John C. Moser

Biological Responses of Atta texana to Its Alarm Pheromone and the Enantiomer of the Pheromone

S-(+)-4-Methyl-3-heptanone is the principal alarm pheromone of Atta texana. The dextrorotatory form of the ketone has also been identified from Atta cephalotes. Both enantiomers have been synthesized in high optical purity; Atta texana is more responsive to the (+) enantiomer than to the (-) form. These results implicate a chiral receptor system.

Alarm pheromones of the ant atta texana.

Abstract 4-Methyl-3-heptanone (0·59 μg/head) and 2-heptanone (0·14 μg/head) are the main volatile components of the mandibular glands of major workers. In the laboratory, worker ants detected and were attracted by 4-methyl-3-heptanone at a concentration of 5·7 × 10−13 g/cm3 (2·7 × 107 molecules/cm3). They were alarmed by a concentration of 5·7 × 10−12 g/cm3 (2·7 × 108 molecules/cm3). 2-Heptanone is less effective by a factor of 1000. In the field, low concentrations attract and alarm; high concentrations repel and alarm.

Use of sporothecae by phoretic Tarsonemus mites to transport ascospores of coniferous bluestain fungi

Certain female Tarsonemus mites, like their host bark beetles, carry a specific fungus upon which the mites feed, inside a special morphological, spore-carrying structure called a sporotheca. The sporotheca is similar to the mycangium described for bark beetles, but differs in that no gland cells are present and the fungal spores do not multiply in the structure. So far, the phenomenon has been observed only in North America and China where the phoretic hosts of the mites are Dendroctonus and Ips .

Isolation, identification, synthesis and biological activity of volatile compounds from the heads of Atta ants

Abstract S-(+)-4-methyl-3-heptanone has been identified as the principal alarm pheromone of Atta texana and Atta cephalotes . Both enantiomers of 4-methyl-3-heptanone have been synthesized and their biological activities have been compared on both species of ants. Comparison of the geometric averages of response ratios, at threshold concentration levels on A. texana , showed S-(+)-4-methyl-3-heptanone to be about 100 times more active than the (−) enantiomer. A similar analysis also showed no inhibition of the activity of S-(+)-4-methyl-3-heptanone by the (−) enantiomer. A less rigorous study on A. cephalotes showed S-(+)-4-methyl-3-heptanone to be about 210 times more active than R-(−)-4-methyl-3-heptanone. Both ant species produce 3-octanone, possible trace amounts of 3-octanol, and both diastereomers of 4-methyl-3-heptanol. A. texana also produces (+)-2-heptanol, 2-heptanone, and 3-heptanol. A. cephalotes contains trace amounts of 2-heptanone.

Ascospores hyperphoretic on mites associated with Ips typographus

Ten morphologically distinct types of ascospores were recognized from the bodies of 17 species of mites associated with adults of Ips typographus collected from pheromone traps in Sweden. The ascospores seemed to stick anywhere on the mites, with no special spore-carrying structures (sporothecae) evident. Most of the 739 mite individuals examined in this study transported one or more species of ascospore, sometimes in large numbers. One mite carried as many as six species. Ophiostoma polonicum , the most pathogenic of the blue-stain species, was noted on nine mite species, sometimes in large numbers.

Mating activities ofAtta texana (Hymenoptera, formicidæ)

