Article Navigation. Aggression of breeding eastern bluebirds S ialia sialis toward their mates and models of intraspecific and interspecific intruders. The influence of dominance rank on the reproductive success of female chimpanzees.
One-year old males averaged Are they primarily shaped by fecundity or survival selection i.
The form I males sexually mature will usually stay in form I throughout the winter and molt to form II the following spring. Adair Lora E. If, however, one of these mates is high quality and the other low quality, should we not also consider the former individual to have higher mating success than the latter?
Ecological relations of crawfishes of Illinois.
Austad SN. In most sexually reproducing species, the ratio tends to be That's a simple ratio, although it's also common to see it in terms of s. Just checking in. The sex ratio, as it naturally appears without too much human alteration, is generally assumed to be the natural balance that will best ensure a species' survival.
The incubation period, which is dependent on temperature, normally lasts for two to 20 weeks Pennak Multiple mating in a lekking bird—why do peahens mate with more than one male and with the same male more than once.
Although some evidence points to food as a source of female—female competition, other work advocates an offspring protection hypothesis Maestripieri ; Wolff and Peterson While quality is a more subtle measure of mating success than quantity, the critical condition for selection to favor female—female competition is a positive selection differential, even if the magnitude of the payoff in females is smaller than in males.