Cockroaches: Cockroaches are nocturnal meaning they are most active at night. During the daytime they hide in cracks, crevices, and dark harborage areas. If you are seeing cockroaches during the daytime you may have a serious infestation. Cockroaches are serious scavengers and eat the same foods humans eat. In the process of scavenging for food cockroaches leave behind excrement that contaminates food and surfaces. Cockroaches are vectors of e-coli, staphylococcus and streptococcus bacteria and can also carry dysentery. Good sanitation practices are a deterrent to cockroach infestation.