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Nebraska Cooperative Fish & Wildlife Research Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications Unit

2001

Red Imported Fire Ants: Impact on Biodiversity

Daniel P. Wojcik U.S. Department of Agriculture

Craig R. Allen U.S. Geological Survey, [email protected]

Richard J. Brenner IFA & HI Research Unit

Elizabeth A. Forys Eckerd College

Donald P. Jouvenaz U.S. Department of Agriculture

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Wojcik, Daniel P.; Allen, Craig R.; Brenner, Richard J.; Forys, Elizabeth A.; Jouvenaz, Donald P.; and Lutz, R. Scott, "Red Imported Fire Ants: Impact on Biodiversity" (2001). Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications. 47. https://digitalcommons.unl.edu/ncfwrustaff/47

This Article is brought to you for free and open access by the Nebraska Cooperative Fish & Wildlife Research Unit at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Daniel P. Wojcik, Craig R. Allen, Richard J. Brenner, Elizabeth A. Forys, Donald P. Jouvenaz, and R. Scott Lutz

This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/ ncfwrustaff/47 Published in AMERICAN ENTOMOLOGIST Volume 47, Number 1 (Spring 2001).

T he red imported , Solenopsisinvicta (APHIS)added 55 counties in six statesto the quar- Buren (hereafterreferred to as imported fire antine area (Arnoldi 1998, Schwalbe1998). Com- ant), long considereda regional problem, is mercialpesticides are available,but useof traditional receiving renewed attention nationwide, with in- toxicants is costly. Most are not registeredfor large festations found in Arizona, Maryland, Nevada, acreageand potentially have adversecollateral im- New , and Virginia (Mitchell 1996). Re- pacts, especiallywhen used in recreationalareas or cently,infestations discoveredin severalregions of environmentally sensitive locations. The federal California caused great public concern (Brennan quarantine that restricts movement of untreated 1999, Schrader 1999). Initially, infestations ap- nursery stock into areas not infested by fire ants peared to be isolated in almond groves in Kern adds an additional cost for nurserymenand regu., County; presumably these infestations originated latory agencies.Thompson et al. (1995) estimated from bee hives transported interstate for the pur- the economic impact (medical, damage,and pesti- pose of pollinating crops. Separately,ornamental cide costs) of imported fire ants in the infested plants arriving in Las Vegas,NY; were infestedwith southernstates to be in excessof $1 billion annually. fire ants, and records showed that the point of In the early 1970s, a polygynous (multiple origin was a nursery in Orange County, CA. Fur- queen) form of S. invicta was detected, and this ther inspectionsrevealed infestations in over 16,000 form has become increasingly more common dur- acres of Orange County. Finally, infestations were ing the past two decades(Glancey et al. 1987, Por- identified in some desertirrigated agricultural re- ter et al. 1991). Population densities per unit area gions of the Coachella Valley in Riverside County, of this form are two to three times greater than the

CA. Subsequently,a toll-free telephone number monogynous form (Macom and Porter 1996), was established for reporting fire ant mounds in which exacerbatesthe difficulties and coststo man- the state of California (800-491-1899). age this pest and also increasesrisks to humans These infestations are a continuation of a pro- and . cess that began when the imported fire ant was Although imported fire ants are generalpreda- introduced inadvertently into North America in tors and scavengers,they are highly aggressivewhen the late 1930s. By 1999, infestations totaled over their nests are disturbed and cause painful stings 121 million hectares (310 million acres) in Ala- to humans, pets, domestic animals, and wildlife. bama, Arkansas,, Georgia,, Mis- Approximately 30% of the people in the infested sissippi, North Carolina, Oklahoma, South areasare stung eachyear; of these,approximately Carolina, Tennessee,Texas, and in Puerto Rico. 1 % may develophypersensitivity to the ant's venom Although the rate of spreadhas diminished during and require some type of medical care with costs the past decade,continued expansion-as has oc- running into the inillions of dollars (Vinson 1997). curred in California-is expectednorthward along Today, in the fire ant infested region, more immu- both continental coasts and southward into notherapy is prescribed for fire ant hypersensitiv- Mexico and the Caribbean. In fact, in 1998, the ity than for any other hymenopterous allergy USDA's Plant Health Inspection Service (Freeman1997).

