@article {33512, title = {Ecological impacts on native ant and ground-dwelling animal communities through Argentine ant (Linepithema humile) (Hymenoptera: Formicidae) management in Japan}, journal = {Applied Entomology and Zoology}, year = {2015}, month = {Sep-04-2016}, abstract = {

In the last 30\ years some limited successes in alien ant control have been documented globally, and control programs remain challenging. Moreover, the potential non-target impacts of toxicants have not been well studied. We assessed the efficacy and non-target effects of multiple products containing the active compound fipronil in the attempted control of two populations of the invasive Argentine ant\ Linepithema humile\ (Mayr) in Tokyo, Japan. Three treatments were conducted: control, low-dose treatment (0.1\ g/ha per treatment), and high-dose treatment (0.2\ g/ha). Treatments were applied once per month for 11\ months. The abundance of\ L. humile\ declined rapidly by up to 99.8\ \% in treated areas, but remained at extremely high densities in the control area. The treatments had few negative non-target effects, with the abundances of native ant species and other ground-dwelling invertebrates except for cockroaches being greater in the treated areas after\ L. humile\ suppression. Thus, fipronil is an effective compound for controlling\ L. humile\ and can be used with minimal toxic effects on non-target organisms. The treatments cost approximately US$ 575/ha for the low-dose treatment and US$ 1250/ha for the high-dose treatment. Our research supports the creation of more ambitious invasive ant management projects.

}, keywords = {biological invasion, Eradication, Fipronil, Linepithema humile, Non-target effects}, issn = {0003-6862}, doi = {10.1007/s13355-015-0338-7}, url = {http://link.springer.com/10.1007/s13355-015-0338-7http://link.springer.com/content/pdf/10.1007/s13355-015-0338-7}, author = {Inoue, Maki N. and Saito-Morooka, Fuki and Suzuki, Kazutaka and Nomura, Takuji and Hayasaka, Daisuke and Kishimoto, Toshio and Sugimaru, Katsuo and Sugiyama, Takashi and Goka, Koichi} } @article {33511, title = {Intermediate disturbance promotes invasive ant abundance}, journal = {Biological Conservation}, volume = {186}, year = {2015}, month = {Jan-06-2015}, pages = {359 - 367}, abstract = {

Urban habitats are undergoing a faunal and floral homogenization process worldwide. We investigated how such homogenization influences ant communities. We monitored ant species richness and abundance in natural, semi-natural, urban, and agricultural habitats for one year, along an urban\–rural gradient in the San Francisco Bay Area, and examined which human-related and other environmental variables most affect ant distribution. We investigated whether alien ant species have an advantage in human-modified habitats. We found that distance from buildings was the most important factor affecting ant distribution. In total, we recorded 17 ant species, of which four were non-native. Native ant species richness was highest in natural habitats, and alien species richness was highest in urban habitats. Remarkably, in a sample of 19,450 ant workers at food baits, the highest ant abundance across all seasons was in the semi-natural habitat where usually only the invasive Argentine ant (Linepithema humile), representing 81\% of all ants seen at baits, and the native winter ant (Prenolepis imparis) were present. Agricultural habitats had a surprisingly high number of native and alien species. It appears that the invasive Argentine ant creates a favorable ecological community in semi-natural environments, where they compete successfully with the native species, and do not face the increased competition with other alien species that they encounter in urban habitats. Even well protected natural habitat may be favorable for invasive species, due to its proximity to human disturbance.

}, keywords = {biodiversity, biological invasions, Linepithema humile, Urban ecology, Urban{\textendash}rural gradient}, issn = {00063207}, doi = {10.1016/j.biocon.2015.03.024}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0006320715001354http://api.elsevier.com/content/article/PII:S0006320715001354?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0006320715001354?httpAccept=text/plain}, author = {Vonshak, Merav and Gordon, Deborah M.} } @article {33499, title = {Density-Dependent effects of an invasive ant on a ground-dwelling arthropod community}, journal = {Environmental Entomology}, year = {2015}, month = {2015/01/21}, abstract = {

It is frequently assumed that an invasive species that is ecologically or economically damaging in one region, will typically be so in other environments. The Argentine ant Linepithema humile (Mayr) is listed among the world\’s worst invaders. It commonly displaces resident ant species where it occurs at high population densities, and may also reduce densities of other ground-dwelling arthropods. We investigated the effect of varying Argentine ant abundance on resident ant and nonant arthropod species richness and abundance in seven cities across its range in New Zealand. Pitfall traps were used to compare an invaded and uninvaded site in each city. Invaded sites were selected based on natural varying abundance of Argentine ant populations. Argentine ant density had a significant negative effect on epigaeic ant abundance and species richness, but hypogaeic ant abundance and species richness was unaffected. We observed a significant decrease in Diplopoda abundance with increasing Argentine ant abundance, while Coleoptera abundance increased. The effect on Amphipoda and Isopoda depended strongly on climate. The severity of the impact on negatively affected taxa was reduced in areas where Argentine ant densities were low. Surprisingly, Argentine ants had no effect on the abundance of the other arthropod taxa examined. Morphospecies richness for all nonant arthropod taxa was unaffected by Argentine ant abundance. Species that are established as invasive in one location therefore cannot be assumed to be invasive in other locations based on presence alone. Appropriate management decisions should reflect this knowledge.

