@article{brightwell_silverman_2011, title={The Argentine Ant Persists Through Unfavorable Winters Via a Mutualism Facilitated By a Native Tree}, volume={40}, ISSN={["1938-2936"]}, DOI={10.1603/en11038}, abstractNote={ABSTRACT 
 Mutualisms and facilitations can fundamentally change the relationship between an organism's realized and fundamental niche. Invasive species may prove particularly suitable models for investigating this relationship as many are dependent on finding new partners for successful establishment. We conducted field-based experiments testing whether a native tree facilitates the successful survival of the invasive Argentine ant, Linepithema humile (Mayr), through unfavorable winter conditions in the southeastern United States. We found Argentine ant nests aggregated around the native loblolly pine, Pinus taeda L., during the winter months. The bark of this tree absorbed enough radiant solar energy to reach temperatures suitable for Argentine ant foraging even when ambient temperatures should have curtailed all foraging. Conversely, foraging ceased when the trunk was shaded. The sun-warmed bark of this tree gave the Argentine ant access to a stable honeydew resource. Argentine ants were not found on or near deciduous trees even though bark temperatures were warm enough to permit Argentine ant foraging on cold winter days. Augmenting deciduous trees with sucrose water through the winter months lead to Argentine ant nests remaining at their base and Argentine ants foraging on the tree. The Argentine ant requires both foraging opportunity and a reliable winter food source to survive through unfavorable winter conditions in the southeastern United States. The loblolly pine provided both of these requirements extending the realized niche of Argentine ants beyond its fundamental niche.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Brightwell, Robert J. and Silverman, Jules}, year={2011}, month={Oct}, pages={1019–1026} }
 @article{brightwell_bambara_silverman_2010, title={Combined Effect of Hemipteran Control and Liquid Bait on Argentine Ant Populations}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec10150}, abstractNote={ABSTRACT 
 The invasive Argentine ant, Linepithema humile (Mayr), has become a worldwide problem capable of inflicting significant ecological and economic injury on urban, agricultural, and natural environments. The mobility of this pest ant has long been noted, rapidly moving nests to new food resources and then away as resources are depleted. This ant, like many pest ant species, has a special affinity for honeydew excreted by phloem-feeding Hemiptera. We investigated the effect of various hemipteran control strategies on terrapin scale densities and measured their indirect effect on local Argentine ant densities and foraging effort. We then determined whether this indirect treatment strategy improved the performance of an ant bait. We predicted that Argentine ants would move nests away from trees treated for Hemiptera and then move nests back when a liquid bait was offered, followed by a decline in ant numbers due to intake of the toxicant. A horticultural oil spray and soil application of the systemic insecticide, imidacloprid, had no effect on terrapin scale numbers. However, trunk-injected dicrotophos caused a reduction in scale and a decline in local Argentine ant nest density and canopy foraging effort. We also recorded a reduction in local Argentine ant ground foraging when large amounts of liquid bait were applied, and we found no evidence that combining dicrotophos with liquid ant bait performed better than each treatment alone. We suggest that a strategy of combined hemipteran control plus application of liquid ant bait can reduce local Argentine ant densities, when both components of this system are highly efficacious.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Brightwell, R. J. and Bambara, S. B. and Silverman, J.}, year={2010}, month={Oct}, pages={1790–1796} }
 @article{brightwell_labadie_silverman_2010, title={Northward Expansion of the Invasive Linepithema humile (Hymenoptera: Formicidae) in the Eastern United States is Constrained by Winter Soil Temperatures}, volume={39}, ISSN={["0046-225X"]}, DOI={10.1603/en09345}, abstractNote={ARSTRACT 
