Avoidance of invasive prey reduces subsequent consumption of similar native prey

Abstract

Learned avoidance of invasive species could carry over to ecologically similar non-threatening native taxa, altering predator-prey interactions and food webs. The red imported fire ant, Solenopsis invicta, is an invasive prey of the eastern fence lizard, Sceloporus undulatus. Despite potentially lethal outcomes, juvenile fence lizards innately consume fire ants; however, they rapidly learn to avoid eating them with early-life exposure. Ants comprise a large portion of fence lizards' diets and a generalized avoidance of ants could thus reduce their prey pool. We tested whether learned avoidance following exposure to invasive fire ants would reduce the subsequent consumption of a palatable native ant. Lizards that consumed invasive fire ants for five days were less likely to subsequently consume native common pyramid ants, Dorymrymex bureni, than were lizards that initially consumed these non-threatening native ants. Our results suggest that learned avoidance of invasive prey can carry-over to avoidance of palatable native prey. The broad avoidance of native ants, due to the presence of invasive fire ants, could potentially increase native ant populations affecting their predators and competitors.