C. S. Lofgren

The queen recognition pheromone of solenopsis invicta, preparation of (E-6-(1-pentenyl)-2H-pyran-2-one.

The title compound, I, prepared in five steps via four known α-pyrones, is responsible, in part, for “queen recognition” by red imported fire ant workers. IR, NMR and MS data are presented.

Suppression and elimination of an island population of Culex pipiens quinquefasciatus with sterile males.

The release of 8,400 to 18,000 males per day of Culex pipiens quinquefasciatus Say which had been exposed to a sterilizing agent (thiotepa), suppressed and eliminated an indigenous population of this mosquito on an island off the coast of Florida in a 10-week period. Sterile males were effective in seeking out and mating with females on the island.

Synthesis and stereochemistry of tetrahydro-3, 5-dimethyl-6-(1)methylbutyl)-2H-pyran-2-one, a component of the queen recognition pheromone of solenopsis invicta.

Abstract One of the diastereomers of the title compound, I , isolated from imported fire ant queens, has been prepared and named invictolide . It is responsible, in part, for “queen recognition” by workers of the species.

Filtration of microparticles from liquids ingested by the red imported fire antSolenopsis invicta Buren

SummaryThe imported fire ant,Solenopsis invicta, has a highly efficient mechanism for filtering particles from food material. Latex microspheres as small as 0.88 μm were filtered and concentrated in the infrabuccal pocket. The compacted mass was then ejected as a pellet. The maximum size latex spheres swallowed by larvæ were 45.8 μm, which approximately corresponds to the diameter of the larval esophagus. The efficient filtration of particles offers little hope for the success of controlled release insecticide formulations that require ingestion of solid particles.ZusammenfassungDie importierte Fenerameise hat einen besonders wirksamen Mechanismus Fremdpartikelchen die in der Nahrung anwesend sind zu filtrieren. Latex Partikelchen von 0.88 μm Durchmesser wurden im infrabukalen Beutel filtriert und eingeengt. Die kompakte Masse wurde nachher als Kügelchen ausgestossen. Die von den Larven verschluckten Latex Kügelchen hatten einen Durchmesser, der eine Länge von 45.8 μm erreichen Konnte und dem Durchmesser der Speiseröhre der Larven entsprach. Die wirksame Filtrierung der Partikelchen bietet wenig Hoffnung auf Erfolg das Durchlassen der Kontrollierten Insektenvertilgungsmittel zu gestatten, wenn sie in harter Form verabreicht werden müssen.

Hydrocarbon components of the trail pheromone of the red imported fire ant, Solenopsis Invicta

Abstract Terpenoid trail pheromone components were isolated from whole worker extracts of the red imported fire ant, and identified as Z,E and E,E -α-farnesene, and the previously unreported homofarnesenes Z,Z and Z,E -3,4,7,11-tetramethy1-1,3,6,10-dodecatetraene.

Biochemical changes in the crop, oesophagus and postpharyngeal gland of colony-founding red imported fire ant queens (Solenopsis invicta)

Abstract Chemical analysis of hydrocarbons, triacylglycerols and free fatty acids present in hexane extracts of the crop, oesophagus and postpharyngeal gland of colony-founding queens of Solenopsis invicta Buren illustrates that the oesophagus enlarges into a thoracic crop concomitant with wing muscle histolysis. The flow of material goes from the crop to the oesophagus, but not to the postpharyngeal gland. In the crop and oesophagus triacylglycerols and the dominant chemical class, whereas the postpharyngeal gland contains primarily hydrocarbons. The pattern of postpharyngeal gland hydrocarbons changes between the time of insemination and 25 days after mating.

SPECIFICITY OF THE RED IMPORTED FIRE ANT (HYMENOPTERA: FORMICIDAE) PHAGOSTIMULANT RESPONSE TO CARBOHYDRATES

The red imported fire ant, Solenopsis invicta Buren, is considered an oil-loving feeder, however, carbohydrates are essential ingredients in the diet of the fire ant also. Comprehensive screening of mono-, di-, and tri-saccharides demonstrated that glucose, fructose, fucose, sucrose, maltose, turanose and raffinose were significant phagostimulants for fire ant workers. It was also found that while D-glucose and L-fucose, the naturally occurring isomers, were active, the opposite diastereomers were not. Any structural modification of the glucose molecule resulted in loss of activity. None of the sugar alcohols evaluated were active. The fire ant is an agricultural pest and the many reports of fire ant damage to food crops may be linked to their need for dietary carbohydrates. A knowledge of carbohydrate phagostimulants may help to understand specificity of fire ant /plant interactions.

