Female Mating Counter-adaptations

2021 ◽  
pp. 3024-3024
Keyword(s):  
Female Mating

scholarly journals BREED AND SEX EFFECTS ON THE RELATIONSHIP BETWEEN WEIGHT AND FATNESS IN LACOMBE AND YORKSHIRE SWINE AND THEIR RECIPROCAL CROSSES

1965 ◽  
Vol 45 (1) ◽  
pp. 33-36
Author(s):  
G. W. Rahnefeld
Keyword(s):  
Body Weight ◽  
Sex Differences ◽  
Regression Coefficients ◽  
Average Depth ◽  
Constant Weight ◽  
Reciprocal Crosses ◽  
Sex Effects ◽  
Female Mating ◽  
The Mean ◽  
The Relationship

The relationship between thickness of fat measured at the shoulder, last rib, and loin of live pigs and market weight (86.2 to 95.2 kg) was studied in 1596 pigs from the Lacombe and Yorkshire breeds and their reciprocal crosses. No significant breed or sex differences were found in the proportion of fat at the three sites. Breed and sex differences were evident in the average depth of fat. The regression coefficients for the mean of three fat measurements on market weight were.016 ±.003,.019 ±.007, and.017 ±.004 for Lacombe males, barrows, and females respectively;.039 ±.002,.036 ±.005, and.041 ±.001 for Yorkshire males, barrows and females respectively;.027 ±.005 and.029 ±.004 for barrows and females from the Lacombe male × Yorkshire female mating; and.023 ±.007 and.021 ±.009 for barrows and females from the Yorkshire male × Lacombe female mating. Comparisons between animals measured at a relatively constant weight should be made after the fat measurement is adjusted for variations in body weight. The results of this study indicate that separate corrections should be applied for each breed. Separate corrections for sexes within breeds do not appear warranted.

Sperm Competition and the Dynamics of X Chromosome Drive: Stability and Extinction

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1721-1731 ◽  
Author(s):  
Jesse E Taylor ◽  
John Jaenike
Keyword(s):  
Sex Ratio ◽  
Sperm Competition ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Basin Of Attraction ◽  
Male Mating ◽  
Male And Female ◽  
Mating Rate ◽  
Female Mating ◽  
Balanced Polymorphism

AbstractSeveral empirical studies of sperm competition in populations polymorphic for a driving X chromosome have revealed that Sex-ratio males (those carrying a driving X) are at a disadvantage relative to Standard males. Because the frequency of the driving X chromosome determines the population-level sex ratio and thus alters male and female mating rates, the evolutionary consequences of sperm competition for sex chromosome meiotic drive are subtle. As the SR allele increases in frequency, the ratio of females to males also increases, causing an increase in the male mating rate and a decrease in the female mating rate. While the former change may exacerbate the disadvantage of Sex-ratio males during sperm competition, the latter change decreases the incidence of sperm competition within the population. We analyze a model of the effects of sperm competition on a driving X chromosome and show that these opposing trends in male and female mating rates can result in two coexisting locally stable equilibria, one corresponding to a balanced polymorphism of the SR and ST alleles and the second to fixation of the ST allele. Stochastic fluctuations of either the population sex ratio or the SR frequency can then drive the population away from the balanced polymorphism and into the basin of attraction for the second equilibrium, resulting in fixation of the SR allele and extinction of the population.

scholarly journals Natural female mating rate maximizes hatchling size in a marine invertebrate

2008 ◽  
Vol 77 (4) ◽  
pp. 696-701 ◽  
Author(s):  
D. Sprenger ◽  
J. Faber ◽  
N. K. Michiels ◽  
N. Anthes
Keyword(s):  
Marine Invertebrate ◽  
Mating Rate ◽  
Female Mating ◽  
Hatchling Size

COUPLING BEHAVIOUR OF THE MIGRATORY GRASSHOPPER, MELANOPLUS SANGUINIPES (ORTHOPTERA: ACRIDIDAE)

1972 ◽  
Vol 104 (6) ◽  
pp. 873-879 ◽  
Author(s):  
R. Pickford ◽  
C. Gillott
Keyword(s):  
Sexual Activity ◽  
Melanoplus Sanguinipes ◽  
Male And Female ◽  
Female Mating ◽  
Unfavourable Weather ◽  
High Level

AbstractThe mechanics of coupling in Melanoplus sanguinipes (Fabr.) are described and differences between some species of Acrididae discussed. A high level of coupling activity was revealed with the most active male and female mating 56 and 46 times, respectively. In addition, multiple daily matings, to a maximum of five, were common. The majority of copulations occurred during the morning in both laboratory and field; however, in the latter, unfavourable weather restricted sexual activity. Coupling did not appear to occur at random; significant preferences were shown by certain males for certain females.

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