AMERICANENTOMOLOGIST. Spring 2001 16 Vinson (1997) reviewed the introduction and Linepithema humile (Mayr) (Glanceyet al. 1976), initial expansion of imported fire ants into North and 18 others (Porter and Savignano1990). America. He discussedmany details of their biol- In contrast, some ant specieshave survived and ogy, behavior, and impacts but included little dis- even increased in numbers and distribution after cussion of their effects on biodiversity. Therefore, imported fire ant invasion, particularly in this article we discuss the impacts of the im- Dorymyrmex spp., Monomorium minimum ported fire ant on biodiversity, an under-empha- (Buckley), and Forelius pruinosus (Roger) sizedarea that currently is receivingmore attention. (Summerlin et al. 1977, Camilo and Philips 1990, Jusino Atresino and Phillips 1994). Wojcik (1994) Impact of Fire Ants on Biodiversity monitored ant populations with bait traps on The , of Invertebrates transectsfor 21 years in Gainesville,FL, and found Direct Impact on Invertebrates. Imported fire that S. invicta gradually increasedfrom 0 to 43.3 % conclusion was ants feed on a wide variety of invertebrates (Wil- of the occurrences(collections per sampling date) imported fire ants son and Oliver 1969, Lofgren 1986, Vinson 1994). (maximum 55.8%) and 63.1 % of the specimens attacked, killed, and .They have receivedsome attention as beneficialin- (maximum 74.3%) (Fig. 1). Positive correlations sectsbecause they are predators of some pestspe- in percentoccurrences with S. invicta populations consumed any cies [e.g., lone star tick, Amblyomma americanum were shown by three introduced ant species invertebrate that (L.) (Burns and Melancon 1977); tobacco bud- [Paratrechina longicornis (Latreille), Pheidole would not defend worm, He/iothis virescens(F.) (McDaniel and Ster- moerens Wheeler, and Tetramorium simillimum ling 1982); sugarcane borer, Diatraea sacchara/is (Smith)], and one native species[Odontomachus itself adequately or (F.) (Reaganet al. 1972); boll , brunneus (Patton)]. Negative correlations in per- escape. grandis grandis Boheman (Sterling 1978); and horn fly, Haematobia irritans (L.) (Summerlinet al. 1984a)]. Their effects on nonpest speciesare less well known, but they have been shown to affect somebeneficial negatively (e.g., the braconid parasitoid Cardiochi/es nigriceps Viereck [Lopez 1982], dung-inhabiting scarabbeetles [Summerlin et al. 1984b], releasedbiocontrol agentsand polli- nators [Nordlund 1988, Williams et al. 1986], the aphidiid parasitoid Lysiph/ebustestaceipes Cresson [Vinson and Scarborough 1991], and dung-inhab- iting predatory [Hu and Frank 1996]). The effects of imported fire ants on invertebrate faunas in nonagricultural habitats have beenstud- ied in central Texas. Hooper (1976) showed that these ants reduced isopod density but not Gryll~ cricket density. Porter and Savignano(1990) found that after an invasion by polygyne colonies, some (isopods,certain mites,tumble bug scar- abs)declined significantly, whereasothers (ground crickets, a brachypterous cockroach, a symbiotic scarab)increased. Overall, the speciesrichness of non-antarthropods was 30% lower in infestedsites, and numbers of individuals were 75% lower. Ricks and Vinson (1970) demonstratedthat imported fire ants preferred somespecies of arthropods to others M--$- _.s. l -"...$ _-$ S '-'-'-S---I- cM_5 ..0. -"- J- -" S- ._$ 1m 1m 74 7S ,. 1m 1m 1979 ItIO IMI 1M2 ..IS ..., II ..to 91 t2 but would feed on any . The generalconclu- sion was that imported fire ants attacked, killed, .and consumed any invertebrate that would not de- fend itself adequatelyor escape. Direct Impact on Other Ant Species.The effects of imported fire ants on other ant specieshave .been demonstrated in several studies, but direct predation on the nests of these other specieshas beenobserved only rarely (Hook and Porter 1990). The native fire ants, S. geminata (F.) and S. xyloni McCook, have beendisplaced as the invading im- ported specieshas spread acrossthe southeastern It , M.--'- -.!i .J _tL..a- ~ JL,..s ~ --J- 1LJ. --°- .14_'_11 _1__' 1m ,m 74 n 76 1m '978 1m I'" "" 1m ..asl6 "' 18 ..to 'I n (Wilson and Brown 1958, Roe 1973, --MONTHS Porter et al. 1988, Porter 1992, Wojcik 1994). Other speciesdisplaced by imported fire ants in- Fig. 1. Percent occurrences (collections per sampling date) (A), percent specimens (B), and number of sites (C) for major species of ants clude Pheidole tepicana Pergande,P. crassicornis collected on the Gainesville, FL, transect from March 1972 to September tetra Wheeler (Camilo and Philips 1990), 1992. Figure redrawn from Wojcik 1994.

