Question

QUESTION 4

Recall the obligate mutualism of the Yucca moth with the Yucca plant in which the moth larvae feed and develop exclusively on the developing fruits of the Yucca plant and the moth adults are the sole pollinator for the Yucca plant. The number of eggs laid per female moth on a given Yucca flower is a genetically determined trait, and the frequency of individuals that lays different numbers of eggs per flower is given in the figure below. Based on what you know about mutualisms like this, what is the best explanation for why individuals that lay many (7 or more) eggs per flower are less common?

Group of answer choices

a.) Moths that voluntarily reduce their reproduction do not overexploit the resources provided by the plant and so are favored by natural selection.

b.) The number of eggs laid per flower is unrelated to moth fitness.

c.) The moth does no harm to the yucca plant, which by definition is true of all mutualistic relationships.

d.) The plant punishes cheater moths whose offspring use too much of any given flower by aborting those flowers.

e.) The number of eggs per flower is under disruptive selection.

Answer 1

Option C
Mutualisms is one of the types of Interspecific interactions where both the organisms are benefited.
Moth lays only few number of eggs per flower is because more number of eggs in a flower can lead to premature end of the flower or even if the flower is able to produce fruit more number of larvae will feed onto it for nutrition and hence will destroy the fruit and it will cause a negative effect on the Yucca plant and hence to minimise the harm, most of the times the moth lays eggs less than seven per flower.
Other options are wrong because natural selection favours the fittest organisms it has nothing to do whether that particular organisms overexploits or not provided that nutrition is enough for each larvae and even if they lay 1 egg per flower but are not capable of handling the climatic changes happening in the nature and will not be favoured by natural selection.
If number of eggs per flowers is too high the larvae will not get enough nutrition and hence will not survive.
option D is wrong. In case of Yucca plant the cheaters are those who steal the nectar without aiding the pollination.
Disruptive selection extreme values for a trait are favoured over intermediate values which does not apply for this case.