It looks like some pretty heavy optimizations are needed if you want to be successful in one of those environments (daytime vs nighttime). Visual perception has to be fine-tuned for one of those environments. Perhaps thermal regulation is different too.

So I guess one possible explanation is that too many fine-tunings are required to work well in one environment, to allow the organism to be a good performer in both. So the logical choice is to withdraw from the other environment - just don't participate.