Scientific Notes: First Report of a Parasitic Fly (Diptera: Phoridae) from a Red Imported Fire Ant (Solenopsis Invicta) Alate Female (Hymenoptera: Formicidae)

A number of phorid flies are known to parasitize various life stages of bees and wasps, including reproductives (Kistner 1982). Several genera of phorids are known or assumed to be parasitic on worker ants but not on reproductives (Borgmeier 1963; Borgmeier and Prado 1975). Williams (1980) summarized the known data on phorids attacking and parasitizing fire ants sens. str., Solenopsis (Solenopsis) spp., in South America. To date, only one species is definitely known to parasitize fire ant workers, although other species are assumed to be parasitic on fire ants (Williams 1980). None of these species are present in the United States (Borgmeier 1963). Fire ant colonies collected as part of our continuing survey for biological control agents of fire ants were processed by the methods given in Jouvenaz et al. (in press). One colony of Solenopsis invicta Buren, collected 5-Feb-85 on the road shoulder of BR-070, km 616, ca. 1/2 way between Caceres and Cuiaba, Mato Grosso, Brasil, in disturbed cerrado (arid tropical savanna), was found to contain an unidentified nematode (Jouvenaz et al. in press). During studies of the nematode, 200 adult workers, 200 worker pupae, 200 adult males, and 65 alate females (all that were present in the collection) were dissected, yielding one puparium of a phorid fly (identified by D. H. Habeck, Dept. Entomology and Nematology, University of Florida, Gainesville, FL) from one alate female (virgin queen). The first two body segments of the puparium were darkened and heavily sclerotized. Two large conspicuous horn-like structures were noted on the prothoracic segment, probably the prothoracic spiracles. The remainder of the puparium was white and unmelanized. No gross morphological alterations were noticed in the alate ant before dissection. After several months preservation in 70% ethanol, the unmelanized portion of the puparium cleared, revealing the partially developed pupa inside. The pupa had developed to the point of eye facet coloration but no other parts were melanized. Since fire ants are not routinely dissected as part of our survey in Brazil, a special effort was made to collect alate females from fire ant nests on a subsequent trip (February to March 1986). Alate females were found in 93 colonies. These were preserved in alcohol and dissected in the United States. Up to 20 alate females were dissected from each colony (total of 1,561). No fly puparia were found although an unidentified microsporidian disease and nematodes were found. This is the first report of a phorid fly parasitizing alate female ants of any species. This find raises the possibility that a species of phorid exists that may be good biological control agents for queens and alate females of fire ants, not just workers. The success of a biological control program for fire ants using parasitoids which affect only worker ants would not seem to hold much promise, because of the large numbers of workers in fire ant colonies (Markin et al. 1973). The possibility exists that this is an instance of mistaken parasitism by the fly. During mating flights, activity on the surface of fire ant mounds becomes very hectic and a phorid could attack an alate by mistake. All reported cases of attack on worker ants describe the ant as stunned (Williams 1980; Kistner 1982). An alate female which

CONTROL OF SOLENOPSIS INVICTA (HYMENOPTERA:FORMICIDAE) WITH TEFLUBENZURON

Teflubenzuron baits were active against laboratory colonies of the red imported fire ant, Solenopsis invicta Buren. Worker brood production ceased soon after treatment and by four weeks posttreatment, most colonies were devoid of brood. Worker ants did not exhibit any direct effects from treatment with teflubenzuron. As is typical with most insect growth regulators, colony mortality was slow and dependent on old-age attrition of the worker ants. A few (<25) female alates were produced in one of the laboratory colonies at 12 weeks posttreatment. The teflubenzuron baits reduced field colonies of S. invicta by 75-79% within 6 weeks after treatment, 83-86% within 13 weeks, and 77-91% within 17 weeks. At 17 weeks posttreatment, the presence of worker brood in the plots treated with the lower rates, 0.1125% and 0.0225%, gave evidence of recovery of some colonies. However, the results of the field tests indicate that teflubenzuron has excellent potential for control of field populations of S. invicta.

The sterile-male technique for control of mosquitoes : a field cage study with Anopheles quadrimaculatus.

The use of sterile males to control a cage population of a laboratory strain of Anopheles quadrimaculatus was not successful, even though 80 to 90% of the females laid sterile egg clutches. At the ratio of sterile males to normal males being used, complete sterility should have been quickly achieved. Subsequent studies of the survival and sexual vigor of these sterile males indicated that only a small number, about 5%, of the released males were actually competing with normal males for the uninseminated females. Thus, until a more hardy and sexually vigorous male A. quadrimaculatus can be reared in the laboratory, the use of the sterile-male technique to control this insect seems impractical.