Meeting Abstract
Invasive species can pose novel threats to native species they encounter or act as novel food resources. Many studies that examine the consumption of invasive prey by native predators are conducted in the absence of native prey options. In order to better understand native predator preference, consumption of invasive prey must be measured in the presence of native prey options. The red imported fire ant, Solenopsis invicta, acts as a toxic predator and prey of the eastern fence lizard, Sceloporus undulatus. Ants compromise 50% to 80%, adult and juvenile respectively, of fence lizards diets; hence adapting to an invasive venomous ant prey could be vital. Here we test whether fence lizards prefer invasive fire ants or native non-venomous ants and whether this choice changes with experience. We presented lizards with three combinations of ants and recorded their consumption: 1) native non-venomous ants, Dorymyrmex bureni, only; 2) venomous invasive fire ants, S. invicta, only; and 3) both species presented simultaneously. On first exposure, the lizards killed more native ants than invasive fire ants. Of those ants killed, they consumed the majority of native ants, but crushed and discarded as many fire ants as they consumed. We discuss how the initial preference for native ants changes over time, and how the presence of a venomous species affects the consumption of native prey. Our results suggest that lizards can distinguish between an invasive and native ant species, which may facilitate avoidance or utilization of this novel prey. Lizards appear to kill toxic fire ants to remove them as a predatory threat, but primarily kill native ants for food. We highlight the importance of considering available prey in a landscape when determining consumption of invasive prey.