 The invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) has been evident in the North Carolina Piedmont, United States for 90 yr but has failed to spread further north. We investigated the mechanisms preventing this expansion. The Argentine ant ceases foraging at temperatures below 5°C and we hypothesized that winter soil temperatures at higher latitudes restricted foraging long enough to cause colony starvation. We tested if the Argentine ant could successfully feed at temperatures below 5°C and found that colonies would starve. We subjected Argentine ant nests to a range of sub- and above-freezing temperatures and measured worker mortality at various time intervals. We found that Argentine ant colonies will collapse after 8.5 d at 5°C Argentine ants can escape ambient cold temperatures by moving nests into the soil column. We tested how deeply into the soil Argentine ant queens and workers need to move to survive winter in North Carolina. Soil temperatures in the North Carolina Piedmont do not fall below 5°C for longer than nine consecutive days; therefore, Argentine ant colonies need only to retreat a few centimeters into the soil column to escape unsuitable temperatures. Winter soil temperature data from four climate stations situated from latitudes 35°, the current Eastern United States latitudinal limit for Argentine ant population expansion, to 39° were searched for periods where soil temperatures would have led to colony extirpation. North of their current distributions, extended periods of soil temperatures below 5°C regularly occur, preventing Argentine ant colonies from persisting.}, number={5}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Brightwell, R. J. and Labadie, P. E. and Silverman, J.}, year={2010}, month={Oct}, pages={1659–1665} }
 @article{brightwell_silverman_2009, title={Effects of Honeydew-Producing Hemipteran Denial on Local Argentine Ant Distribution and Boric Acid Bait Performance}, volume={102}, ISSN={["1938-291X"]}, DOI={10.1603/029.102.0340}, abstractNote={ABSTRACT 
 The Argentine ant is well known for its affinity for honeydew and is often associated with hemipteran outbreaks in agricultural and urban environments. It has been suggested that Argentine ants may be controlled by restricting access to honeydew, thereby forcing the ants to move or by encouraging increased liquid toxicant intake. We tested this possible control strategy by restricting Argentine ant access to the honeydew-producing terrapin scale within the canopy of red maple trees and monitoring ant numbers with pitfall traps and nest counts in the mulch around the tree base. Argentine ant nest numbers fell dramatically in the mulch around ant-excluded trees; however, there was no reduction in Argentine ant numbers caught in pitfalls around trees with or without canopy access. We added 0.5% boric acid bait stations at the base of the red maples and monitored bait consumption. Pitfall and nest counts were not affected by the addition of boric acid, although bait consumption was lower around ant-excluded trees, suggesting that restricting access to honeydew-producing Hemiptera did not enhance bait performance. We attribute this result to the increased distance Argentine ant workers had to trail from nest to bait station when not tending nearby terrapin scale. We suggest an alternative management strategy concentrating direct insecticidal control of Argentine ants around a few host plants infested with honeydew-producing Hemiptera by controlling Hemiptera in nearby host plants.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Brightwell, R. J. and Silverman, J.}, year={2009}, month={Jun}, pages={1170–1174} }
 @article{brightwell_silverman_2010, title={Invasive Argentine ants reduce fitness of red maple via a mutualism with an endemic coccid}, volume={12}, ISSN={["1573-1464"]}, DOI={10.1007/s10530-009-9607-0}, number={7}, journal={BIOLOGICAL INVASIONS}, author={Brightwell, Robert John and Silverman, Jules}, year={2010}, month={Jul}, pages={2051–2057} }
 @article{brightwell_silverman_2007, title={Argentine ant foraging activity and interspecific competition in complete vs. queenless and broodless colonies}, volume={54}, ISSN={["1420-9098"]}, DOI={10.1007/s00040-007-0950-9}, number={4}, journal={INSECTES SOCIAUX}, author={Brightwell, R. J. and Silverman, J.}, year={2007}, pages={329–333} }
 @article{silverman_brightwell_2008, title={The Argentine ant: Challenges in managing an invasive unicolonial pest}, volume={53}, ISSN={["1545-4487"]}, DOI={10.1146/annurev.ento.53.103106.093450}, abstractNote={ The Argentine ant, Linepithema humile, has invaded urban, agricultural, and natural habitats worldwide, causing economic damage and disrupting ecosystem processes. Introduced populations of L. humile and those of many other invasive ants tend to be unicolonial, forming expansive, multiqueened supercolonies that dominate native ant communities and challenge control practices in managed habitats. Argentine ant management typically entails the application of residual insecticide liquids, granules, or baits to only a portion of the colony, resulting in fairly rapid reinfestation. We suggest that prevailing control methodologies are incomplete and not compatible with the behavior, nesting habits, and population structure of this ant, and therefore, more aggressive management strategies are required. Successful eradication efforts against other invasive unicolonial ant species can provide useful insights for local-scale L. humile eradication. }, journal={ANNUAL REVIEW OF ENTOMOLOGY}, author={Silverman, Jules and Brightwell, Robert John}, year={2008}, pages={231–252} }