Sympatric speciation example in insects involves:
Sympatric speciation arises within same geographic area without physical barrier, often via polyploidy in plants where chromosome doubling creates instant reproductive isolation because tetraploids produce sterile triploid hybrids with diploid parents. Host shifts in insects and disruptive selection also drive sympatric divergence. Molecular studies show cichlid fishes diverging in same lake. This mode demonstrates speciation without geographic separation, defined as Wolbachia infection. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.
Ref: Coyne & Orr, Speciation, Chapter 1: Species Concepts and Isolation.