Demise and Recolonization by the Tropical Fire Ant and Other Ants (Hymenoptera: Formicidae) in a Melon Field in Mexico

and can provide substantial reductions in populations of specific pests.Herein, we report on the population changes, as indicated by foraging activity, of S. geminata in a conventionally managed commercial muskmelon (Cucumis melo L. var.reticulatus) field with intensive pesticide and agrichemical use.Our objective was to obtain baseline data on changes in fire ant populations in response to crop phenology and agricultural practices from transplanting until harvest.The study was conducted at Santa Isabel, municipality of Cadereyta, Nuevo León state, Mexico (25°28 0 33 0 0 N, 100°00 0 31 0 0 W).The climate is subtropical dry, with a total precipitation of 600-800 mm/yr (National Institute of Statistics and Geography 1983, Secretaria de Programacin y Presupuesto, Mexico), and a mean temperature of 26°C (range, 25-42°C).The 1.5-ha muskmelon field was bordered on the eastern and western sides by weedy hedgerows (Fig. 1) occupied by pigweed, Amaranthus sp.; bitter weed, Parthenium hysterophorus L.; sunflower, Helianthus annuus L.; and bermudagrass, Cynodon dactylon (L.) Persoon.Senescent unplowed fields were ,30 m to the north (1.5-ha tomato [Solanum lycopersicum L.] field) and ,30 m to the east (3.0ha cabbage [Brassica oleracea L.] field; Fig. 1).Concurrent sampling of the two senescent fields during our study showed that S. geminata was a widespread, extremely abundant, and highly dominant aggressive predator of insects there during