Some attine ants carry vegetation into their nests and add fungal material, thereby creating "gardens" in which fungal food for the ants grow. Because the ants play the behaviorally active role, it seems compelling to say that they cultivate and control the passive fungi. But even if that is true, the symbiotic association has existed for so long that cultivar traits may have evolved in the fungi that benefit the fungi but not necessarily the ants. Furthermore, many microorganisms have developed sophisticated mechanisms to manipulate the physiology and behavior of their symbiotic animals. It is not implausible, therefore, that the ants' fungi have evolved chemical and physiological schemes that alter ant behavior to serve the fungus' reproductive interests, possibly even compromising the reproductive interests for the ant hosts.