Guess i read it wrong, you were talking about a killer BEL so i guess i missed the 2nd parent also having a spider gene. but good luck telling if you have a killerbee BEL lol.
spiders a bad one to calculate anyways because we really don't know whats going on with it, if it is leathal, then you would have a 33% chance for normal 66% for spider, since the homozygous form dies. if its a more complicated gene than we think and for some reason it only exists in het form, then it would be 25/75