The Neotropical ant Anochetus mayri Emery (Fig. 1), a member of the subfamily Ponerinae, was first found in Florida in 1987 (Deyrup et al. 2000). This species is distinguished from somewhat similar Florida Odontomachus species by double-pointed petiolar scale (single point in Odontomachus spp.) and small size: maximum head + body length 4 mm (minimum head + body length of Odontomachus spp. 9 mm). The 1987 record, based on a single dealate queen from Homestead (Dade Co.), was supplemented by two specimens from south Miami (Dade Co.) in 1991. During the last decade I failed in several attempts to find additional specimens. The original site in Homestead, a pine stand near a tropical plant nursery, was obliterated by Hurricane Andrew in 1992. I had begun to wonder whether A. mayri still occurred in Florida.
An ant survey at the Pine Jog Environmental Learning Center in West Palm Beach (Palm Beach Co.) shows that, as of January, 2002, A. mayri is thriving, at least in one site. Collections were made from deep litter at the bases of pines and oaks. Litter samples, each about 1 liter, were brought back to the Archbold Biological Station and extracted with Berlese funnels. Out of the 36 samples collected, 27 produced at least one specimen of A. mayri. This species occurred together with the following ant species (number in parentheses is the number of co-occurrences with A. mayri; asterisk (*) denotes an exotic species): Brachymyrmex depilis (Emery) (3), Cyphomyrmex minutus Mayr (1), Hypoponera opacior (Forel) (2), Odontomachus brunneus (Patton) (1), Paratrechina guatemalensis (Forel)* (6), Pheidole floridana Emery (1), P. moerens Wheeler* (10), Pyramica eggersi (Emery)* (11), Solenopsis abdita Thompson (14), S. invicta Buren* (1), S. tennesseensis M. R. Smith (10), Strumigenys emmae (Emery)* (2), S. rogeri Emery* (6), Wasmannia auropunctata (Roger)* (8). Anochetus mayri clearly fits in well with the deplorably rich fauna of exotic ants in south Florida; half the species and more than half the individual associations are fellow exotics.
The trajectory of A. mayri in Florida ecosystems is impossible to predict at this point. It is widespread in the Caribbean and in Central and South America, but, in my limited experience, it is not a dominant species. It cannot be considered a major threat to native species in Florida as long as the Florida population is confined to urban and suburban habitats that are already somewhat disturbed and perfused with many other exotics. Anochetus mayri is a predaceous species that is not likely to become an economic pest. Although it is possibly capable of stinging humans, it is not aggressive or strongly defensive; live individuals picked out of the leaf litter ran about in my hand without attempting to sting. Its subterranean habitat further reduces its chances of interacting with humans. There is probably little chance of eradicating A. mayri from Florida, as it is a cryptic subterranean species with at least one large established population. It would be reasonable to periodically monitor areas of southeast Florida to determine whether this, or other exotic ant species, are undergoing explosive expansion. Although A. mayri is an unwelcome exotic species, it is also an interesting species whose biology is poorly known. One reason for publishing this note is to inform North American myrmecologists of a convenient population of A. mayri for scientific study.
Summary
A robust population of the exotic Neotropical ant Anochetus mayri Emery has been found in Palm Beach Co., Florida. The accompanying illustration should serve to distinguish this species from other ants found in the U.S. It has not yet been found in undisturbed habitats in Florida and seems to have little potential for becoming an economic pest.
