Sex Pheromone of Queens of the Slave-Making Ant, Polyergus breviceps (original) (raw)
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Sex Attractant Pheromone of the Japanese Slave-Making Ant, Polyergus samurai
Journal of Chemical Ecology, 2020
The objective of our project was to identify the sex attractant pheromone of queens of the slave-making ant Polyergus samurai, which was characterized as a blend of methyl 6-methylsalicylate and methyl 3-ethyl-4-methylpentanoate. Both compounds were identified in volatiles collected from squashed heads of queens, and in field trials, a blend of the two compounds was highly attractive to males. In contrast, males were not attracted to a blend of methyl 6-methylsalicylate with 3-ethyl-4-methylpentanol. Thus, the pheromone blend of this species is analogous to that of species in the Polyergus lucidus complex from eastern North America, rather than that of the Polyergus breviceps complex from western North America and the European species P. rufescens. These results are discussed in the context of speciation within the genus.
Queen Sex Pheromone of the Slave-making Ant, Polyergus breviceps
Journal of Chemical Ecology, 2007
Workers of the slave-making ant, Polyergus breviceps, raid nests of Formica ants and return with Formica pupae that mature into worker ants in the slave-makers' colony. These Formica workers then tend the Polyergus brood, workers, and reproductives. During raids in the mating season, winged virgin Polyergus queens accompany the workers in the raiding columns. During the raid, the virgin queens release a pheromone that attracts males that quickly mate with the queens. We report the identification, synthesis, and bioassay of the sex attractant pheromone of the queens as an approximately 1:6 ratio of (R)-3-ethyl-4methylpentan-1-ol and methyl 6-methylsalicylate. The ants produce exclusively the (R)enantiomer of the alcohol, and the (S)-enantiomer has no biological activity, neither inhibiting nor increasing attraction to blends of methyl 6-methylsalicylate with the (R)-enantiomer.
Insectes Sociaux, 2008
The aim of the research reported here was to determine whether 3-ethyl-4-methylpentanol, a minor but crucial component of the sex pheromone of the North American slave-making ant species Polyergus breviceps, was also a component of the sex pheromone of the European congener Polyergus rufescens. Thus, the contents of mandibular glands of P. rufescens virgin queen were extracted and analysed. The main component of the extracts was methyl 6-methylsalicylate and 3-ethyl-4methylpentanol was identified as one of several minor components. Further analyses showed that the insects produce mainly the (R)-enantiomer of the alcohol. Males responses to various blends of methyl 6-methylsalicylate with the racemate or the pure enantiomers of 3-ethyl-4methylpentanol were tested in field behavioural bioassays. The data showed that blends of methyl 6methylsalicylate and 3-ethyl-4-methylpentanol were strongly synergistic, with the most active ratios being biased toward the first component. The addition of other minor components to the binary blend neither increased nor decreased responses by males. Only the (R)-enantiomer of the alcohol was biologically active; its antipode did not inhibit attraction. The results are discussed in terms of the evolution of signals, and are compared with the results previously obtained for the allopatric species Polyergus breviceps.
Multiple glandular origins of queen pheromones in the fire ant Solenopsis invicta
Journal of Insect Physiology, 2000
The poison sac of the fire ant Solenopsis invicta is the only identified glandular source of pheromones produced by a functional ant queen. This structure, which contains the poison gland, has previously been shown to be the source of a releaser pheromone that mediates queen recognition and tending by workers. The poison sac has also been demonstrated to be the source of a primer pheromone that inhibits winged, virgin queens from shedding their wings (dealating) and developing their ovaries. To determine if the poison sac was the only source of these pheromones, we excised the poison sac from queens and observed whether operated queens retained their pheromonal effects. In a first experiment, the poison sac was removed from functional (egg-laying) queens which were then paired with unoperated nestmate queens in small colonies. Counts of the workers surrounding each queen two weeks after the operation showed that queens without poison sac were as effective as their unoperated nestmates in attracting worker retinues. In a second experiment, we removed the poison sacs of virgin queens which had not yet begun laying eggs and thus had not begun producing queen pheromone. After allowing them to develop their ovaries, these individuals produced amounts of queen recognition pheromone comparable to those secreted by unoperated or sham operated virgin queens as determined by bioassay. Testing the head, thorax and abdomens of functional queens separately revealed that the head was the most attractive region in relation to its relative surface area. Bioassays of extracts of two cephalic glands—the mandibular gland and postpharyngeal gland— showed that the postpharyngeal gland is a second source of the queen recognition pheromone. Finally, we found that virgin queens whose poison sacs were removed before they began producing queen pheromone initiated production of a primer pheromone that inhibits winged virgin queens from dealating, indicating that this pheromonal effect also has an additional but as yet undetermined source. These results parallel those on the honey bee in which several of the pheromonal effects of functional queens appear to have multiple glandular sources.