AMERICANENTOMOLOGIST. Volume 47 Number 1 17 Impact on EndangeredCave Invertebrates. Im- ported fire ants are an important predator of cave invertebrates,including severalendangered species (pseudoscorpions, harvestmen, spiders, ground beetlesand pselaphid beetles)in Texas(Elliott 1993). Spatially based studies conducted in cooperation with the Department of the Interior, Fish and Wild- life Service (D.P.W:and R.].B., unpublished data), showed that the ants not only dominate food baits around the caves (Fig. 2) but also foraged deeply into the cavesfor prey. A special concernwas that omnivorous caveinvertebrates foraging outside the cavesat night could consumepesticide-treated fire ants, which might prove lethal to the endangered species.Fortunately, laboratory studiesshowed that the activeingredient in Amdro bait (hydramethylnon) did not affect cavecrickets forced to feed on Amdro- killed ant cadavers.Temporal separationof forag- ing activities for target and nontarget organisms allows bait treatment of the areassurrounding the cavesduring the daylight hours when fire ants are foraging but cave invertebratesare not. Fig. 2. Distribution of foraging outside a cave near Austin, TX. Multiple ant species baits placed in a 3-meter grid (12 ' 12) at 2100 hours and counted at Impact on invertebrates of the Florida Keys. 10-minute intervals. Vertical bar and contour lines indicate numbers of fire ants counted Imported fire ants first were recorded in the Florida for given time period. Cave entrance indicated by blue polygon. Keys in 1976 (Callcott and Collins 1996) but were considered to be restricted to disturbed areas (Deyrup et al. 1988, Porter 1992). However, dur- cent occurrenceswere shown by one introduced ing a Keys-wide survey in 1996, the ant was col- speci&S(Cardiocondyla emeryi Forel), and 10 na- lected on 10 of the 14 major keys (Forys et al. tive species [Crematogaster ashmeadi Mayr, 1997) and in every major habitat type including Dorymyrmex bureni (Trager), Forelius pruinosus hardwood hammocks, pinelands, salt and fresh- (Roger),Monomorium viride Brown, Paratrechina water marshes,and disturbed areas(e.g., roadsides, vividula (Nylander), Pheidole dentata Mayr, P. parking lots). Its presencein the tropical hardwood floridana Emery,P. metallescensEmery, P. morrisi hammocks was of particular concern becausesev- Forel, S. geminataJ. Only two native species (S. eral speciesof rare, endemic invertebrates occur in geminata and P. dentata) originally occurred in this habitat. The ant was found up to 40 m into the numbers sufficient for changesto be detected in hammock (Forys et al. 1997) on terrestrial and short-term studies of 3-4 years (R = 0.782 and arboreal bait transects. 0.543, respectively). The Schaus swallowtail, Papilio aristodemus ponceanus Schaus,is a rare burterfly that occurs only in tropical hardwood hammocks in the north- ernmost Florida Keys and the east coast of south- ern Florida (Fig. 3); it is listed as endangered at both the state and federal levels (Emmel 1986). Although portions of this habitat are protected for the swallowtail, the butterfly's populations have continued to decline. Adults lay their eggs on a selectgroup of trees,primarily wild lime tree (Zan- thoxylum fagara), that occur in hardwood ham- mocks in portions of Monroe and Dade County, Florida (Emmel1986). The Florida Gameand Fresh Water Fish Commission funded our researchbe- ~ cause of the concern with the vulnerability of the immature stagesto fire ant predation. A";Y Using the orangedog, Papilio cresphontes /- Cramer, as a surrogate for the endangeredbutter- fly in experiments, eggs, larvae, and pupae were exposed on an enclosedsmall wild lime tree acces- ~ sible to an imported fire ant colony (Forys et al. 1997). The fire ants preyed on all of the swallow- -.. tail life stages.In fact, fire ants discoveredall stages Fig. 3. Location in the Florida Keys of Schaus swallowtail, Papilio faster than an alternate meat food source. Field aristodemus ponceanus, and Stock Island tree snail, Orthalicus reses studies are underway to determine the impact on reses, habitat. the butterfly by removing S. invicta from the habi-

