Invasive ants influence native lizard populations

Authors: DARRACQ, ANDREA - North Georgia College And State University; SMITH, LORA - Jones Ecological Resesearch Center; Oi, David; CONNER, L - Jones Ecological Resesearch Center; MCCLEERY, ROBERT - University Of Florida

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2016
Publication Date: 1/6/2017
Citation: Darracq, A.K., Smith, L.L., Oi, D.H., Conner, L.M., Mccleery, R.A. 2017. Invasive ants influence native lizard populations. Ecosphere. 81(1):1-17. doi:e01657. 10.1002/ecs2.1657.

Interpretive Summary: Red imported fire ants (RIFA), Solenopsis invicta, is an invasive predator found in North and South America, Australia, and Asia. RIFA are implicated in the decline of native invertebrates and vertebrates throughout their invaded range. Researchers from the University of Florida, the Jones Ecological Research Center, and ARS Center for Medical, Agricultural, and Veterinary Entomology utilized the eastern fence lizard, Sceloporus undulatus, as a model species to understand the influence of RIFA on native reptiles in the southeastern United States. The objective was to quantify the effects of RIFA on fence lizard recruitment (i.e. increases in lizard populations) and survival. Populations of fence lizards were stocked into eight enclosures with either natural RIFA populations or reduced numbers of RIFA, obtained by fire ant bait applications, from May 2012 to October 2013. Fitting models that predict population increases from birth and immigration, enclosures with less RIFA had 1.6 times greater fence lizard recruitment but no impact on survival relative to enclosures with natural RIFA numbers. RIFA likely have similar effects on reptiles with analogous life history strategies to that of fence lizards. Consequently, RIFA may have undesirable consequences for the biodiversity of reptiles in the southeastern United States and on other continents with established RIFA populations.

Technical Abstract: The red imported fire ant (Solenopsis invicta; hereafter RIFA) is an invasive predator found on four continents, including South America, North America, Australia, and Asia. RIFAs are implicated in the decline of native invertebrates and vertebrates throughout their invaded range. We used the eastern fence lizard (Sceloporus undulatus) as a model species to understand the influence of RIFAs on native reptiles in the southeastern United States. Our objective was to quantify the effects of RIFAs on fence lizard recruitment and survival. We experimentally stocked populations of fence lizards into eight enclosures with either ambient (n = 4) or reduced (n = 4) numbers of RIFAs from May 2012 to October 2013. Fitting Link-Barker models we found that the RIFA treatment affected fence lizard recruitment (f) but not survival (F). Recruitment was 1.6 times greater in the enclosures with reduced numbers of RIFAs (2012: f = 1.01 ± 0.13, 2013: f = 0.29 ± 0.06) than those with ambient numbers (2012: f = 0.61 ± 0.17, 2013: f = 0.17 ± 0.05). RIFAs likely affect reptiles with analogous life history strategies to that of fence lizards similarly. Consequently, RIFAs may have undesirable consequences for the biodiversity of reptiles in the southeastern United States and on other continents with established RIFA populations.