Urban Ant Ecology

Leong, C-H., Shiao, S-F. and B. Guénard. 2017. Ants in the city, a preliminary checklist of Formicidae (Hymenoptera) in Macau, one of the most heavily urbanized regions of the world. Asian Myrmecology 9:e009014 doi:10.20362/am.009014

ABSTRACT. Macau is a small territory in South East China and one of the most densely populated regions in the world. Previous studies on insect groups have shown that a relatively diverse, yet specific, fauna could still survive in this region. However, to this point, studies on the myrmecofauna of Macau are scarce and to date no species checklist exists. Here, we present the first checklist of Macanese ant species by combining results from recent ant surveys using hand-collections and Winkler extractors with published records. During the surveys, 82 species and morphospecies belonging to 37 genera and 8 subfamilies have been collected, with 37 species representing new records for Macau, including an interesting new record of an undescribed Leptanilla species, the second record of the Leptanillinae subfamily for South East China. To date, Macanese ants comprise 105 species/morphospecies and 8 subspecies, after the removal of dubious records present in the literature (though some misidentifications may remain). While still likely incomplete, these results represent the most comprehensive list of ants for Macau, and a baseline for future research on ant diversity in heavily urbanized environments and for understanding the potential consequences of urbanization on native and non-native diversity in Asia. -
 * Pecarevic, M., J. Danoff-Burg, and R. R. Dunn. 2010. Biodiversity on Broadway - Enigmatic diversity of the societies of ants (Formicidae) on the streets of New York City. PLoS ONE. 5(10): e13222:8 p. doi:10.1371/journal.pone.0013222

Abstract Each year, a larger proportion of the Earth’s surface is urbanized, and a larger proportion of the people on Earth lives in those urban areas. The everyday nature, however, that humans encounter in cities remains poorly understood. Here, we consider perhaps the most urban green habitat, street medians. We sampled ants from forty-four medians along three boulevards in New York City and examined how median properties affect the abundance and species richness of native and introduced ants found on them. Ant species richness varied among streets and increased with area but was independent of the other median attributes measured. Ant assemblages were highly nested, with three numerically dominant species present at all medians and additional species present at a subset of medians. The most common ant species were the introduced Pavement ant (Tetramorium caespitum) and the native Thief ant (Solenopsis molesta) and Cornfield ant (Lasius neoniger). The common introduced species on the medians responded differently to natural and disturbed elements of medians. Tetramorium caespitum was most abundant in small medians, with the greatest edge/area ratio, particularly if those medians had few trees, whereas Nylanderia flavipes was most abundant in the largest medians, particularly if they had more trees. Many of the species encountered in Manhattan were similar to those found in other large North American cities, such that a relatively small subset of ant species probably represent most of the encounters humans have with ants in North America.

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 * Roeder, K. A., D. V. Roeder, and M. Kaspari. 2018. The role of temperature in competition and persistence of an invaded ant assemblage. Ecological Entomology. 43:774-781. doi:10.1111/een.12663

Abstract. 1. To achieve numerical dominance, an ectotherm consumer requires a sizeable abiotic window in which it can forage. Here we explore how one abiotic factor, temperature, provides opportunity and regulates the impact of the invasive red imported fire ant, Solenopsis invicta, on an urban ant assemblage. 2.We first quantified S. invicta’s ability to outcompete native species by contrasting its foraging biomass to that of its potential competitors. In doing so, we found that S. invicta deployed more ant biomass at baits than the estimated whole colony biomass of three of the four co-occurring native species. It did so across c. 75% of the hours in a summer day, those hours below its thermal maximum of 49 ∘C. Higher thermal maxima allowed two native species to avoid encountering workers of S. invicta. 3. Exclosure experiments revealed that a third species, Dorymyrmex flavus, more similar in body size and thermal tolerance to S. invicta, was competitively suppressed by the invasive. Carbon and nitrogen stable isotope analysis suggests that D. flavus’ persistence is likely due to dietary differences. 4. Although thermal and dietary traits help predict how species coexist in this invaded assemblage, one key to S. invicta’s success is likely to be its ability to forage in all but 6 h of a summer’s day.