1. RIFA Mating Flights—> [Vertebrates]—> the RIFA Colony
  1. RIFA Mating Flights—> [Arthropods]—> the RIFA Colony

Pathways 27 and 28 are combined here because they describe a similar occurrence. Upon returning to the ground after mating flights, many founding queens (i.e., potential colonies) are consumed as food by vertebrates and arthropods because they are vulnerable and have little in the way of defense (Nickerson et al. 1975). Also, many alates (both male and female) have been observed to be caught and consumed by dragonfly (Odonata) predators immediately after becoming airborne from their home nest (Glancey 1981). The effect of predation on RIFA alates is considered to be quite substantial. In fact, Whitcomb et al. (1973) speculated that > 99% of female alates are killed by predators.

Among the vertebrate predators observed are many bird species including the Chimney Swift, Chaetura pelagica L.; the Tree Swallow, Iridoprocne bicolor Veillot; and Eastern Kingbirds, Tyrannus tyrannus (L.)(Whitcomb et al. 1973).

Arthropod predators can be divided into two groups, aerial predators and terrestrial predators. The only observed aerial arthropod predators are dragonflies (see Whitcomb et al. 1973 for a list). Terrestrial arthropod predators are of two types, surface predators, and subterranean predators. Surface predators normally were observed preying on newly-landed queens, whereas the subterranean predators killed queens that had already begun to burrow. Many species of ants were observed to be both surface and subterranean predators of RIFA reproductives. Among the more common ones were Conomyrma insana (Formicidae: Dolichoderinae) and workers from neighboring colonies of the RIFA (Whitcomb et al. 1973).

Literature Cited

Additional Literature

Glancy (1981)

Lockley (1995a)

Nickerson et al. (1975)

Nichols and Sites (1991)

Whitcomb et al. (1973)

  1. Silverfish (Thysanura)—> the RIFA Colony

Thysanurans are occasionally found in the RIFA colonies, strigilating the cuticle of workers and brood, and eating the brood. If detected by the ants, the ants quickly kill the parasites (Wojcik 1990).

Literature Cited

Additional Literature

Wojcik (1990)

  1. Millipedes (Diplopoda)—> the RIFA Colony

The diplopod, Calytodesmus schubarti Causey, is known to secrete a chemical that inhibits aggressive behavior by the RIFA so that it can feed on dead or injured ants and brood within the colony (Wojcik 1990).

Literature Cited

Additional Literature

Wojcik (1990)

  1. Beetles (Coleoptera)—> the RIFA Colony

Several species of the pselaphid, scabaeid, and staphylinid families of Coleopetera are known to prey on and/or are considered myrmecophiles of the RIFA (Wojcik 1990).

Pselaphidae are considered to be symphiles (true guests) of some Solenopsis spp., and are assumed to prey on brood (see Wojcik 1990 for review).

Two genera of Scarabaeidae with one or more species in each genus have been found with the RIFA, Rhyssemus neglectus Brown, Martinezia dutertrei Chalumeau, and other Martinezia species. Information on R. neglectus is limited, but M. duertrei is known to prey on ant larvae (Wojcik et al. 1991). Moreover, it was evidently introduced into the United States from South America with one of its fire ant hosts (S. richteri or S. invicta) (Wojcik et al. 1977).

Behavioral information is scarce on the species of the Staphylinidae, but data are available for Myrmecosaurus ferrugineus Bruch, which is a symphile of the RIFA and has been observed being fed by the workers of a colony (see Wojcik 1990 for review and citations therein).

Literature Cited

Additional Literature

Wojcik (1990)

Frank (1977)

Wojcik et al. (1977)

Summerlin (1978)

Wojcik et al. (1991)

Vander Meer and Wojcik (1982)


Wojcik (1980)

  1. Armadillos and Anteaters (Edentata)—> the RIFA Colony

Solenopsis ants make up sizeable proportions (ca. 1-70%) of the diet of Cyclopes, Tamandua and Myrmecophaga anteaters in northern South America (Montgomery 1985a and 1985b). In the southern United States, ants can make up over 50% of the average diet of long-nosed armadillo, Dasypus novemcinctus,with fire ants represented in the mix (Wirtz et al. 1985, Breece and Dusi 1985). Increased feeding on fire ants in South America following rains was related to increased surface availability of these ants (Montgomery 1985b). Feeding bouts of Myrmecophaga tridactyla were predominately less than 30 seconds per nest (Shaw et al. 1985); the bouts were terminated presumably by poor quality foraging resulting from either the aggressive attacks or the dispersal and hiding of the ants (Montgomery 1985b). A quantitative impact of such feeding on individual colonies is not documented, though substantial costs in terms of biomass (workers, reproductives and brood) and energy expenditures (defense and nest reconstruction) can be proposed. While individual mounds might be only browsed, impacts on local Solenopsis populations could be strong. Anteaters disturb and feed on large numbers of nests in their home ranges, as observed in South America (Montgomery 1985a, 1985b). In North America, Breece and Dusi (1985) found almost all of the fire ant mounds during their study had been disturbed by long-nosed armadillos.

