Final answer:
If two heterozygous moths (Ss) mate, 50% of their offspring would not be stealthy.
Step-by-step explanation:
In this scenario, if two heterozygous moths (Ss) mate, the offspring would inherit the alleles from both parents. The gene for stealthiness is represented by the dominant allele (S) and the non-stealthy trait is represented by the recessive allele (s). The Punnett square can be used to determine the expected ratio of offspring.
The Punnett square for this cross would be:
+---+---+
| S | s |
+---+---+
| S | SS | Ss |
+---+---+
| s | Ss | ss |
+---+---+
From the Punnett square, we can see that 50% of the offspring would be stealthy (SS) and 50% would be non-stealthy (Ss). Therefore, 50% of the offspring would not be stealthy.