Question

A butterfly species in a homogenous forest patch starts exhibiting assortative mating, such that spotted individuals always mate with each other and plain individuals always mate with each other. This trait is heritable, and spotted parents always produce spotted offspring and plain parents always produce plain offspring. Which one of the following forms of speciation could this prezygotic reproductive barrier most likely lead to?

• A. Sympatric speciation
• B. Cryptic speciation
• C. Allopatric speciation
• D. Peripatric speciation

Hint:

Sympatric speciation occurs when populations diverge into separate species within the same geographic area due to reproductive barriers, such as assortative mating.

Answer 1

The Correct Option is A

Step 1: Understand the concept of assortative mating.
Assortative mating occurs when individuals with similar traits (e.g., spotted or plain) preferentially mate with each other. This leads to reduced gene flow between the two groups, potentially creating a reproductive barrier.

Step 2: Recognize the form of speciation.
When reproductive isolation occurs without geographical separation, it may result in sympatric speciation. In this scenario, the population remains in the same location, but assortative mating leads to genetic divergence between subgroups.

Step 3: Eliminate other options.

• Cryptic speciation: Refers to species that are genetically distinct but appear morphologically identical—does not apply here.
• Allopatric speciation: Involves geographic isolation, which is not the case in this question.
• Peripatric speciation: Refers to speciation in a small, isolated peripheral population—not relevant here.

Conclusion: Since reproductive isolation occurs without geographic barriers and is driven by assortative mating, the correct answer is sympatric speciation.