Studies on the mode of action of a queen primer pheromone of the fire ant Solenopsis invicta
Journal of Insect Physiology, 1994
Studies were conducted on the physiological mode of action and mode of perception of a queen pheromone that inhibits dealation (wing-shedding) and ovary development in virgin queens of the fire ant Solenopsis invicta. Winged virgin queens were removed from the pheromonal signal (queen) to compare the response time for dealation, a behavioral response, and ovary development, a physiological response. Dealation was always accompanied by some degree of ovary development, whereas some individuals exhibited slightly developed ovaries before dealation occurred, suggesting that ovary development precedes dealation by several hours to a day. The response time of virgin queens following extinction of the pheromonal signal was highly variable and was related to colony source and body weight. Individuals from monogyne (single functional queen) colonies were more responsive than those from polygyne (multiple functional queens) colonies, a result consistent with the high cumulative levels of queen pheromone in the latter colonies. Virgin queens treated topically with the juvenile hormone (JH) analogue, methoprene, dealated and developed their ovaries in the presence of the pheromone (queen), suggesting that the pheromonal mode of action involves the suppression of JH titers. To obtain more precise information on the physiological processes underlying the inhibition of ovary development, vitellogenin titers were determined for virgin queens and functional (egg-laying) queens. Despite having undeveloped ovaries, virgin queens had vitellogenin titers that were as elevated as those of functional queens. This suggests that the effect of the low JH titers resulting from the primer pheromone is on the uptake of vitellogenin by the oocytes rather than on vitellogenin synthesis. The possible mode of perception of the inhibitory pheromone was also investigated. Virgin queens whose antennae had been removed dealated in the presence of the queen, suggesting that the pheromone acts by stimulating sensory cells in the antennae. The results are incorporated into a general model for the mode of action of the queen primer pheromone.
Insect chemical communication: Pheromones and exocrine glands of ants
Chemoecology, 1993
Chemical communication plays a very important role in the lives of many social insects. Several different types of pheromones (species-specific chemical messengers) of ants have been described, particularly those involved in recruitment, recognition, territorial and alarm behaviours. Properties of pheromones include activity in minute quantities (thus requiring sensitive methods for chemical analysis) and specificity (which can have chemotaxonomic uses). Ants produce pheromones in various exocrine glands, such as the Dufour, poison, pygidial and mandibular glands. A wide range of substances have been identified from these glands. Key words, pheromones-exocrine glands-behaviour-trail pheromone-Dufour gland-poison glandpygidial gland-chemotaxonomy-Hymenoptera-Formicidae Formicidae: the variety of ants Ants are among the most abundant living organisms. For example, Tobin et al. (see May 1989) found that ants represented 70% of all arthropod individuals, and about 50% of the animal biomass by dry weight, in the canopy fauna of an area of Amazonian rainforest. There are about 10,000 known species of ants. They form one family, the Formicidae, which is placed within the aculeate Hymenoptera along with bees and wasps. These species are classified within 297 genera in ten or eleven subfamilies (Table 1) (Baroni Urbani 1989; H611dobler & Wilson 1990). Ants are eusocial (literally, truly social) insects, that is, their colonies have the following three traits: cooperative brood care, overlapping adult generations, and more or less non-reproductive workers (Sudd & Franks 1987). The organisation of these intricate societies requires a highly developed communication system, and much of the complex social behaviour of ants is mediated by pheromones (Wilson 1971). Chemical communication Communication can be defined as a process by which information is exchanged between organisms. It may Range Medium Short Long Long Rate of change of signal Fast Fast Fast Slow Ability to circumvent obstacles Poor Poor Good Good Locatability High High Medium Variable Energetic cost Low Low High Low central nervous system. Releaser pheromones are usually categorised by the type of behaviour they evoke (Shorey 1973). The following seven classes are the main classes of insect releaser pheromones that have been described, most of which have examples among ants.
Italian Journal of Zoology, 2003
Female-calling syndrome' is the reproductive strategy adopted by the European slave-making ant Polyergus rufescens, where a winged female disperses a short distance from the nest, ascends to an elevated position (at the top of a blade of grass) and is joined shortly thereafter by conspecific males. This suggests the probable use of very effective sexual calling pheromones by females. Here, the role of the mandibular glands of winged females is demonstrated to be a source of sexual pheromones. The secretion of these glands (among the structures tested: the mandibular, Dufour, poison and pygidial glands and the head without mandibular glands) appears to have a strong attractive effect on males and also elicits male copulatory behaviour.