Literature Cited

Additional Literature

Breece and Dusi (1985)


Montgomery (1985a)


Montgomery (1985b)


Shaw et al. (1985)


Wirtz et al. (1985)

  1. Microorganisms—> the RIFA Colony

Jouvenaz (1983) describes a microsporidia parasite of the RIFA, Thelohania solenopsae (Thelohaniidae), which has been identified in RIFA colonies throughout its range in South America. This parasite can infect adults of all castes. As of yet, it has not been demonstrated to be effective in controlling the RIFA. Other microorganisms listed as parasites of the RIFA include: another microsporidia of the genus Nosema; several bacteria of the genera Bacillus, Serratia and Pseudomonas; and various baculoviruses (Jouvenaz 1990).

Literature Cited

Additional Literature

Jouvenaz (1983)

Allen and Buren (1974)

Jouvenaz (1990)

Jouvenaz (1986)


Jouvenaz and Ellis (1986)


Pereira and Stimac (1992)


Williams et al. (1998)

  1. Nematodes—> the RIFA Colony

Nematodes in the families Steinernematidae and Heterorhabditidae have been under investigation as possible biocontrol agents. These nematodes can infect RIFA larvae, pupae, and alates, but workers were not susceptible. However, Drees et al. (1992) emphasize the need for more research on the host-parasite relationships before the efficacy of these nematodes can be understood.

Literature Cited

Additional Literature

Drees et al. (1992)

McInnes and Tschinkel (1995)


Nickle and Jouvenaz (1987)

  1. Fungi—> the RIFA Colony

Parasitic fungi of the RIFA, especially species of the genus Beauveria, which infect adult ants, have been given significant attention as prospective biocontrol agents. Oi et al. (1994) encourage continued research on the 447 isolate of B. bassiana for biocontrol, as deleterious effects have been demonstrated. Fungi of the genus Metarrhizium are also described parasites of the RIFA (Oi et al. 1994).

Literature Cited

Additional Literature

Oi et al. (1994)

Ba and Phillips (1996)


Jouvenaz and Kimbrough (1991)


Sanchez-Pena and Thorvilson (1992)

  1. Vegetation—> Parasitic Wasps (Hymenoptera)—> the RIFA Colony

The parasitic wasp mentioned in the above pathway is a eucharitid of the genus Orasema. Several species of Orasema are known parasites of Solenopsis fire ants, including Orasema crassa De Santis, O. aenea Gahan, and O. rapo Walker. These wasps lay eggs on vegetation, and the first instar larvae climb onto passing ants which carry them back to the colony. The wasp larvae then burrow into the brood of the host colony, and are nursed to adulthood in the colony. It is reported that the Orasema pupae are cared for in the same manner as the host brood, and in some instances, in preference to the host brood (see Wojcik 1990 for review and citations within).

Literature Cited

Additional Literature

Wojcik (1990)


  1. Parasitic Ants (Hymenoptera)—> the RIFA Colony

An ant that is parasitic on the RIFA is their congener, Solenopsis daguerri Santschi. Solenopsis daguerri is a known natural enemy of the RIFA in its native South America. Queens of the species S. daguerri enter RIFA colonies and produce offspring, which are taken care of by their hosts sometimes preferentially to their own brood (see Jouvenaz 1990 for review and citations therein).

Literature Cited

Additional Literature

Jouvenaz (1990)

Briano et al. (1997)


Calcaterra et al. (1999)


Pesquero et al. (1998)

  1. Mites (Acari)—> the RIFA Colony

The straw itch mite, Pyemotes tritici (Acari: Pymotidae), parasitizes all life stages of the RIFA, including the queen (Bruce and LeCato 1980). For these reasons, it has been investigated as a possible biocontrol agent, but research has not demonstrated that this mite has a significant enough impact on the RIFA to warrant further investigations (Jouvenaz and Lofgren 1986, Thorvilson and Phillips 1987).

Literature Cited

Additional Literature

Bruce and LeCato (1980)

Bass and Hayes (1976)

Jouvenaz and Lofgren (1986)


Thorvilson and Phillips (1987)


  1. a) Subject Colony—> Pheromone—> Phorid Flies (Diptera)—> the RIFA Colony
b) Heat Energy—> Phorid Flies (Diptera)—> the RIFA Colony

Some phorid flies from the genus Pseudacteon are known to parasitize the RIFA (Gilbert and Morrison 1997, Porter 1998, Morrison and Gilbert 1999). The flies, like the ants, are native to South America. Some species are attracted primarily to disturbed mounds (e.g., Gilbert and Morrison 1997), whereas others are found attacking at foraging trails (e.g., Orr et al. 1995). The attacking flies hover above the ants, and swoop down to inject their eggs into the thoraces of the adult ants. The larvae grow, then move into the head of the ant where they pupate, killing the ant. See pathways 5a and 6 for some of the known impacts that phorid flies have on the RIFA.

Literature Cited

Additional Literature

Gilbert and Morrison (1997)

Disney (1994)

Morrison and Gilbert (1999)

Fowler et al. (1995)

Orr et al. (1995)

Gilbert and Morrison (1997)

Porter (1998)

Orr et al. (1997)


Porter and Alonso (1999)


Porter et al. (1995b)


Williams et al. (1973)

  1. Another RIFA colony—> the RIFA Colony

This pathway merely represents the same idea as pathway 20b, but in this case it is the negative effect of brood raiding on the subject colony, by a different RIFA colony.

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