Effects of Pheidole megacephala (Hymenoptera: Formicidae) on survival and dispersal of Dysmicoccus neobrevipes (Homoptera: Pseudococcidae)

Abstract

We performed 2 laboratory experiments to determine if the bigheaded ant, Pheidole megacephala (F.), increases the size of populations of the gray pineapple mealybug, Dysmicoccus neobrevipes Beardsley, in the absence of natural enemies and adverse weather; if ants move mealybugs from one pineapple fruit to another under controlled conditions; and if mealybugs die of excess honeydew in the absence of ants that consume honeydew. In the 1st experiment, mealybugs were placed on preflowering pineapple plants with and without ants for 3 mo. In the 2nd experiment, mealybugs were placed on pineapple fruits with and without ants for 3 mo. In this experiment, ants had the opportunity to move mealybugs from one pineapple to another. In both experiments, mealybug populations tended by ants were not significantly larger than populations without ants. There was no evidence that ants transported mealybugs from one fruit to another. Nor was there evidence that the accumulation of honeydew resulted in increased D. neobrevipes mortality. The results of these experiments suggest that in the absence of natural enemies or inclement weather, P. megacephala do not cause an increase in mealybug population size, that ants do not move D. neobrevipes from pineapple to pineapple, and that the removal of honeydew by P. megacephala does not benefit D. neobrevipes.