18 AMERICANENTOMOLOGIST. Spring 2001 sources increases when brood is present in the colony (Sorensenet al. 1983) becausehigh protein foods are neededfor larval growth. Fire ant brood production occurs primarily in the warmer months and coincides with the breeding periods of most vertebrates. Direct Impacts on Mammals. Interactions be- tween imported fire ants and mammals is poorly documented.The death of live-trapped smallmam- mals from fire ant predation has been observed (Masserand Grant 1986, Flickinger 1989),includ- ing the altricial young of many species.Hill (1970) quantified the loss of newborn cottontail rabbits, Sylvilagusfloridanus (Allen), to fire ants in 200 by 200 ft enclosuresand observed mortality ranging from 33 to 75%. Allen et al. (1997a) documented increased numbers of white-tailed deer fawns, Odocoileus virginianus (Zimmerman), in large plots on which fire ant populations had beenre- duced.These increases probably were the result of Fig. 4. Stock Island tree snail, Olthalicus reses reses a reduction in direct (e.g.,stinging leadingto blind- (conical shell up to 75 mm length), aestivating on a ness)and indirect (e.g., increasedmovement lead- tree in the Keys. Photograph by Matt Schrock. ing to increasedvulnerability to predators)effects. Direct Impacts on Reptiles and Amphibians. tats using toxic baits (E.A.F., C.R.A., and D.P.W., Oviparous reptiles and amphibians may be vul- unpublished data). nerable to fire ant populations, but no experimen- The Stock Island tree snail, Orthalicus reses tal evidenceexists. Mount (1981) was the first to reses (Say) (Fig.4), is listed by the U.S. Fish and speculatethat fire ants might have a strong impact production occurs Wildlife Serviceas threatened and by the State of on a wide diversity of herpetofauna. Kauffeld Florida as endangered(Forys et al. 1996). Histori- (1957), D.P.]. (unpublished data), and Bartlett primarily in the cally, it was found in severalhardwood hammocks (1997)noted the dramatic declinein the local popu- warmer months throughout Stock Island and Key West (Fig. 3), lation of the peninsular intergrade kingsnake and coincides although it has beenextinct in the wild since 1992 (Lampropeltis getula floridanus Blanchard x L. g. (Forys et al. 1996). Stock Island tree snails spent KeturaL.) on PaynesPrairie Statepreserve, Alachua with the most of the year aestivating on trees, descending County,FL. coinciding with the invasionand rapid breedingperiods of for a few hours during the wet season (May to population rise of polygynous imported fire ants. October)to lay eggs4-5 cm deepin treelitter (Deisler Mount et al. (1981) documented the consump- most vertebrates. 1987). Predationby imported fire ants, either when tion of the eggs of the six-lined race runner, snails are on the treesand ground, was thought to Cnemidophorus sexlineatus (L.), by the imported be a major factor in the snail's extinction (Forys et fire ant. This lizard was common on the premises al. 1996). of the GainesvilleUSDA laboratory before fire ants To assessthe vulnerability of Stock Island tree infested the property (D.P.]., unpublished data). snails to imported fire ants, an experiment was Mortality from the stings of the imported fire ant conducted using Florida tree snails, Liguus was observedin adults of the box turtle Terrapene fasciatus (Miiller), from north Key Largo as surro- carolina triunguis (Agassiz)(Montgomery 1996) gatesfor the endangeredspecies (Forys et al. 1997). (Fig. 5A), an unidentifiable snake(C.R.A., unpub- In laboratory experiments, 19 of the 22 tree snails lished data) (Fig. 5B), and young of the toad Bufo were killed by the fire ants within 3 days, 12 while houstonensis(Sanders) (Freed and Neitman 1988). activelyforaging and 7 while aestivating.Field stud- When fire ants are presentin nestsof the alligator, ies are underway to determine the impact on snail Alligator mississippiensis(Daudin), hatching alli- populations by removing S. invicta from the habi- gator young are subject of predation (Allen et al. tats using toxic baits (E.A.F., C.R.A., and D.P.W., 1997b). Nesting Pseudemysnelsoni (Carr) turtles unpublished data). arevulnerable when pipping, with mortality ashigh as 70% (C.R.A. and D.P.W., unpublished data). Impact of Fire Ants on Biodiversity There has been considerable concern and debate of Vertebrates over the potential impact of fire ants on nesting Direct Impacts on Vertebrates. Information on sea turtles, but, again, no experimental evidence the direct impact of imported fire ants on native exists. Wilmers et al. (1996) documented an in- vertebratesis limited (Allen et al.1994). However, creasingpresence of fire ants in seaturtle nests on it is known that these ants prey on altricial (help- remote island beaches in the Florida Keys, and less immature) young, pipping young (breaking Moulis (1996) found a 15% decreasein hatchling out of