Particle Size and Bait Preference of the Red Imported Fire Ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)

One of the most popular methods for achieving control of the Red Imported Fire\nAnt, Solenopsis invicta Buren, is through the use of broadcast baits. Several factors\ncontribute to bait efficacy, one of which may be particle size. The goals of these\nlaboratory studies were to determine particle size and bait preference using Advance\nSelect Granular Ant Bait and Advance Carpenter Ant Scatter Bait, determine the effect\nof starvation on bait removal and recruitment to Carpenter Ant Scatter Bait, and\ndetermine if any correlation existed between head capsule width and particle size\nselected.\nExperimental colonies removed significantly more 1400-2000 μm particles of\nSelect Granular Ant Bait, while ants foraging on Carpenter Ant Scatter Bait preferred\n1000-1400 μm particles. Mean number of ants present at bait mirrored results from bait\nremoval test. Ants displayed a preference for Carpenter Ant Scatter Bait based on mean\nnumber of ants present at bait for the 10-d foraging period.\nFor starvation assays, significant differences in bait removal and number of ants\npresent occurred in the 0-d group. Ants starved for 5 d removed significantly more bait of all particle sizes, and removed greater amounts of 1000-1400 μm Carpenter Ant\nScatter Bait than other sizes.\nHead width reliably predicted particle size selected, but the linear model\nexplained very little of the observed variation for ants foraging on Select Granular Ant\nBait (R2 = 0.043) or Carpenter Ant Scatter Bait (R2 = 0.047). This study supported the\nsignificant role of bait size and starvation period in S. invicta bait preference, and\ndemonstrated how size preference may vary depending on bait type.