SummaryAlate broods are reared without worker broods in lower cavities of nests in winter, and with worker broods in upper cavities of nests in spring. Winged adults appear in early April, but swarming does not occur until late May. Flights issue yearly from most large nests. The alate sex ratio is about 1∶1. Before swarming will occur, nest surfaces must be soaked with at least 7 mm of rain; flights continue as long as nests remain wet and temperatures exceed 16°.A circadian rhythm triggers swarming at about 3∶55 a.m., and most alates leave the nest surface within 2 minutes. Fertilized females contain from 69 to 186 million spermatozoa. Seminal vesicles of males contain 65 to 130 million spermatozoa.ZusammenfassungGeflügelte Nachkommenschaft wird im Winter in den unteren Hohlräumen des Nests ohne die Brut der Arbeiterinnen aufgezogen und im Frühling mit der letzteren zusammen in den oberen Hohlräumen des Nests. Geflügelte erwachsene Ameisen earschienen Anfang April, schwärmten aber erst Ende Mai. Flüge fanden jährlich von den meisten grossen Nestern aus statt. Bie den geflügelten Individuen war das Verhältnis der Geschlechter 1∶1. Vor dem Schwärmen war die Nestoberfläche mit mindestens 7 mm Niederschlag durchnässt worden; Flüge wurden fortgesetzt solange die Nester feucht waren und die Temperatur 16° C überschritt.Ein Tagesrhytmus löste das Schwärmen ungefähr um 3 Uhr 55 Minuten morgens aus, und die meisten geflügelten Ameisen verliessen die Nestoberfläche innerhalb von 2 Minuten. Befruchtete Weibchen enthielten zwischen 69 und 186 Millionen Spermatozoen; Samentasche der Männchen enthielten 65 bis 130 Millionen Samenzellen.Resumen (2)Durante el invierno, las creasas aladas son criadas en la ausencia de cresas trabajadoras en las cavidades inferiores de los nidos, pero durante la primavera, son criadas junto a creasas trabajadoras en las cavidades superiores de los nidos. Los adultos alados aparecen temprano en abril, pero los vuelos ocurren terde en mayo. Los sexos aparecen en proporció unitaria en los adultos alados. Los vuelos ocurren cuando las superficies de los nidos han sido humedecidas con 7 mm de agua y continúan ocurriendo mientras haya suficiente humedad y la temperature sobrepase 16° C.Los vuelos son iniciados por un ritmo diario y comienzan alrededor de las 3∶55 A.M. La mayor parte de los adultos alados emprende vuelo en un término de 2 minutos. Las hembras fecundadas contienen de 69 à 186 millones de espermatozoides; las vesículas seminales de los machos contienen de 65 a 130 millones.

Hyperphoretic Dispersal of a Pyxidiophora Anamorph

It has been suggested that Thaxteriola species and other minute, nonmycelial fungi associated with arthropods have phylogenetic relationships with the Laboulbeniales. However, direct development of the thallus of Thaxteriola from an ascospore of Pyxidiophora has now been discovered. Thaxteriola is specialized for dispersal by mites carried on pine bark beetles; other fungi dispersed by arthropods in this symbiotic assemblage rely primarily on arthropod specializations.

Transportation of phytopathogenic fungi by the bark beetle Ips sexdentatus boerner and associated mites

The bark beetle Ips sexdentatus carries several types of conidiospores and ascopores in the pronotal punctures located around the setae on the sides of the pronotum. For swarming beetles, some of the spores seem to be germinating.

Ascospore dispersal of Ceratocystiopsis ranaculosus, a mycangial fungus of the southern pine beetle

Ascospores of the heterothallic fungus Cer- atocystiopsis ranaculosus were found in sporothecae of three mite species of the genus Tarsonemus. These mites were phoretic on the coniferous bark beetles Den- droctonus frontalis, D. brevicomis, and Ips acuminatus. Ceratocystiopsis ranaculosus inhabits the mycangium of both Dendroctonus species as conidia in a budding yeast- like form. Ascospores are not known to occur in my- cangia of bark beetles, and the means of ascospore dispersal has not previously been reported. It is pos- tulated that ascospores transported by phoretic mites may be responsible for establishing sexually compat? ible colonies of the fungus in beetle galleries either by themselves or in combination with the mycangial fun? gus type.

Laboratory investigations of the trail-following responses of four species of leaf-cutting ants with notes on the specificity of a trail pheromone of Atta texana (Buckley)

SummaryInterspecific trail following activity of poison sac contents from four species of leaf-cutting ants was investigated. With only one exception, all the species tested followed trails made from each others poison sac contents. However when the ants were given a choice of following one of two separate trails, clear differences were shown in the poison sac contents of the three species tested.The responses of 24 species of ants and one species of termite to anAtta texana (Buckley) trail pheromone were tested.RésuméNous avons étudié comment quatre espèces de FourmisAtta suivent mutuellement les pistes tracées avec le contenu de leur sac à venin. Toutes les espèces étudiées ont suivi les pistes des autres à une seule exception. Cependant, lorsque nous avons donné aux Fourmis le choix entre deux pistes distinctes, nous avons montré quil y avait des différences dans le contenu du sac à venin de trois espèces.Nous avons étudié les réponses de 24 espèces de Fourmis et dune espèce de Termite à une phéromone de piste deAtta texana (Buckley).