As a consequence of the differences in their survival ability, black snails produce on average 0.3 offspring, brown snails produce 0.6 offspring, and white snails produce 1.2 offspring.
(black snails; produce; ) (brown snails; produce; 0.6 offspring; T:0.3 offspring) (white snails; produce; 1.2 offspring)
black snails brown snails white snails
produce produce produce
0.6 offspring T:0.3 offspring
1.2 offspring