Sex in a virtual reality: experimental evidence for sexual isolation due
to variation in perception of the environment
Abstract
Differential perception and subsequent differential use of habitats can
generate local adaptation, especially when natural selection cannot.
However, this local adaptation is not maintained into future generations
unless mating happens within the chosen habitats. We currently have no
experimental data on whether differential perception of environments
results in sexual isolation. We induced differential perception of
environments by stimulating different olfactory neurons via light pulses
(optogenetics) in two groups of fruit flies. These flies were released
in a cage of which only one section received light pulses. One group of
flies perceives this optogenetic stimulation as the smell of a harmful
concentration of CO2 and was found to avoid the illuminated section. The
other group perceives it as the smell of food-related compounds and was
found to be attracted to the illuminated section. Due to this
self-imposed spatial segregation, we subsequently observed a
considerable degree of sexual isolation between the two groups of flies.
In contrast, in two control treatments preventing differential
perception of the environment, sexual isolation was virtually absent.
Our results show that differential perception of the environment can
easily and rapidly generate spatial segregation and sexual isolation
among individuals that are ecologically different. This can maintain
local adaptation, especially under conditions when natural selection
cannot, which are increasingly common due to human-induced rapid
environmental change.