You could go a bit further, and do spider x other morph, and see if fewer or more spiders were produced in combonation with other morphs. That way things like bumblebees would be counted as a spider, since they carry the spider in combo with pastel.

Always neat to see the tweaking of real life vs the math numbers. Once in a while you can get a little surprise! If you gather the numbers for 10,000 spider clutches each of male spider to female normal, and female spider to male normal... would the odds be 45%/65%.... or would it swing to the 50/50?

Interesting things to ponder.