Fire Ants (Solenopsisspp.) and Their Natural Enemies in Southern South America

Abstract

We review the fire ant research conducted by the ARS-South American Biological Control Laboratory (SABCL) since 1987 to find a complex of natural enemies in southern South America and evaluate their specificity and suitability for field release as self-sustaining biological control agents. We also include those studies conducted by the ARS-Center for Medical, Agriculture, and Veterinary Entomology in the United States with the SABCL collaboration. Ecological and biological information is reported on local fire ants and their microsporidia, nematodes, viruses, phorid flies, eucharitid wasps, strepsiptera, and parasitic ants. Their biology, abundance, distribution, detrimental effect, field persistence, specificity, and phenology are discussed. We conclude that the objectives of the ARS program in South America are being achieved and that the pioneering studies have served to encourage further investigations in the United States and other countries and advanced the implementation of biological control programs to decrease imported fire ant densities and damage. Still, several promising organisms should be further investigated for eventual field release in the near future.

Microsporidia Biological Control Agents and Pathogens of Beneficial Insects

“…invictae was not as prevalent as K. solenopsae in the two imported fire ant species, S. invicta and S. richteri in South America (Briano et al 2012). Field populations of V. invictae-infected fire ants appear to be sporadic with wide and abrupt fluctuations in prevalence.…”

Effects of social immunity and unicoloniality on host–parasite interactions in invasive insect societies

“…For example, social insects keep their nest clean by removal of waste and dead bodies (Hart & Ratnieks 2001 and by integration of antimicrobial substances in the nest material. These can be either taken in from the environment, such as tree resin (propolis: Christe et al 2003;Simone-Finstrom & Spivak 2010), or constitute self-produced antimicrobials, such as gland substances (Brown 1968), venom (Baracchi, Francese & Turillazzi 2011) or even faeces (Rosengaus, Guldin & Traniello 1998). Diseased brood is often removed from the colony (hygienic behaviour, bees: Park, Pellett & Paddock 1939;Rothenbuhler 1964a;Boecking & Spivak 1999;Evans & Spivak 2010;ants: Ugelvig et al 2010) to prevent the parasite from completion of its life cycle.…”

“…Native to South America, the first records of invasive S. invicta populations were reported from the United States in the 1930s (Callcott & Collins 1996), and it has since then attained pest status in many parts of the world. A wide spectrum of parasites has been described from its native range, including parasitic phorid flies, nematodes, parasitic wasps, parasitic ants, fungi, microsporidia, bacteria and viruses (Briano, Calcaterra & Varone 2012). In contrast, only a few parasites have been found in the United States, despite extensive surveys (Porter et al 1997;Yang et al 2010).…”

Myrmecophily and Myrmecophagy of Attacobius lavape (Araneae: Corinnidae) on Solenopsis saevissima (Hymenoptera: Myrmicinae)

“…Together with other natural enemies (Briano et al, 2012), A. lavape preys on fire ants and helps to keep a low colony density in South America. In the southern United States, where S. invicta was accidentally introduced without natural enemies (Porter et al, 1997), the colony density is 16 times higher than S. saevissima density found in Morrinhos (12.95 ± 6.48 colonies/ha), but the relationship of this low density to the presence of A. lavape needs to be further evaluated.…”