The marriage market refers to the sum of male and female mate choices (Lamanna and Riedmann 1991).
We calculated the male proportion of fetal deaths by dividing the number of male fetal deaths by the sum of male and female fetal deaths.
A GLM was also used to compare the total proportion of time the parents spent at the nest, i.e. the sum of male-only, female-only and joint nest attendance, between the two species.
If we assigned a binary code to the allele effect (strong = 1 and weak = 0), then the sex of this PSD species could be predicted by simply comparing the sum of male to female alleles.
The expected proportions were assumed to follow the Hardy Weinberg law and were calculated from the allele frequencies observed in the entire population (sum of male and female individuals).
Here, we follow the DHS specifications of modern methods; they are the sum of male and female sterilization, intrauterine devices (IUDs), oral contraceptive pills, injectables, implants, male and female condoms, diaphragm/foam/jelly, the lactational amenorrhea method (LAM), the Standard Days Method (SDM), and "other" modern methods.
Peak swarm size and the cumulative male numbers (the sum of all males observed every 3 minutes throughout the duration of the swarm) were highly correlated.
Discrepancy between total numbers and sum ups of male and female numbers are due to the missing data.
Thus, we assumed that females actively prefer males the nuptial coloration of which reflects at wavelength that they detect most easily, and that females detect male signals easily if the sum of the male's reflectance × the female's sensitivity is large.
In sum, selection of male return migrants has worsened over time.
