Solenopsis Saevissima Research Articles

Systematics and Population Genetics of Fire Ants (Solenopsis saevissima Complex) from Argentina

Systematics and Population Genetics of Fire Ants (Solenopsis saevissima Complex) from Argentina

Two Different Decision-Making Systems in Recruitment To Food in Ant Societies

Few is known about decision-making inside a society of social organisms. Questions like: Do optimal decision-making systems exist?, and: Are there common solutions for decision-making in the animal kingdom?; are still unanswered. The social insects seem to be an appropriate model for this kind of study (DENEUBOURG, 1977), although no comprehensive work exists on the subject. Within the social insects the ants seem to be the most suitable for this purpose because: aall ants live in complex societies (WILsON, 1971); bmost ants use some kind of recruitment (AFFE, 1984); and cdecision-making is a fundamental ingredient of recruitment in ants (AFFE, 1980). Different food recruiting mechanisms are known for ants (WILSON, 1971; HOLLDOBLER, 1978; DUMPERT, 1978; JAFFE, 1984), but in most of them, only the behaviour of the recruiting ant has been described. For Solenopsis saevissima (WILSON, 1962) and for Atta cephalotes (JAFFE & HOWSE, 1979), inferences about how the behaviour of the individuals may account for collective phenomena have been made. For both species, the authors proposed a chemical mass recruitment system which has the following characteristics:

Karyotypes of Thirteen Ant Species from Uruguay (Hymenoptera, Formicidae)

SUMMARYThe karyotypes of thirteen species of Uruguayan ants belonging to three different subfamilies (Myrmicinae, Dolichoderinae and Formicinae) are reported. Among eight myrmicines studied, the chromosome numbers of four species of Pheidole (P. cornutula, P. fallax, P. spinninodis and P. strobeli) were all 2n = 20 (or n = 10). A count of 2n = 32 (or n=16) was obtained for Solenopsis saevissima, while 2n = 38 occurred in three leaf-cutter ants of the genus Acromyrmex [A. (Acromyrmex) ambiguus, A. (A.) hispidus and A. (Moellerius) heyeri]. The one dolichoderinae ant examined, Conomyrma pyramica, had 2n = 18 and three species of Camponotus, C. bonariensis, C. punctulatus and C. rufipes (Formicinae), showed a relatively high number 2n = 40 (or n=20) compared to that in C. mus (2n = 26).

Regional Variation in the Seasonal Activity of the Imported Fire Ant, Solenopsis saevissima richteri1

Studies were conducted over a one-year period at 6 locations throughout the range of the imported fire ant, Solenopsis saevissima richteri Forel, to determine regional variations in the seasonal activity of this pest. Threshold levels for various types of activity were found to be uniformly temperature-dependent in all parts of the range. Workers began to forage when soil temperatures exceeded 10°C. Some foraging occurred even in the winter months in the northern part of its range when the daily temperature exceeded this threshold for more than a few hours. Brood production in spring began when the weekly mean soil temperature (at 5 cm) rose above 10°C, worker and sexual pupae appeared at ca. 20°C, and the alates at 22.5°C. In Florida the period of favorable soil temperature for new colony-founding and growth (24°C) lasted ca. 198 days; in northern Mississippi it lasted 83 days. Similarly, the ants in Florida were found to consume twice as much food annually and to produce 1.5 times more brood than the ants in the northern part of the range.

The Red Imported Fire Ant, Solenopsis invicta;1 Distribution and Habitat in Mato Grosso, Brazil2

A 17-day trip was made through the States of Sao Paulo, Mato Grosso, Rondania Territory, Goias, and Minas Gerais, Brazil, to study the Solenopsis saevissima (Smith) complex. Special emphasis was on the distribution and ecology of Solenopsis invicta Buren. S. invicta was established in an area bordered by Caceres, Rondonopolis, Chapada, and Terenos in the State of Mato Grosso, and was also found at Porto Velho, Rondonia Territory. Active colonies were present only in moist or protected areas. This study reconfirmed a previous postulation that areas of Mato Grosso were a part of the homeland of S. invicta , the “red imported fire ant” of southeastern United States.

Novos inimigos das formigas lava-pé (complexo Solenopsis saevissima (Hymenoptera: Formicidae).

During the pst tvo years studies vete conducted in Mato Grosso and São Paulo to determine the insect natural enemies of fite ants ia the Solenopsis saevissima complex. Thus far these studies have yielded 6 species of Pseudacteon ( Phori-dae), a new parasitic Apodicrania (Phoridae), one new parasite wasp, Orasema (Eucharitidae) and a new temporary social parasire, Solenopsis (Formicidae).Methods of collecting vete as follows: (1) placing an inverted vial over enemy vhileflying above fite ant vorlrera or resting on soil surface; (2) inundatang nest contents slowly ia a talced bucket; and (3) opening nest to verify presence of small gunes (Salenopsis).Notes on the biology and bebavior of the parasitic species are given along with a discussion of parasite-host relationships.

