Only positive m is allowed (here mutation introduces a bias towards m=0.5)

L=4
Sexual selection
32_600_0.0025_0.1   32_600_0.01_0.1   32_600_0.0025_0.2

L=8
Assortative mating (almost no variation)
32_600_0.0025_0.1   32_600_0.0025_0.2   32_600_0.01_0.1   32_600_0.01_0.2
Sexual selection (divergence with sigma_a=0.1, variation with sigma_a=0.2)
32_600_0.0025_0.1   32_600_0.0025_0.2   32_600_0.01_0.1   32_600_0.01_0.2


Symmetric preference function (-1<=m<=1, m=0.0 is random mating)
L=8
Assortative mating (no variation)
32_600_0.0025_0.1

Sexual selection
24_500_0.0025_0.1   24_600_0.0025_0.1   32_500_0.0025_0.1   32_600_0.0025_0.1 (23/30 cases with |m|>0.5)
                                                                                                      32_600_0.0025_0.15  (3/15 cases with |m|>0.5)
24_500_0.0025_0.2   24_600_0.0025_0.2   32_500_0.0025_02    32_600_0.0025_0.2  (0/15 cases with |m|>0.5)

                                                                                                     32_600_0.01_0.1  (15/15 cases with |m|>0.5; only once 4 species)
                                                                                                     32_600_0.01_0.15 (5/15 cases with |m|>0.5)
                                                                                                     32_600_0.01_0.2  (3/15 cases with |m|>0.5)

not much speciation in 24_500
max 2 species in 24_600; divergence in sigma_a=0.1, variation in sigma_a=0.2

variation, no divergence in 32 with sigma_a=0.2

Linear gradient in the frequency of theta_2=1 in 32_600_0.0025_0.1
               30 runs      _slope=0.0 (same as 32_600_0.0025_0.1 above;  12 cases with 2 "ecological" species; 18 cases with 4 eco-species)  T=68435 (+/-28600)
               15 runs      _slope=0.25   (always 4 eco-species)    average time to m=0.5 is T=75107 (+/-28088)
               15 runs      _slope=0.5       T=56800 (+/-23198)
               15 runs      _slope_0.75      T=57000 (+/-13996)
               15 runs      _slope=1.0       T=72733  (+/-23327)

Linear gradient in the frequency of theta_2=1 in 32_600_0.0025_0.15
               15 runs      _slope=0.0 (same as 32_600_0.0025_0.15 above)  3/15 cases with |m|>0.5; 
               15 runs      _slope=0.25   5/15 cases with |m|>0.5
               15 runs      _slope=0.5     4/15 cases with |m|>0.5
               15 runs      _slope_0.75    1/15 cases with |m|>0.5
               15 runs      _slope=1.0      6/15 cases with |m|>0.5