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 Ant, Solenopsis invicta Buren, is through the use of broadcast baits. Several factors contribute to bait efficacy, one of which may be particle size. The goals of these laboratory studies were to determine particle size and bait preference using Advance Select Granular Ant Bait and Advance Carpenter Ant Scatter Bait, determine the effect of starvation on bait removal and recruitment to Carpenter Ant Scatter Bait, and determine if any correlation existed between head capsule width and particle size selected. Experimental colonies removed significantly more 1400-2000 ?m particles of Select Granular Ant Bait, while ants foraging on Carpenter Ant Scatter Bait preferred 1000-1400 ?m particles. Mean number of ants present at bait mirrored results from bait removal test. Ants displayed a preference for Carpenter Ant Scatter Bait based on mean number of ants present at bait for the 10-d foraging period. For starvation assays, significant differences in bait removal and number of ants present 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 ?m Carpenter Ant Scatter Bait than other sizes. Head width reliably predicted particle size selected, but the linear model explained very little of the observed variation for ants foraging on Select Granular Ant Bait (R2 = 0.043) or Carpenter Ant Scatter Bait (R2 = 0.047). This study supported the significant role of bait size and starvation period in S. invicta bait preference, and demonstrated how size preference may vary depending on bait type.