Fire Ants Attacked by Phorid Flies

Four species of the genus Pseudacteon (Diptera:Phoridae) were observed attacking fire ants in the Solenopsis saevissima complex (Hymenoptera:Formicidae). In descending order of frequency noted, the phorids were Pseudacteon pradei Borgmeier, Pseudacteon wasmanni Schmitz, Pseudacteon tricuspis Borgmeier, and Pseudacteon nudicornis Borgmeier. Two or 3 of the species were commonly taken at the same Solenopsis nest. The frequency of phorid attack on disturbed fire ants nests was several times greater than on undisturbed nests.

Ploygyny in a Colony of the Fire Ant Solenopsis geminata1

Although the queens of some ant species have long been known to unite to found colonies (pleometrosis), only a few species have been observed to have multiple queens in a single well-established colony (polygyny). Brian (1965) and Sudd (1967) reviewed the works of several authors that reported finding multiple queens in well-established colonies of certain Lasius species. Gray (1971) reported finding multiple queens in colonies of Myrmecia dispar (Clark) and M. desortum Wheeler. Wilson (1971) reviewed some of the same reports mentioned by Brian and Sudd and cited other instances of the finding of multiple queens in a single colony. He stated that large colonies of Campanotus herculeanus (Latrielle) and C. ligniperda (Latrielle) often contain several queens. He further stated that J. C. Moser and M. S. Blum, respectively, in personal communications had reported the occasional finding of 2 queens in colonies of Atta texana Buckley and “Solenopsis saevissima.” The latter species is very closely related to S. geminata (F.), belonging to the same genus. Also Markin et al. (1972) found as many as 50 of the queens of the red imported fire ant, Solenopsis invicta Buren, clustered together under stones, cans, or other debris following nuptial flights and from 2 to 5 queens in common brood chambers with egg masses and small larvae. However, by the time the 1st workers appeared, only a single queen remained and in well-established colonies no more than one fertile queen was ever found.

Predation on the Lone Star Tick 1 by the Imported Fire Ant 2 , 3

In tests conducted at Baton Rouge and Pine Grove, Louisiana, various stages of the lone star tick, Amblyomma americanum (L.), were released in areas infested with the imported fire ant, Solenopsis saevissima richteri Forel, and in areas where mirex bait was applied to suppress ant populations. A significant ( P <0.01) greater survival of tick eggs and engorged tick larvae occurred in the mirex-treatcd area after 24, 48, and 72 hours of exposure to fire ant predation. About 75% of the ticks released in the mirextreated plot in August and September 1970 as nymphs were recovered as adults in March 1971. No ticks were recovered in the ant-infested plot. Engorged female ticks confined in hardware-cloth cages had a much higher survival rate in the mirex-treated plots.

Odonata in the Florida Soybean Agroecosystem

Thirty-five species of Odonata, including 4 families of Anisoptera and 3 families of Zygoptera, were observed in Florida soybean fields. Where possible, time of flight, flight pattern, feeding habits, and prey taken were recorded. Nine species appeared to be numerous enough and sufficiently selective in feeding habits to be capable of affecting prey populations. Three dragonfly species possibly may affect prey of economic importance. These were Erythemis simplicicollis (Say) which fed on Heliothis zea (Boddie), H. viriscens (Fabricius), and Pseudoplusia includens (Walker); Pachydiplax longipennis (Burmeister) which fed on alate imported fire ants, Solenopsis saevissima richteri Forel and Mexican bean beetle, Epilachna varivestis Mulsant; and Perithemis tenera seminole Calvert which fed on dolichopodid flies. Only 1 species of damselfly, Anomalagrion hastatum (Say) was consistently associated with soybean culture.

Confrontation Behavior Between Lasius neoniger (Hymenoptera: Formicidae) and the Imported Fire Ant 1 , 2

Confrontation behavior of the imported fire ant, Solenopsis saevissima richteri Forel, and Lasius neoniger Emery was studied in the laboratory and field. Workers of L. neoniger attacked those of S. saevissima richteri. Usually an antenna of the imported fire ant was seized and passed between the clypeus and mandibles of L. neoniger. The L. neoniger sprayed a secretion from the acidopore of the gaster into the imported fire ant's facial area; many imported fire ants were killed. Although imported fire ants had difficulty getting close enough to sting, the venom secreted from the sting was fatal to L. neoniger workers. A laboratory confrontation index showed that L. neoniger workers could destroy 2 to 3 imported fire ants for each one of its own killed. Eventually L. neoniger colonies were destroyed by the overwhelming number of workers in the imported fire ant colonies.

