Technomyrmex albipes, a New Exotic Ant in Florida (Hymenoptera: Formicidae)

Abstract

On 11 May 1990, at Florida International University (Miami), there was meeting on the changing landscape of south Florida, emphasizing the wholesale invasions of exotic biota. It is appropriate that this meeting was discreetly attended by new exotic ant, Technomyrmrex albipes (Fr. Smith) (Dolichoderinae), which visited the water fountain in the lecture hall and scavenged doughnut crumbs outside during breaks in the program. It seems likely that this species, camouflaged among similar-appearing Paratrechina spp., is now established in south Florida. Judging by its habits and spread elsewhere in tropical and subtropical areas, T. albipes could become an abundant species in south Florida. T. albipes (Fig. 1) is easily distinguished from other local dolichoderines by the following structural characters: petiolar scale absent; propodeum angulate; propodeum and mesonotum conspicuously granulate. It bears superficial resemblance to species of the formicine genus Paratrechina (but lacks robust setae), to the dolichoderines Forelius pruinosus (Roger) (but is more granulate, with conspicuous yellow tarsi) and Tapinoma sessile (Say) (but is more granulate with conspicuous erect setae and yellow tarsi). In life, T. albipes strongly resembles species of Paratrechina, especially P. bourbonica (Forel), another exotic species now widely distributed in south Florida. T. albipes shows more size variation than P. bourbonica. A column of ants that appear to be small, non-shining, size-variable P. bourbonica may be suspected of being T. albipes. The occurrence of T. albipes in southern Florida will not come as surprise to most myrmecologists. As early as 1922, Wheeler noted that this species was rapidly achieving pantropical distribution. In 1986 specimens were sent to Gainesville from an anonymous site in Homestead (Dade Co.), followed by report that the population had been eradicated. On this basis, Holldobler & Wilson (1990) suggested that T. albipes, which is established in California was possibly established in Florida. It is hard to predict the pest potential of T. albipes. In October, 1990, Dr. S. Koptur (Florida International University) sent series collected from conspicuous indoor infestation in south Miami. An anonymous reviewer of this paper reports that a whole residential neighborhood (indoors and outdoors) in Fort Lauderdale has been infested by T. albipes. This species appears to be strongly attracted to sweets, and might join the ubiquitous Paratrechina longicornis (Latreille) as nuisance around food and beverages. In other parts of the world, T. albipes has bad reputation for nurturing sap-sucking Homoptera (Samways et al. 1983, Nechols & Seibert 1985). There are numerous local native and exotic ants that visit honeydew-producing Homoptera, but my impression is that these ants with the possible exception of Camponotus abdominalis floridanus (Buckley), are not very effective guards. The Argentine ant, Iridomyrmex humilis (Mayr), involved in outbreaks of scale and mealybugs on citrus in Africa (Samways et al. 1983), is widespread but highly localized in south Florida, and the species is by no means the dominant ant that it is in many areas of the world. It is quite possible that T. albipes will remain, like I. humilis and many other exotic ants in Flonrda, local phenomenon of no major economic importance. This seems to be the status of T. albipes in Hawaii, where the entire ant fauna is exotic (Huddleston &