The Importance of Using Multiple Approaches for Identifying Emerging Invasive Species: The Case of the Rasberry Crazy Ant in the United States

Abstract

In the past decade, Houston, Texas has been virtually overrun by an unidentified ant species, the sudden appearance and enormous population sizes and densities of which have received national media attention. The Rasberry Crazy Ant, as it has become known due to its uncertain species status, has since spread to neighboring states and is still a major concern to pest control officials. Previous attempts at identifying this species have resulted in widely different conclusions in regards to its native range, source, and biology. We identify this highly invasive pest species as Nylanderia fulva (Mayr) using morphometric data measured from 14 characters, molecular sequence data consisting of 4,669 aligned nucleotide sites from six independent loci and comparison with type specimens. This identification will allow for the study and control of this emerging pest species to proceed unencumbered by taxonomic uncertainty. We also show that N. fulva has a much wider distribution than previously thought and has most likely invaded all of the Gulf Coast states.

Boom and bust of the tawny Crazy Ant,Nylanderia fulva(Hymenoptera: Formicidae), on st. Croix, US Virgin Islands

“…In part, this is because of confusion about the identity of the ant species involved. In many earlier reports, N. fulva was misidentified as Nylanderia pubens Forel (formerly Paratrechina pubens), a closely related species whose workers cannot currently be differentiated reliably from N. fulva using only morphological characters (MacGown & Layton 2010;Gotzek et al 2012). Wetterer & Keularts (2008) reported an outbreak of N. fulva (misidentified as N. pubens) on the island of St. Croix, US Virgin Islands that began around 2002.…”

“…Unfortunately, almost all subsequent records of N. fulva are of unknown reliability because of problems with distinguishing N. fulva from other closely related species, notably N. pubens (Trager 1984;Gotzek et al 2012). Nylanderia fulva and N. pubens, however, may be distinguished using genetic analyses and male morphology (Gotzek et al 2012).…”

“…Unfortunately, almost all subsequent records of N. fulva are of unknown reliability because of problems with distinguishing N. fulva from other closely related species, notably N. pubens (Trager 1984;Gotzek et al 2012). Nylanderia fulva and N. pubens, however, may be distinguished using genetic analyses and male morphology (Gotzek et al 2012). Genetic analyses determined that the ants currently undergoing population explosions on St. Croix, first reported as N. pubens (Wetterer & Keularts 2008), are actually N. fulva (Gotzek et al 2012).…”

Myrmecomorba nylanderiae gen. et sp. nov., a microsporidian parasite of the tawny crazy ant Nylanderia fulva

“…Another invasive ant species in North America is Nylanderia fulva, the tawny crazy ant, which is native to central South America (Gotzek et al, 2012), but has recently become an important invasive species in the southeastern U.S. and several Caribbean islands where it can reach extremely high local densities (Wetterer et al, 2014) and displace native fauna (LeBrun et al, 2013). Efforts are underway in a number of U.S. laboratories to understand the biology (LeBrun et al, 2013(LeBrun et al, , 2014 and discover natural enemies (Valles et al, 2012a) of this important developing pest ant.…”

Relative Warp Analysis of the Pronotum Shape Variability among Twelve Selected Populations of the Coconut Leaf Beetle, Brontispa longissima Found in the Mindanao Island

“…The nature of founding events of invasions can be a vital determinant of their long-term success and impact, which is why they are generally intensely studied, often leading to important management decisions [5]. Studies on the extent of variability of invasive species are very important as these organisms contribute in the continuing decline in biodiversity as well as compete with man as most pests and weeds of agricultural systems do [6].…”