Effects of temperature and season on foraging activity of red imported fire ants (Hymenoptera: Formicidae) in Oklahoma

Temperature and seasonal effects on foraging activity of Solenopsis invicta Buren (red imported fire ant) in Oklahoma were investigated by periodically quantifying the number of ants captured in baited vials for 2 yr. All temperature parameters (soil surface, 2 cm, 15 cm, mound surface, mound 5 em deep, and mound 10 cm deep) except ambient at I m above soil surface were significant predictors of foraging activity; soil temperature at 15 cm was the best individual predictor, explaining 34% of variability in foraging activity. A combined quadratic model including mound surface temperature and season (weeks) explained 63% of the variability in foraging activity. Comparison with a similar study conducted in Florida revealed differences in the percentage of the year favorable for maximal foraging (approximate to25% in Oklahoma versus 42-59% in Florida). These data suggest that recommendations for timing of insecticidal bait applications against S. invicta that are appropriate in more southern portions of the fire ant range may not be appropriate for Oklahoma.