}, keywords = {abundance, arthropod, density-dependence, impact, Linepithema humile}, url = {http://ee.oxfordjournals.org/content/early/2015/01/21/ee.nvu008.abstract}, author = {Cooling, M. and Sim, D. A. and Lester, P. J.} } @article {33465, title = {Individual variation in exploratory behaviour improves speed and accuracy of collective nest selection by Argentine ants}, journal = {Animal Behaviour}, volume = {93}, year = {2014}, month = {Jan-07-2014}, pages = {261 - 266}, abstract = {

Collective behaviours are influenced by the behavioural composition of the group. For example, a collective behaviour may emerge from the average behaviour of the group\&$\#$39;s constituents, or be driven by a few key individuals that catalyse the behaviour of others in the group. When ant colonies collectively relocate to a new nest site, there is an inherent trade-off between the speed and accuracy of their decision of where to move due to the time it takes to gather information. Thus, variation among workers in exploratory behaviour, which allows gathering information about potential new nest sites, may impact the ability of a colony to move quickly into a suitable new nest. The invasive Argentine ant,\ Linepithema humile, expands its range locally through the dispersal and establishment of propagules: groups of ants and queens. We examine whether the success of these groups in rapidly finding a suitable nest site is affected by their behavioural composition. We compared nest choice speed and accuracy among groups of all-exploratory, all-nonexploratory and half-exploratory\–half-nonexploratory individuals. We show that exploratory individuals improve both the speed and accuracy of collective nest choice, and that exploratory individuals have additive, not synergistic, effects on nest site selection. By integrating an examination of behaviour into the study of invasive species we shed light on the mechanisms that impact the progression of invasion.

}, keywords = {Argentine ant, behavioural syndrome, collective behaviour, dispersal, group composition, individual variation, Linepithema humile, personality, range expansion, relocation}, issn = {00033472}, doi = {10.1016/j.anbehav.2014.05.006}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347214002255http://api.elsevier.com/content/article/PII:S0003347214002255?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0003347214002255?httpAccept=text/plain}, author = {Hui, Ashley and Pinter-Wollman, Noa} } @article {33463, title = {Resource competition assays between the African big-headed ant, Pheidole megacephala (Fabricius) and the invasive Argentine ant, Linepithema humile (Mayr): mechanisms of inter-specific displacement}, journal = {Ecological Entomology}, year = {2014}, month = {Jan-05-2014}, pages = {n/a - n/a}, abstract = {

1. The spread of Argentine ants,\ Linepithema humile\ (Mayr), in introduced areas is mainly through the displacement of native ant species owing to high inter-specific competition. In South Africa,\ L. humile\ has not established in the climatically suitable eastern and northern escarpments dominated by the African big headed ant,\ Pheidole megacephala\ (Fabricius), probably owing to local biotic resistance.

2. Inter-specific aggression, at the individual and colony level, and competition for a shared resource were evaluated in the laboratory.

3. Aggression between the two ant species was very high in all of the assays. Both species suffered similar mortality rates during one-on-one aggression assays, however, during symmetrical group confrontations,\ L. humile\ workers showed significantly higher mortality rates than\ P. megacephala\ workers. During asymmetrical group confrontations both species killed more of the other ant species when they had numeric advantage. Both ant species located the shared resource at the same time; however, once\ P. megacephala\ discovered the bait, they displaced\ L. humile\ from the bait through high inter-specific aggression, thereafter dominating the bait for the remainder of the trial.

4. The results demonstrate the potential of\ P. megacephala\ to prevent the establishment and survival of incipient\ L. humile\ colonies through enhanced resource competition and high inter-specific aggression. This is the first study to indicate potential biotic resistance to the spread of\ L. humile\ in South Africa.

}, keywords = {Argentine ant, big-headed ant, Biotic resistance, foraging efficiency, inter-specific competition, Linepithema humile, Pheidole megacephala}, doi = {10.1111/een.12126}, url = {http://doi.wiley.com/10.1111/een.12126}, author = {Mothapo, Natasha P and Wossler, Theresa C} }