the eggshell), and, rarely, adults. They are release rate for loggerhead sea turtles, Caretta attracted to sourcesof proteins, sugars,lipids, and caretta (L.), emerging from nestsinfested with fire moisture (Vinson et al. 1967). Feeding on protein ants as compared to uninfested nests. These ob- 10 AMERICANENTOMOLOGIST. Volume 47 Number 1 Direct Impacts on Birds. Fire ants may be a preda- tor on many species of birds. Recent work sug- gests that chicks of northern bobwhites, Colinus virginianus (L.), are susceptibleto fire ants (Allen et al. 1995). The national decline in northern bob- white numbers has beenlinked largely to declines in habitat availability and quality. Becausefire ants are adapted to disturbed areas (Vinson 1997), the issueof habitat quality decline and invasion by fire ants are inseparable,making their impact additive. Ground nesting species, such as the least tern, Sterna antillarum Lesson,are particularly vulner- able to fire ants (Lockley 1995). Negative impacts may be especiallysevere in colonial breeding spe- cies. For example,waterbird nest mortality was as high as 100% on fire ant infested barrier islands (Drees 1994), although mortality varied and was lower for early-nesting birds. Cliff swallows, Hirundo pyrrhonota (Vieillott), experienced de- creasedbrood survival in nesting colonies exposed to foraging fire ants (Sikes and Arnold 1986). However, where negative effects on breeding suc- cesshave been documented, fire ant populations have beenreduced to acceptablelevels with proper insecticidetreatments (Drees 1994, Lockley 1995). Fig. 5. (A) Remains of box turtle carcass killed and Indirect Impacts on Vertebrates. The indirect fed upon by red imported fire ants in southeastern effects of imported fire ants on native vertebrates Texas. (B) Remains of snake killed and fed upon by red imported fire ants in southeastern Texas.The may be more important than direct predation. Allen snake was killed and skeletonized over night in et al. (1998) found that indirect impacts include screen trap. Identification was not possible because reduced survival and weight gain resulting from the skull had been destroyed by the ants. Original envenomization, behavioral changes in foraging photos by C. R. Allen. patterns and habitat use,reduced food availability, community-level changes resulting from ttophic servations suggestthat potential impacts are con- cascades,and system-levelchanges resulting from siderable, although inherent difficulties with ma- the impact of these ants on ecological processes. nipulations of large-scaleexperimental populations Reduced survival resulting from fire ant stings in general,and reptile community sampling in par- has beendocumented only for northern bobwhite ticular, make it difficult to assessthe impacts of (Giuliano et al. 1996). Fire ant venomis unlike that theseants on herpetological communities. of most other Hymenoptera, consisting primarily of alkaloids with hemolytic, cytotoxic, and necrotic properties (Fox et al. 1982, deShazo et al. 1990). The loss of digits and appendagesby small verte- brates,as well as blinding, may result from fire ant envenomization,and se~ondaryinfection is possible. Reduced weight gain resulting from the stings of imported fire ants has beendocumented for both northern bobwhite (Giuliano et al.1996) and Ameri- can alligators (Fig. 6) (Allen et al. 1997b). Reduced weight gain in juvenilesmay lower long-termsurvival and reproduction (Brockelman 1975, Grant 1991). Behavioral changes,including altered activity (Pedersen et al. 1996) and foraging patterns (Holtcamp et al. 1997), have beendocumented for small mammals and birds. Changes in foraging and activity patterns likely result from the irrita- tion associatedwith fire ant stings.Whiting (1994) Fig. 6. Effects of red imported fire ant stings on weight gain of hatching American reported the abandonment of a nesting attempt by alligators. Fire ants regularly nest in alligator nests and will attack alligator eggs the Texas river cooter due to the irritation associ- when eggshell cracking occurs during hatching. The ants will enter the eggs and ated with stings. sting and feed upon the unhatched alligators. Alligator eggs ready to pip were Imported fire ant infestations can affect habitat placed in artificial nests infested with fire ant colonies. Hatchlings were removed use by vertebrates (Smith et al. 1990, Killion and after successfully emerging from the eggs. Hatchling alligators normally lose weight after hatching, before they start feeding. Stung alligators did not gain weight Grant 1993, Killion et al. 1995, Holtcamp et al. at a rate comparable to unstung check animals, which would put them at a distinct 1997). For example, vertebrates may avoid areas disadvantage in nature. Original figure by C.R.A.; data from Allen et al. 1997b. heavily infested with fire ants becauseof the irrita-

