In a study by Dandekar et al., the researchers examined the survival rates of cheating and non-cheating bacteria populations (Pseudomonas aeruginosa) under varying environmental conditions.[25] These microorganisms, like many species of bacteria, use a cell-cell communication system called quorum sensing that detect their population density and prompt the transcription of various resources when needed. In this case, the resources are publicly shared proteases that break down a food source like casein, and privately used adenosine hydrolase, which breaks down another food source, adenosine. The problem arises when some individuals (“cheaters”) do not respond to these quorum sensing signals and therefore do not contribute to the costly protease production yet enjoys the benefits of the broken down resources.