Reproductive isolation arises during laboratory adaptation to a novel hot environment.

Area of Science:

• Evolutionary Biology
• Speciation Research
• Genetics

Background:

• Reproductive isolation can arise from adaptive processes like ecological speciation or stochastic processes such as system drift.
• Ecological speciation predicts gene flow barriers between populations in different environments, not within the same environment.
• Mutation-order speciation or system drift can cause reproductive isolation in populations adapting to similar environments.

Purpose of the Study:

• To investigate the mechanisms of reproductive isolation in experimentally evolved populations.
• To determine if premating and postmating isolation arise during adaptation to a novel environment.
• To explore the role of ecological speciation, mutation-order speciation, and system drift in rapid speciation.

Main Methods:

• Experimental evolution of populations adapting to a hot environment for over 100 generations.
• Analysis of lipid metabolism and cuticular hydrocarbon composition for premating isolation.
• Examination of gene expression differences in male reproductive genes for postmating isolation.

Main Results:

• Evidence for both premating and postmating reproductive isolation was found in experimentally evolved populations.
• Altered lipid metabolism and cuticular hydrocarbons suggest premating barriers between ancestral and evolved populations.
• Pronounced gene expression differences in male reproductive genes indicate potential postmating isolation among replicate populations.

Conclusions:

• Replicated evolution experiments offer insights into speciation mechanisms.
• Rapid premating reproductive isolation during temperature adaptation supports incipient ecological speciation.
• Potential postmating isolation among replicates suggests mutation-order speciation or system drift as underlying causes.