20 AMERICANENTOMOLOGIST. Spring 2001 tion associatedwith fire ant stings,and may expe- No. 1448-00002-95-0749; and, in part, by the rience altered food availability (i.e., insects)result- Nongame Division of the Florida Game and Fresh ing from fire ant infestation. Where the optimal Water Fish Commission Project Number: habitat of a native speciesand high fire ant densi- NG95-018. The South Carolina Cooperative Fish ties occur together, displacementof the vertebrate and Wildlife ResearchUnit is supported jointly by to suboptimal habitat has a negative population- a cooperative agreementamong the USGS/BRD, level impact on the vertebrate species. the South Carolina Department of Natural Re- Reductions in available food need not result in sources,Clemson University, and the Wildlife Man- displacement of vertebrates but may, nonetheless, agementInstitute. reducevertebrate populations. Fire ant impacts on insect speciesand communities are reasonablywell References Cited documented (Porter and Savignano 1990, Morris Allen, C. R., S. Demaris, and R. S. Lutz. 1994. Red and Steigman 1993), although there is a bias to- imported fire ant impact on wildlife: an overview. ward determining impacts on speciesof economic, Tex. J. Sci. 46: 51-59. rather than ecological, importance. In insectivo- Allen, C. R., R. S. Lutz, and S. Demaris. 1995. Red rous vertebrates,reduced food availability due to imported fire ant impacts on northern bobwhite the presenceof imported fire ants may be expected populations. Ecol. Appl. 5: 632-638. Allen, C. R., S. Demarais,and R. S. Lutz. 1997a. Effects to both increase territory (or home range)and de- of red imported fire ants on recruitment of white- creaserecruitment. In the extremecase of food spe- tailed deer fawns. J. Wildl. Manage. 61: 911-916. cialization where the food source is affected Allen, C. R., K. G. Rice, D. P. Wojcik, and H. F. Percival. negatively by fire ants, population collapses may 1997b. Effect of red imported fire ant envenomiza- occur. This is occurring with the Texashorned liz- tion on neonatal American alligators. J. Herpetol. ard, Phrynosoma cornutum (Harlan), in south and 31: 318-321. easternTexas. This lizard feeds primarily on ants Allen, C. R., R. S. Lutz, and S. Demarais. 1998. Eco- of the genus Pogonomyrmex, whose populations logical effects of the invasive non- indigenous ant, The loss of dig~ are reduced by the imported fire ant (Donaldson et Solenopsisinvicta, on native vertebrates: the wheels al. 1994, Jusino Atresino and Phillips 1994). The on the bus.Trans. N. Am. FishWildl. Conf. 63: 56-65. appendages by small Arnoldi, J.M. 1998. Imported fire ant quarantined ar- lizard largely has been eliminated from the areas eas. Fed. Reg. 63: 4151-4154. vertebrates, as well infested with fire ants (Price 1990). A thriving in- Bartlett, D. 1997.40 years of thoughts on PaynesPrai- as blinding, may troduced disjunct lizard population in Escambia rie. Reptiles 5(7): 68, 70-73. County, FL, declined and disappeared after the Brennan,P. 1999. NatUre reservesbrace for fire ants. Or- result from fire ant imported fire ant becameestablished and fire ant angeCounty Reg. 25 February 1999, Metro pp. 1-2. envenomization, populations increased(D.P.]., unpublished data). Brockelman, W. Y. 1975. Competition, the fitness of offspring, and optimal clutch size. Am. Nat. 109: and secondary Summary 677-699. infection is possible. Thesestudies document the actualand suspected Burns, E. C., and D. G. Melancon. 1977. Effect of impacts of fire ants on endangeredvertebrates and imported fire ant (Hymenoptera: Formicidae) inva- sion on lone star tick (Acarina: Ixodidae) popula- invertebrates and their habitats. Clearly, from an tions. J. Med. Entomol. 14: 247-249. ecologicalperspective, reducing fire ant populations Callcott, A.-M. A., and H.L. Collins. 1996. Invasion would help restore the natural biodiversity of ani- and range expansion of red imported fire ant (Hy- mals that existed before the fire ant invasion. The menoptera: Formicidae) in North America from imported fire ant is having greater ecological ef- 1918-1995. Fla. Entomol. 79: 240-251. fects than have beendocumented previously. Both Camilo, G. R., and S. A. Philips (sic), Jr. 1990. Evolu- the research reviewed here and the research in tion of ant communities in responseto invasion by progress indicate that the ecologicaleffects of im- the fire ant Solenopsisinvicta, pp. 190-198. In R. K. ported fire ants are among the more important Vander Meer, K. Jaffe, and A. Cedeno [eds.], Ap- negative results of the presence of these ants in plied myrmecology, a world perspective. Westview, Boulder, CO. North America. Deisler, J. 1987. The ecology of the Stock Island tree snail Orthalicus resesreses (Say). Bull. Fla. St. Mus. Acknowledgments 31: 107-144. The authors thank D. E. Milne (Centerfor Medi- deShazo,R. D., B. T. Butcher, and W. A. Banks. 1990. cal, Agricultural and VeterinaryEntomology, USDA- Reactions to the stings of the imported fire ant. N. ARS [CMAVE]) for analyzing the data and Engl. J. Med. 323: 462-466. preparing Figure 2. The manuscript was improved Deyrup, M. A., N. Carlin, J. Trager, and G. Umphrey. greatly by the critical reviews of W. A. Banks, T. 1988. A review of the ants of the Florida keys. Fla. Fukuda, C. S. Lofgren, R. S. Patterson, and J. Entomol. 71: 163-176. Donaldson, W., A. H. Price, and J. Morse. 1994. The Sivinski (all from CMAVE). Researchreported in current status and future prospects of the Texas this article was funded, in part, by the Department horned lizard (Phrynosoma cornutum) in Texas.Tex. of Defense,Pollution PreventionProject No. 1053, J. Sci. 46: 97-113. Strategic Environmental Researchand Develop- Drees,B. M. 1994. Red imported fire ant predation on ment Program (SERDP), and under EPA-USDA nestlings of colonial waterbirds. Southwest. Interagency Agreement No. DW12937500-01-0; Entomol. 19: 355-359. in part, by the Department of Interior, U.S. Fish Elliott, W. R. 1993. Fire ants and endangered cave and Wildlife ServiceFWS Interagency Agreement invertebrates: a control and ecological study.

