How can you determine if the glucose-aversion trait becomes more common in a cockroach population as a result of adaptive evolution?
Exterminators have observed that their hydramethylnon-corn syrup baits initially work for attracting cockroaches, but the effectiveness lessens over time. Does this mean that the aversion trait evolves in the cockroach populations exposed to the bait?
To answer this question, you need to identify a population of cockroaches with which you can perform an experiment. The experiment should be set up like this:
1. Observe and record the behavior of naïve cockroaches (never exposed to hydramethylnon) in a paired dish experiment using food with glucose and food without glucose. Record the number of cockroaches exhibiting the three phenotypes: glucose-attracted, intermediate, and glucose-averse. These represent the initial frequencies of wild type glu+ and mutant glu– alleles in the population.
2. Treat the cockroach population’s environment with hydramethylnon + glucose bait for 5 years.
3. After 5 years (about 15 generations), observe and record exposed cockroach behavior in a paired dish experiment using food with glucose and food without glucose. Record the number of cockroaches exhibiting the three phenotypes: glucose-attracted, intermediate, and glucose-averse.
4. Determine if the population of cockroaches exposed to hydramethylnon + glucose is at Hardy-Weinberg equilibrium, or if exposure to hydramethylnon + glucose caused a shift in allele frequencies in the population.
At the start of your experiment, suppose that you observed the genotypic distribution (based on phenotypic observations) shown in the table below in a naïve group of cockroaches in an infested apartment.
Fill in the numbers of alleles for the original naïve population. Once you know the numbers for each allele, calculate the frequency of each allele (p and q) to two decimal places.
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