to interactions with other microbes in the soil influencing the relationship or the spatial structure of the soil preventing siderophore diffusion and therefore limiting the non-producer's ability to exploit the producer's siderophores. Selection pressure in bacteria (intraspecies) By definition, individuals cheat to gain benefits that their non-cheating counterparts do not receive. This raises the question of how a cooperative system can exist in face of these cheaters. One answer is that the cheaters actually have a reduced fitness compared to the non-cheaters. 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. 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 enjoy the benefits of the broken down resources. When P. aeruginosa populations are placed into growth conditions where cooperation (and responding to the quorum signal) is costly, the number of cheaters increases, and the public resources are depleted, which can lead to a tragedy of the commons. However, when P. aeruginosa populations are placed into growth conditions with a proportion of adenosine, the cheaters are suppressed because the bacteria that responds to the quorum signal now produces adenosine hydrolase that they privately use for themselves to digest adenosine food source. In wild populations where the presence of adenosine is common, this is an explanation for how individuals that cooperate could have higher fitness than those that cheat, thereby suppressing the cheaters and maintaining cooperation. Policing/punishment in insects Cheating is also commonly found in insects. The social and seemingly altruistic communities found in insects such as ants and bees provide ample opportunities for cheaters to take advantage of the system and accrue additional benefits at the expense of the community. Sometimes, a colony of insects is called a "superorganism" for its ability to take on properties greater than those of the sum of individuals. A colony of insects in which different individuals are specialized for specific tasks means a greater