On the Eradication of Imported Fire Ants: A Theoretical Appraisal

In 1957 the United States Congress established a cooperative Federal-State program which had as its objective the control and containment of the imported fire ant, Solenopsis saevissima richteri Forel, within the limits of its distribution at that time. Long-lasting insecticides (heptachlor and dieldrin) were used in the early stages of the campaign, but the development of mirex bait (Lofgren et al. 1963, 1964; Stringer et al. 1964) and its adoption as the standard control in the early 1960's eliminated the need for these insecticides in the large-scale control program.

Changes in Nutrient Content during One Year in Workers of the Imported Fire Ant1,2

Analyses for total protein, lipids, glycogen, and glycerol were made on samples of major and minor workers of the imported fire ant, Solenopsis saevissima richteri Forel (Hymenoptera: Formicidae), which were collected over a period of one year. Protein content decreased during brood production and increased during periods when brood was not present in the mound. There was a buildup of lipid during the summer which appeared to be utilized during the cold months. Glycogen increased during the summer and may have been used for brood production when other nutrients were not abundant. Glycerol appeared to increase in response to aphid tending, decreasing in winter.

Inquilines and Other Arthropods Collected from Nests of the Imported Fire Ant, Solenopsis saevissima richteri1

Fifty-two species of arthropods were collected from nests of the imported fire ant, Solenopsis saevissima richteri Forel (Hymenoptera: Formicidae), between June 1968 and August 1969. Based on frequency of encounter, most collections were probably a result of chance occurrence of the arthropods. However, 3 species of insects, Myrmecaphodius sp. probably excavaticollis (Blanchard (Coleoptera: Scarabaeidae), Myrmecasaurus sp. (Coleoptera: Staphylinidae), and an undescribed species of Thysanura, and 1 unidentified species of mite (Acarina: Uropodidae) were frequently collected in ant nests, and apparently live in various types of association with this ant.

The Seasonal Life Cycle of the Imported Fire Ant, Solenopsis saevissima richteri1, on the Gulf Coast of Mississippi

During 1968, examinations of over 150 mounds of the imported fire ant, Solenopsis saevissima richteri Forel (Hymenoptera: Formicidae) were made in the vicinity of Gulfport, Mississippi. The ant was shown to have a yearly developmental cycle that started in early March with the beginning of egg laying and continued until November, when the disappearance of most of the brood indicated an end to the cycle. Alate forms were most abundant in early spring, reaching a peak of 9% of the colony biomass in June. Production of alate forms decreased steadily during the summer and ceased around September. Overwintering alates formed 1–2% of the colony biomass between November and May. Worker production began in March with peaks observed in May and October. During the developmental season, 19.6% of the total colony biomass was comprised of brood.

Multiple Fire Ant Stings

The imported fire ant, Solenopsis saevissima var richteri, first appeared near Mobile, Ala, around 1930, and is now found throughout the Southeastern United States. Solenamine, the active fraction of fire ant venom, is a potent necrotoxic agent. Imported fire ant stings produce characteristic pustular lesions which often are arranged in a circular pattern. Thousands of these lesions may be seen in alcoholics who inadvertently disturb a fire ant mound.

The chemistry of fire ant venom

Five alkaloids, three trans-2-methyl-6-alkylpiperidines, and two unsaturated analogues, have been identified in the venom of the red form of the fire ant, Solenopsis saevissima. The compounds are represented by the structural formulae I–V. Each has been prepared synthetically. These compounds, which appear to be the sole constituents of the venom, are believed unique among animal venoms.

Fur-Ag®: An Alternate Carrier for Soybean Oil-Mirex Bait for Control of the Imported Fire Ant13

Results of studies to develop toxic baits for control of the imported fire ant (IFA), Solenopsis saevissima richteri Forel, have been reported (Bartlett and Lofgren 1961; Lofgren et al. 1961, 1963, 1964; Stringer et al. 1964). It was found that a bait composed of once-refined soybean oil (the food material), mirex (the toxicant), and corncob grits (the carrier) was effective in reducing or eliminating infestations.

Relationship of the Imported Fire Ant to Nantucket Pine Tip Moth Infestations123

Field studies were conducted in southeastern Louisiana in 1966 and 1967 to determine the effect of imported fire ant, Solenopsis saevissima richteri Fore!, predation on larval and pupal populations of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock). Results indicate that predation by the imported fire ant reduced larval and pupal populations of the pine tip moth very little. Counts of both larvae and pupae indicated about equal populations in both heptachlor-treated and untreated plots from early June through October. Spider counts also suggest that spiders influence larval and pupal tip moth populations only slightly during the summer season.

Alkaloid from Fire Ant Venom: Identification and Synthesis

An alkaloid, trans-2-methyl-6-n-undecylpiperidine (solenopsin A), has been isolated from the venom of the fire ant Solenopsis saevissima. The structure has been confirmed by an unambiguous synthesis.