Alternative mating strategies in the digger wasp Philanthus zebratus Cresson

Males of at least six species of the digger wasp genus Philanthus are territorial, defending areas on the ground and evidently marking these with a pheromone. This is also true of P. zebratus at two widely separate localities in Colorado. However, males in an aggregation in Jackson Hole, Wyoming, are nonterritorial and participate in flights serving to intercept females leaving and entering the nesting area. The evidence suggests that this novel strategy may have arisen de novo as a result of unknown ecological and historical factors.