Research with another bacterium that kills insects has shown that in the appropriate situation each individual bacterium can alter its behavior. Thus, when this bacterium resides in the intestine of its usual host, a small parasitic worm, it cooperates with its host and both the worm and the bacterium benefit from the relationship. However, when this juvenile worm parasitizes a susceptible insect it regurgitates these bacteria from its gut. The bacteria then revert to a pathogenic state and proceed to make the toxins that allow the worm to mature by consuming the dying insect. This is not unlike soldiers who in their own country are benign cooperators among their fellow citizens but when sent to subdue another country behave as lethal aggressors.
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