On an opposite note, I remember when I use to provide pest control for a penitentiary. The basement of the facility was where al the access to the plumbing and electrical areas were. It was a constant 90 degrees and the humidity was equally as high. There were massive colonies of American roaches living there. The building was supported by concrete pillars and they would hang on these like herds of sheep. Moving as a group (not scattering)if you shown a flash light on them. The interesting thing is this area was lit 24/7. The did not hang out in the dim areas. We sprayed once a week and there were never in dead to be found. I almost think they lived solely off the dead we created. So it appears once roaches get used to a particular light cycle it is of little matter to them.