Worldwide spread of the difficult white-footed ant, Technomyrmex difficilis (Hymenoptera: Formicidae)

Technomyrmex difficilis FOREL, 1892 is apparently native to Madagascar, but began spreading through Southeast Asia and Oceania more than 60 years ago. In 1986, T. difficilis was first found in the New World, but until 2007 it was misidentified as Technomyrmex albipes (SMITH, 1861). Here, I examine the worldwide spread of T. difficilis. I compiled Technomyrmex difficilis specimen records from > 200 sites, documenting the earliest known T. difficilis records for 33 geographic areas (countries, island groups, major islands, and US states), including several for which I found no previously published records: the Bahamas, Honduras, Jamaica, the Mascarene Islands, Missouri, Oklahoma, South Africa, and Washington DC. Almost all outdoor records of Technomyrmex difficilis are from tropical areas, extending into the subtropics only in Madagascar, South Africa, the southeastern US, and the Bahamas. In addition, there are several indoor records of T. difficilis from greenhouses at zoos and botanical gardens in temperate parts of the US. Over the past few years, T. difficilis has become a dominant arboreal ant at numerous sites in Florida and the West Indies. Unfortunately, T. difficilis appears to be able to invade intact forest habitats, where it can more readily impact native species. It is likely that in the coming years, T. difficilis will become increasingly more important as a pest in Florida and the West Indies.