each worker assesses the quality of the cavity it finds. the worker then returns to the swarm and recruits other workers to her cavity using the honey bee waggle dance. however, instead of using a time delay, the number of dance repetitions the worker performs is dependent on the quality of the site. workers that found poor nests stop dancing sooner, and can, therefore, be recruited to the better sites. once the visitors to a new site sense that a quorum number (usually 10–20 bees) has been reached, they return to the swarm and begin using a new recruitment method called piping. this vibration signal causes the swarm to take off and fly to the new nest location. in an experimental test, this decision-making process enabled honey bee swarms to choose the best nest site in four out of five trials. synthetic biology quorum sensing has been engineered using synthetic biological circuits in different systems. examples include rewiring the ahl components to toxic genes to control population size in bacteria; and constructing an auxin-based system to control population density in mammalian cells. synthetic quorum sensing circuits have been proposed to enable applications like controlling biofilms or enabling drug delivery. quorum sensing based genetic circuits have been used to convert ai-2 signals to ai-1 and then subsequently use the ai-1 signal to alter bacterial growth rate, thereby changing the composition of a consortium. computing and robotics quorum sensing can be a useful tool for improving the function of self-organizing networks such as the secoas (self-organizing collegiate sensor) environmental monitoring system. in this system, individual nodes sense that there is a population of other nodes with similar data to report. the population then nominates just one node to report the data, resulting in power savings. ad hoc wireless networks can also benefit from quorum sensing, by allowing the system to detect and respond to network conditions. quorum sensing can also be used to coordinate the behavior of autonomous robot swarms. using a process similar to that used by temnothorax ants, robots can make rapid group decisions without the direction of a controller.