 million years is the elongated, slender shape of giraffes that fits the natural habitat giraffes now occupy. What selection pressures operated to produce their shape? Their shape is partly the product of gravity and could have been an accidental by-product of selection for a large body mass and the protection from predation that large size brings, but the prevailing explanation is that their shape confers a browsing advantage. Preferred browse is concentrated at a height easily reached by giraffes but not by other browsers and natural selection would have favored those giraffes that could reach it. An alternative hypothesis is that their shape confers thermoregulatory benefits in addition to improved vigilance. Another hypothesis is that a long neck evolved to counter long legs allowing giraffes to drink surface water. An attractive hypothesis is that their shape is a product of ‘runaway’ sexual selection by females for males with long heavy necks, but analysis of this hypothesis has shown that the morphology of male and female giraffe does not differ. Nevertheless, all these possibilities could have contributed. A consequence of selection for their shape is over-specialization: giraffes seem to be inextricably dependent on a narrow diet, a diet that is subject to the vagaries of climate and competition for resources. The greatest threat to their survival is, therefore, their shape.

GENETIC HOMEOSTASIS IN DROSOPHILA MELANOGASTER

1969 ◽  
Vol 11 (2) ◽  
pp. 414-425 ◽  
Author(s):  
P. D. Walton
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Selection ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
The Other ◽  
Diallel Crosses ◽  
Additive Component ◽  
Selection For ◽  
Genetic Homeostasis

The literature provides three explanations of the way in which genetic homeostasis functions. An attempt was made to determine which of these was applicable to the changes which occurred when selection for geotaxis was relaxed in certain strains of Drosophila melonogaster. The strains, for which selection stopped, were divided into two parts and generations were advanced in two environments. One was the same as that in which selection had been made and the other was new. When selection was relaxed strains reverted to a mean geotactic score close to that of the populations from which they had been selected. This change was more rapid in the new environment. A series of diallel crosses compared strains for which selection was continued with those for which it was relaxed. An analysis of the components of genetic variation showed that the principle change that had taken place was in the additive component of genetic variation. It was concluded that genetic homeostasis resulted from the action of natural selection on additive genetic variance, a conclusion which is in agreement with one of the three current hypotheses.

Selection for Delayed Senescence in Drosophila melanogaster

2001 ◽  
Vol 2001 (1) ◽  
Author(s):  
Leo S. Luckinbill ◽  
Robert Arking ◽  
Michael J. Clare ◽  
William C. Cirocco ◽  
Steven A. Buck
Keyword(s):  
Drosophila Melanogaster ◽  
Life History ◽  
Natural Selection ◽  
Life Span ◽  
Genetic Control ◽  
Mode Of Action ◽  
Aging Process ◽  
Delayed Senescence ◽  
Selection For ◽  
Early Fecundity

Although theories of the evolution of senescence differ in the mode of action by which genes are thought to control the aging process, they all view the rate of senescence as an adaptable feature of life history and therefore modifiable by natural selection. Tests of theory, however, have generally yielded mixed results. The life-span of Drosophila melanogaster increased strongly in populations selected for late reproduction in these experiments. Delayed senescence was accompanied by a reduced early fecundity, suggesting pleiotropic genetic control of the aging process. Reproduced by permission. Leo S. Luckinbill, Robert Arking, Michael J. Clare, William C. Cirocco, Steven A. Buck, Selection for Delayed Senescence in Drosophila melanogaster. Evolution 38 , 996-1003 (1984).

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