@article {33416, title = {Quantification of supercolonial traits in the yellow crazy ant, Anoplolepis gracilipes}, journal = {Journal of Insect Science}, volume = {14}, year = {2014}, pages = {1-21}, abstract = {

Supercoloniality is a social structure displayed by many invasive ant species, but there has been surprisingly little research quantifying the extent to which individual species display traits underlying such social organisation. This study quantifies three traits for the yellow crazy ant,Anoplolepis gracilipes\ Smith (Hymenoptera: Formicidae): little or no aggression between workers from different nests; the exchange of workers among nests; and resource exchange among nests, as well as supercolony structure arising from patterns of distribution and density of detections. Supercolonies displayed a structural continuum from being small (\< 10 ha) and \“aggregated\” with great continuity among detections through to being large (\> 10,000 ha) and \“diffuse\” with little continuity among detections. Smaller supercolonies had greater ant densities than larger supercolonies. In laboratory trials, no aggression was observed between workers from different nests sourced from different supercolonies, and paired nests merged within 24 hours. Workers lacked nest fidelity by rapidly populating artificial nests containing alien queens. The daily worker turnover rate per nest was estimated to be below 20\%. Resources were readily moved among nests, with a resource being detected up to 13 m away from a source within 24 hours, and as far as 32 m after four days. The rate and distance of resource movement increased with increasing worker and nest density. This research has demonstrated that\ A. gracilipes\ displays supercoloniality equivalent to that of the well-studied Argentine ant\ Linepithema humile. Quantification of these traits is required for other supercolonial species to improve our understanding of this social strategy, especially for invasive ants to aid in understanding factors that promote invasion success and to improve management.

}, keywords = {colony, invasion, nest fidelity, polygyny, resource flow, supercolony}, issn = {1536-2442}, url = {http://www.insectscience.org/14.25}, author = {Hoffmann, B. D.} } @article {3729, title = {Taxonomic confusion of two tramp ant species: Iridomyrmex anceps and Ochetellus glaber are really species complexes}, journal = {Curr. Zool.}, volume = {57}, number = {5}, year = {2011}, note = {ISI Document Delivery No.: 800EXTimes Cited: 0Cited Reference Count: 33Hoffmann, Benjamin D. Andersen, Alan N. Zhang, Xiang}, pages = {662-667}, type = {Article}, abstract = {Many invasive invertebrates belong to unresolved species complexes, and have a history of misidentification and inappropriate management. Here we detail confusion surrounding the taxonomy and identification of two dolichoderine ant species, Iridomyrmex anceps Roger and Ochetellus glaber Mayr, which are commonly cited in the literature as having been spread widely by human commerce. We provide morphometric data and images strongly suggesting that these two "species" are instead complexes of species that are likely native to many regions where they are purportedly introduced. We take particular interest in the status of species referred to as I. anceps and O. glaber in China, as this is the most northerly distribution of both genera. We conclude by suggesting that many identifications of both species are likely to be unreliable, and we recommend against any management action aimed at controlling these species under the assumption that they are exotic [Current Zoology 57 (5): 662-667, 2011].}, isbn = {1674-5507}, author = {Hoffmann, B. D. and Andersen, A. N. and Zhang, X.} } @article {3730, title = {Yellow crazy ant (Anoplolepis gracilipes) invasions within undisturbed mainland Australian habitats: no support for biotic resistance hypothesis}, journal = {Biological Invasions}, volume = {12}, year = {2010}, note = {Part of FORMIS 10; from NAL{\textquoteright}S AGRICOLA;from-DPW, }, month = {Sept. 2010; Publ}, pages = {3093-3108}, abstract = {Ants are highly successful invaders, especially on islands, yet undisturbed mainland environments often do not contain invasive ants, and this observation is largely attributed to biotic resistance. An exception is the incursion of Yellow crazy ant Anoplolepis gracilipes within northeast Arnhem Land. The existence of A. gracilipes within this landscape{\textquoteright}s intact environments containing highly competitive ant communities indicates that biotic resistance is not a terminally inhibitory factor mediating this ant{\textquoteright}s distribution at the regional scale. We test whether biotic resistance may still operate at a more local scale by assessing whether ecological impacts are proportional to habitat suitability for A. gracilipes, as well as to the competitiveness of the invaded ant community. The abundance and species richness of native ants were consistently greater in uninfested than infested plots but the magnitude of the impacts did not differ between habitats. The abundance and ordinal richness of other macro-invertebrates were consistently lower in infested plots in all habitats. A significant negative relationship was found for native ant abundance and A. gracilipes abundance. No relationships were found between A. gracilipes abundance and any measure of other macro-invertebrates. The relative contribution of small ants (<2.5 mm) to total abundance and relative species richness was always greater in infested sites coinciding with a reduction of the contribution of the larger size classes. Differences in the relative abundance of ant functional groups between infested and uninfested sites reflected impacts according to ant size classes and ecology. The widespread scale of these incursions and non-differential level of impacts among the habitats, irrespective of native ant community competitiveness and abiotic suitability to A. gracilipes, does not support the biotic resistance hypothesis.}, author = {Hoffmann, B. D. and Saul, W.C.} }