Fire ant queens. Even if only one queen survives, within a month or so, the colony can expand to thousands of individuals. Some colonies may be polygynous (having multiple queens per nest). Fire ants are resilient and can survive floods. During Hurricane Harvey in Texas in 2017, clumps of fire ants, known as rafts, were seen clumped together on the surface of the water. Each clump had as many as 100,000 individual ants, which formed a temporary structure until finding a new permanent home. Fire ant queens, the reproductive females in their colony, also are generally the largest. Their primary function is
Ant colony optimization algorithms formula_26 and formula_27 represent the attractiveness and trail level for the other possible state transitions. When all the ants have completed a solution, the trails are updated by formula_28 where formula_10 is the amount of pheromone deposited for a state transition formula_21, formula_31 is the "pheromone evaporation coefficient" and formula_32 is the amount of pheromone deposited by formula_3th ant, typically given for a TSP problem (with moves corresponding to arcs of the graph) by formula_34 where formula_35 is the cost of the formula_3th ant's tour (typically length) and formula_37 is a constant. Ant colony optimization algorithms have been applied to