A researcher studies a population of speckled beetles (Diaperis maculata) in two habitats: woodland and grassland. The elytra (wing case) pattern in this species is either spotted or striped; this characteristic is controlled by a single gene with two alleles. The numbers of individuals of each phenotype in each habitat are:
Woodland: 156 spotted, 44 striped Grassland: 72 spotted, 68 striped
The researcher also measured the number of eggs laid per female beetle over a breeding season in each habitat. The results are summarised below:
Woodland: mean number of eggs = 28.4, standard deviation = 5.2, sample size = 30 Grassland: mean number of eggs = 24.1, standard deviation = 4.8, sample size = 30
Explain the type of variation shown by the elytra pattern and by the egg count. Describe the genetic basis of each type of variation, and explain how a t-test could be used to compare the mean egg counts between the two habitats.