AMERICANENTOMOLOGIST. Volume 47 Number 1 21 Revised Final Report. EndangeredResources Branch, assessingthe impact of imported fire ants on small Resource Protection Division, TexasParks and wild- mammals. Southwest. Nat. 38: 393-396. life Department, Austin, TX. Killion, M. J., W. E. Grant, and S. B. Vinson. 1995. Emmel, R. C. 1986. Status survey and habitat require- Response of Baiomys taylori to changes in density ments of Florida's endemic Schaus swallowtail but- of imported fire ants. J. Mammal. 76: 141-147. terfly. Final Report GFC-84-028. Florida Game and Lockley, T.C. 1995. Effect of imported fire ant preda- Fresh Water Fish Commission, Tallahassee,FL. tion on a population of the least tern -an endan- Flickinger, E. L. 1989. Observation of predation by red gered species.Southwest. Entomol. 20: 517-519. imported fire ants on live-trapped wild cotron rats. Lofgren, C. S. 1986. The economic importance and Tex. J. Sci. 41: 223-224. control of imported fire ants in the United States,pp. Forys, E. A., P.A. Frank, and R. S. Kautz. 1996. Recov- 227-256. In S. B. Vinson [ed.], Economic impact and ery Actions for the Lower Keys marsh rabbit, silver control of social insects. Praeger,New York. rice rat, and Stock Island Tree Snail. U.S. Fish and Lopez, J. D., Jr. 1982. Emergence pattern of an over- Wildlife Service,Vero Beach,FL. wintering population of Cardiochiles nigriceps in Forys, E. A., C. R. Allen, and D. P. Wojcik. 1997. The central Texas. Environ. Entomol. 11: 838-842. potential for negative impacts by red imported fire Macom, T.E, and, S.D. Porter. 1996. Comparison of ants (Solenopsis invicta) on listed herpetofauna, polygyne and monogyne red imported fire ants (Hy- mammals, and invertebrates in the Lower Florida menoptera: Formicidae) population densities. Ann. Keys. NG95-018. Florida Game and Fresh Water Entomol. Soc. Am. 89: 535-543. Fish Commission, Tallahassee,FL. Masser,M. P.,and W. E. Grant. 1986. Fire ant-induced Fox, R. W., R. F. Lockey, and S. C. Bukantz. 1982. trap mortality of small mammals in East-central Neurologic sequelaefollowing the imported fire ant Texas. Southwest. Nat. 31: 540-542. sting. J. Allergy Clin. Immunol. 70: 120-124. McDaniel, S. G., and W. L. Sterling. 1982. Predation Freed,P. S., and K. Neitman. 1988. Notes on predation of Heliothis virescens (F.) eggs on in East on the endangeredHouston toad, Bufo houstonensis. Texas. Environ. Entomol. 11: 60-66. Tex. J. Sci. 40: 454-456. Mitchell, J.C. 1996. A burning dilemma for wildlife. Freeman, T.M. 1997. Hymenoptera hypersensitivity in Virginia Wildl. 57(4): 9-13. an imported fire ant endemic area. Ann. Allergy Montgomery, W. B. 1996. Predation by the fire ant, Asthma Immunol. 78: 369-372. Solenopsis invicta, on the three-toed box turtle, Giuliano, W. M., C. R. Allen, R. S. Lutz, and S. Demaris. Terrapene carolina triunguis. Bull. Chicago 1996. Effects of red imported fire ants on northern Herpetol. Soc. 31: 105-106. bobwhite chicks. J. Wildl. Manage. 60: 309-313. Morris, J. R., and K. L. Steigman. 1993. Effects of Glancey, B. M., D. P. Wojcik, C. H. Craig, and J. A. polygyne fire ant invasion on native ants of a black- Mitchell. 1976. Ants of Mobile County, AL, as land prairie in Texas. Southwest. Nat. 38: 136-140. monitored by bait transects. J. Ga. Entomol. Soc. Moulis, R. A. 1996. Predation by the imported fire ant 11: 191-197. (Solenopsisinvicta) on loggerheadsea turtle (Caretta Glancey,B.M., J.C.E. Nickerson, D. Wojcik, J. Trager, carella) nests on Wassaw National Wildlife Ref- W.A. Banks, and C. T. Adams. 1987. The increasing uge, Georgia. Chelonian Conserv. Bioi. 2: 105-106. incidence of the polygynous form of the red im- Mount, R. H. 1981. The red imported fire ant, ported fire ant, Solenopsis invicta (Hymenoptera: Solenopsis invicta (Hymenoptera: Formicidae), as Formicidae), in Florida. Fla. Entomol. 70: 400-402. a possible serious predator on some native south- Grant, M. C. 1991. Relationships between egg size, eastern vertebrates: direct observations and subjec- chick size at hatching, and chick survival in the tive impressions. J. Ala. Acad. Sci. 52: 71-78. whimbrel, Numenius phaeopus. Ibis 133: 127-133. Mount, R. H., S. E. Trauth, and W. H. Mason. 1981. Hill, E. P. 1970 (1969). Observations of imported fire Predation by the red imported fire ant, Solenopsis ant predation on nestling cottontails. Proc. South- invicta (Hymenoptera: Formicidae), on eggs of the east. Assoc. Game Fish Comm. 23: 171-181. lizard Cnemidophorus sexlineatus (Squamata: Holtcamp, W. N., W. E. Grant, and S. B. Vinson. 1997. Teiidae). J. Ala. Acad. Sci. 52: 66-70. Patch use under predation hazard: Effect of the red Nordlund, D. A. 1988. The imported fire ant and natu- imported fire ant on deer mouse foraging behavior. rally occurring and released beneficial insects, pp. Ecology 78: 308-317. 51-54. In S. B. Vinson and J. Teer [eds.], The im- Hook, A. W., and S. D. Porter. 1990. Destruction of ported fire ant: assessmentand recommendations. harvester ant colonies by invading fire ants in South- Proceedings, Governor's Conference. Sportsmen central Texas (Hymenoptera: Formicidae). South- Conservationists of Texas, Austin, TX. west. Nat. 35: 477-478. Pedersen,E. K., W. E. Grant, and M. T. Longnecker. Hooper, M. W; 1976. The effectsof the imported fire ant, 1996. Effects of red imported fire ants on newly- Solenopsisinvicta, on the eastTexas com- hatched northern bobwhite. J. Wildl. Manage. 60: munity. M.S. thesis, University of Texas at Austin. 164-169. Hu, G. Y., and J. H. Frank. 1996. Effect of the red Porter, S. D. 1992. Frequency and distribution of imported fire ant (Hymenoptera: Formicidae) on polygyne fire ants (Hymenoptera: Formicidae) in dung-inhabiting arthropods in Florida. Environ. Florida. Fla. Entomol. 75: 248-257. Entomol. 24: 1290-1296. Porter, S. D., and D. A. Savignano. 1990. Invasion of Jusino Atresino, R., and S. A. Phillips, Jr. 1994. Impact polygyne fire ants decimates native ants and dis- of red imported fire ants on the ant fauna of central rupts arthropod community. Ecology 71: 2095- Texas, pp. 259-268. In D. F. Williams [ed.], Exotic 2106. ants: biology, impact, and control of introduced Porter, S. D., B. Van Eimeren, and L. E. Gilbert. 1988. species. Westview, Boulder, CO. Invasion of red imported fire ants (Hymenoptera: Kauffeld, C. 1957. Snakesand snakehunting. Hanover Formicidae): microgeography of competitive re- House, Garden City, NY. placement. Ann. Entomol. Soc. Am. 81: 913-918. Killion, M. J., and W. E. Grant. 1993. Scaleeffects in Porter, S. D., A. P. Bhatkar, R. Mulder, S. B. Vmson,

