Appendix 1
Let Nf and Nm be the number of female and male adults respectively. Then, the effective
population size is known as (e.g. (Hartl, Clark, 1989) page 86):
Ne 
4N f Nm
N
f
 Nm 
(1)
The total number of adults (census size) Nc=2Nf if a balanced sex ratio is assumed.
Let nf fec be the number of females sired by each most successful males and x the number of
most successful males (other males do not mate successfully), then:
x
Nf
nf fec

Nc
2nf fec
(2)
Combining (1) and (2) gives:
4
Ne 
N c2
nf fec

N  N c (1  nf fec )
 c
2nf fec
2 
Nc Nc
2nf fec 2
 Nc

 2nf
fec

(3)
For all nffec>0 and all Nc>0 equation (3) reduces to:
Ne 
2 Nc
1  nf fec
(4)
Then if Nc is known, we can extract nffec as:
nf fec 
2Nc
1
Ne
(5)
or if nffec is known, we can extract Nc as:
Nc 
1 nf fec
2
Ne
(6)