Butterflies have a Z/W mechanism of sex determination. In thissystem, females are the heterogametic sex, so females are ZW andmales are ZZ. Papilio glaucus, the Eastern Tiger Swallowtail, isfound throughout the eastern United States. Papilio canadensis, theCanadian Tiger Swallowtail, is found throughout Southern Canada andthe Northern United States. The two species are known to hybridizewhere their ranges overlap near the Great Lakes. For butterfliesliving in seasonal environments, it is important to correctly timethe diapause â a state of physiological dormancy that allows themto survive the winter. P. canadensis lives in colder climates andtherefore has only one generation per year and an obligatediapause; all pupae of this species diapause from late fall untilthe next spring, when they resume development. In P. glaucus, mostpupae diapause only in response to cold temperatures; as long asweather remains warm, they continue to develop. However, some P.glaucus pupae show obligate diapause similar to P. canadensis. Thegene that controls diapause in Papilio is located on the Zchromosome, and obligate diapause is specified by the recessiveallele ob. A population of P. glaucus near Lake Michigan is atHardy-Weinberg equilibrium. You have found that 9% of the malepupae show obligate diapause. You now bring P. canadensis and P.glaucus back to the lab to carry out some controlled crosses. TheP. canadensis population that you chose is fixed for the ob allele.The P. glaucus population that you chose is fixed for thealternative dominant allele at this locus that allows forenvironmental determination of diapause.
From the following matings, what is the frequency of diapausingpupae that you would expect? (Show how you calculated this).
All the info has been given
(2 points) Male canadensis x Female glaucus
Males:
Females:
(2 points) Male glaucus x Female canadensis
Males:
Females:
P.glaucus is highly palatable to predators. Females come in twoforms: a yellow form that looks identical to males and has somelevel of crypsis and a dark form, which mimics the unpalatablebutterfly Battus philenor. This trait is specific to females andthe locus that determines the phenotype is biallelic and located onthe W-chromosome.
(1 point) What form of mimicry is this?
(3 points) You are comparing two populations of P.glaucus foundin different regions. What factors do you think might influence therelative fitness of the two morphs?
(1 point) What type of selection would you expect to act on thegene responsible for color morph determination? (check one)
Negative Frequency Dependent Selection
Positive Frequency Dependent Selection
Balancing Selection
Directional Selection
Butterflies have a Z/W mechanism of sex determination. In thissystem, females are the heterogametic sex, so females are ZW andmales are ZZ. Papilio glaucus, the Eastern Tiger Swallowtail, isfound throughout the eastern United States. Papilio canadensis, theCanadian Tiger Swallowtail, is found throughout Southern Canada andthe Northern United States. The two species are known to hybridizewhere their ranges overlap near the Great Lakes. For butterfliesliving in seasonal environments, it is important to correctly timethe diapause â a state of physiological dormancy that allows themto survive the winter. P. canadensis lives in colder climates andtherefore has only one generation per year and an obligatediapause; all pupae of this species diapause from late fall untilthe next spring, when they resume development. In P. glaucus, mostpupae diapause only in response to cold temperatures; as long asweather remains warm, they continue to develop. However, some P.glaucus pupae show obligate diapause similar to P. canadensis. Thegene that controls diapause in Papilio is located on the Zchromosome, and obligate diapause is specified by the recessiveallele ob. A population of P. glaucus near Lake Michigan is atHardy-Weinberg equilibrium. You have found that 9% of the malepupae show obligate diapause. You now bring P. canadensis and P.glaucus back to the lab to carry out some controlled crosses. TheP. canadensis population that you chose is fixed for the ob allele.The P. glaucus population that you chose is fixed for thealternative dominant allele at this locus that allows forenvironmental determination of diapause.
From the following matings, what is the frequency of diapausingpupae that you would expect? (Show how you calculated this).
All the info has been given
(2 points) Male canadensis x Female glaucus
Males:
Females:
(2 points) Male glaucus x Female canadensis
Males:
Females:
P.glaucus is highly palatable to predators. Females come in twoforms: a yellow form that looks identical to males and has somelevel of crypsis and a dark form, which mimics the unpalatablebutterfly Battus philenor. This trait is specific to females andthe locus that determines the phenotype is biallelic and located onthe W-chromosome.
(1 point) What form of mimicry is this?
(3 points) You are comparing two populations of P.glaucus foundin different regions. What factors do you think might influence therelative fitness of the two morphs?
(1 point) What type of selection would you expect to act on thegene responsible for color morph determination? (check one)
Negative Frequency Dependent Selection
Positive Frequency Dependent Selection
Balancing Selection
Directional Selection