AMERICANENTOMOLOGIST. Spring 2001 and D. J. Clair. 1991. Distribution and density of Aphidiidae), and the parasitoid Lysiphlebus polygyne fire ants (Hymenoptera: Formicidae) in testaceipes Cresson (Hymenoptera: Aphidiidae). Texas. J. Econ. Entomol. 84: 866-874. Ann. Entomol. Soc. Am. 84: 158-164. Price, A. H. 1990. Phrynosoma cornutum (Harlan) Vinson, S. B., J. L. Thompson, and H. B. Green. 1967. Texas horned lizard, pp. 469.1-469. Catalogue of Phagostimulants for the imported fire ant, Solenopsis American amphibians and reptiles. Society for Study saevissima val: richeen".J.lnsect Physiol. 13: 1729-1736. of Amphibians and Reptiles, Bethesda,MD. Whiting, M. J. 1994. Pseudemys texana (Texas river Reagan, T. E., G. Coburn, and S. D. Hensley. 1972. cooter). Nesting interference. Herpetol. Rev. 25: 25. Effects of mirex on the arthropod fauna of a Louisi- Williams, H. J., M. R. Strand, G. W. Elzen, S. B. Vmson, ana sugarcanefield. Environ. Entomol. 1: 588-591. and S. J. Merrirt. 1986. Nesting behavior, nest ar- Ricks, B. L., and S. B. Vinson. 1970. Feeding accept- chitecture, and use of Dufour's gland lipids in nest ability of certain insects and various water-soluble provisioning by Megachile integra and M. mendica compounds to two varieties of the imported fire mendica (Hymenoptera: Megachilidae). J. Kans. ant. J. Econ. Entomol. 63: 145-148. Entomol. Soc. 59: 588-597. Roe, R. A., II. 1973. A biological study of Solenopsis Wilmers, T. J., E. S. Wilmers, M. Miller, and P. Wells. invicta Buren, the red imported fire ant, in Arkan- 1996. Imported fire ants (Solenopsis invicta): a grow- sas with notes on related species.M.S. thesis, Uni- ing menace to sea turtle nests in Key West National versity of Arkansas. Wildlife Refuge, pp. 341-343. In J. A. Keinath, D. Schrader, E. 1999. There's no quick fix for fire ant E. Barnard, J. A. Musick, and B. A. Bell [eds.], Pro- problem. Los Angles Times. 2 December 1998, pp. ceedings of the 15th Annual Workshop on Sea Tuttle Al, A18. Biology and Conservation. U.S. Department of Com- Schwalbe, C.P. 1998. Imported fire ant quarantined merce, NOAA technical memorandum NMFS- areas. Federal Register 63: 36155-36156. SEFSC. Sikes,P. J., and K. A. Arnold. 1986. Red imported fire Wilson, E. 0., and W. L. Brown,Jr. 1958. Recent changes ant (Solenopsis invicta) predation on cliff swallow in the introduced population of the fire ant Solenopsis (Hirundo py"honota) nestlings in east-centralTexas. saevissima (Fr. Smith). Evolution 12: 211-218. Southwest. Nat. 31: 105-106. Wilson, N. L., and A. D. Oliver. 1969. Food habits of Smith, T. S., S. A. Smith, and D. J. Schmidly. 1990. the imported fire ant in pasture and pine forest ar- Impact of fire ant (Solenopsis invicta) density on eas in southeastern Louisiana. J. Econ. Entomol. northern pygmy mice (Baiomys taylori). Southwest. 62: 1268-1271. Nat. 35: 158-162. Wojcik, D. P. 1994. Impact of the red imported fire ant Sorensen,A. A., T. M. Busch, and S. B. Vinson. 1983. on native ant species in Florida, pp. 269-281. In D. F. Behavior of worker subcastes in the fire ant, Williams [ed.], Exotic ants: biology, impact, and con- Solenopsisinvicta, in responseto proteinaceousfood. trol of introduced species. Westview, Boulder, CO. Physiol. Entomol. 8: 83-92. Sterling, W. L. 1978. Fortuitous biological suppression Daniel P. Wojcik and Donald P. Jouvenaz are of the boll weevil by the red imported fire ant. retired research entomologists in the Imported Environ. Entomol. 7: 564-568. Fire Ant and Household Insects Researchunit at Summerlin,J. W.,A. C. F. Hung, and S.B. Vmson. 1977. the Center for Medical, Agricultural and Residuesin nontarget ants, speciessimplification and Veterinary Entomology, USDA-ARS, P.O. Box recovery of populations following aerial applications 14565, Gainesville,FL 32604 (dwojcik@gainesville. of mirex. Environ. Entomol. 6: 193-197. Summerlin, J. W., H. D. Petersen, and R. L. Harris. usda.ufl.edu). They have worked for over 30 years 1984a. Red imported fire ant (Hymenoptera: each on fire ants and their ecological effects and Formicidae): effects on the horn fly (Diptera: Mus- continue to study fire ants in retirement. RichardJ. cidae)and coprophagous scarabs.Environ. Entomol. Brenner ([email protected])is re- 13: 1405-1410. searchleader of the IFA &HI ResearchUnit. Cur- Summerlin,J.W., R. L. Harris, andH. D. Petersen.1984b. rently, he is involved in using spatially based risk Red imported fire ant (Hymenoptera: Formicidae): assessmentand mitigation of fire ants in relation frequency and intensity of invasion of fresh cattle to biocontrol agents and nontarget organisms. droppings. Environ. Entomol. 13: 1161-1163. Craig R. Allen is a wildlife biologist with the U.s. Thompson, L. C., D. B. Jones, F. N. Semevski,and S. Geological Survey,Biological ResourcesDivision, M. Semenov.1995. Fire ant economic impact: Ex- tending Arkansas' survey results over the South, pp. South Carolina Cooperative Fish and Wildlife- , 155-156. In S. B. Vinson and B. M. Drees [eds.], ResearchUnit, Clemson University, Clemson, SC Proceedingsof the 5th International Pest Ant Sym- 29634 ([email protected]).He is involved in : posia and the 1995 Imported Fire Ant Conference, numerous projects assessingthe effects of fire ants San Antonio, TX. on endangeredspecies. Elizabeth A. Forys is pro- VInson, S. B. 1994. Impact of the invasion of Solenopsis fessorof biology in the Natural SciencesCollegium invicta Buren on native food webs, pp. 240-258. In , Eckerd College, St. Petersburg, FL 33711 D. F. Williams [ed.], Exotic ants: biology, impact, ([email protected]).She was the lead scientistin and control of introduced species. Westview, the studies in the Florida Keys and continues her Boulder, CO. studies on invasive specieseffects on wildlife. R. Vinson, S. B. 1997. Invasion of the red imported fire Scott Lutz is professor in the Department of Wild- ant (Hymenoptera: Formicidae): Spread, biology, and impact. Am. Entomol. 43: 23-39. life Ecology, University of Wisconsin-Madison, Vinson, S. B., and T. A. Scarborough. 1991. Interac- Madison, WI 53706 ([email protected]).He tions between Solenopsis invicta (Hymenoptera: was instrumental in some initial studies of fire ant Formicidae), Rhopalosiphum maidis (Homoptera: effectson wildlife and continuesto work in this area.

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