Volatile components from the mandibular glands of the turtle ants, Cephalotes alfaroi and Cephalotes cristatus

GC–MS analysis of whole head extracts from the turtle ants, Cephalotes alfaroi and Cephalotes cristatus, showed that 4-heptanone and 4-heptanol were the major volatile components in the mandibular glands. 4-Heptanone and 4-heptanol have rarely been identified in mandibular gland secretions from other ant genera. Thus, these compounds may be chemotaxonomic markers for the genus Cephalotes, since they have been identified in the mandibular glands from all members of this genus that have been investigated to date. Minor components identified in the whole head extracts of these ants were 3-methyl-1-butanol, 3-heptanone, 3-hexanol, 2- and 3-methylbutanoic acids, 2-methyl-4-heptanone, 2-phenylethanol and phenol. To our knowledge, this is the first time that 2-methyl-4-heptanone and phenol have been reported in the mandibular gland secretion from any Formicid.     

Comparative study of the mandibular gland secretion of four species of Myrmica ants

The mandibular glands of the two species of ant, Myrmica ruginodis and Myrmica sabuleti contain a similar mixture of compounds, but the proportions are different. M. sabuleti produces ethanol, propanone, methylpropanal, 3-hexanone, 3-hexanol, 3-heptanone, 3-heptanol, 3-octanone, 3-octanol, 6-methyl-3-octanone, 6-methyl-3-octanol and 3-decanone. With the exception of 3-decanone these compounds were also found in M. ruginodis. These compounds were also found in M. rubra and M. scabrinodis.In both species now studied, the mandibular gland contents attract the workers and cause a large increase in their linear speed. In M. sabuleti these behavioural activities are due to 3-octanone and 3-octanol: the attraction of these two compounds in a synthetic mixture is exactly like that of an isolated mandibular gland; the compounds act in synergy to cause an increase in the ants' linear speed. Workers of M. ruginodis specifically respond to a mixture of ethanol, 3-octanone and 3-octanol: the alcohol only moderates the ethological action of the ketone, which is a true attractant and causes a very large increase in the ants' velocity; ethanol also attracts workers, acting in this respect in synergy with 3-octanone.These chemical and behavioural results are combined with those previously reported (Cammaerts-Tricot, 1973; Morganet al., 1978) to explain the responses of M. rubra, M. ruginodis, M. sabuleti and M. scabrinodis workers to isolated mandibular glands from each of these four species.     

Phéromones agrégeant les ouvrières de Myrmica rubra

The workers of Myrmica rubra aggregate around a source of one of their secretions, which can be called ‘alarm pheromone’, and also around workers of Lasius flavus. The mechanism of these aggregations differ.Both L. flavus workers and a solution in liquid paraffin of 3-octanol, one of the mandibular gland compounds, act as an arrestant for the workers of M. rubra. Both Dufour's gland secretion and a source of 3-octanone, the major compound of the mandibular gland secretion, are true attractants.The poison gland secretion, a mixture of 3-octanone and 3-octanol in liquid paraffin and a solution in liquid paraffin of 3-nonanone, a minor mandibular gland compound, all induce klinokinesis. The secretion of the mandibular glands and the secretion of the venom apparatus both cause positive klinokinesis and taxis. These locomotory reactions increase the probability that an object, marked by nest mates with these secretions, will be detected by several workers.When presented alone, 3-octanone is the only attractive compound in the mandibular gland secretion. However, a mixture of 3-octanone and 3-octanol (15 per cent of 3-octanol in the vapour phase) is detected more easily by the ants. The diffusion coefficients of the two compounds are different, and a mixture of these substances creates not only a quantitative but also a qualitative odour gradient. This may explain the synergy of the mixture.     

A comparison of mandibular gland volatiles from ants of the bull horn acacia,Acacia collinsii

GC–MS analyses of dichloromethane extracts of the mandibular glands from three obligate symbiotic Psuedomyrmex ant species of Acacia collinsii from Costa Rica: Pseudomyrmex flavicornis (synonym Pseudomyrmex belti), Psuedomyrmex spinicola, and Psuedomyrmex nigrocincta, showed distinct differences in the 16 ketones, 15 alcohols, 2 aldehydes and 2 carboxylic acids that were identified. Different compounds were the major component from each species: P. flavicornis, 3-octanone; P. spinicola, 4-methyl-3-heptanone; and P. nigrocincta, 3-methyl-2-hexanol. The secretion of P. flavicornis contained 10 compounds not found in the other species, including the two terpene alcohols, citronellol and geraniol. The secretions of P. spinicola and P. nigrocincta had 12 compounds in common, that were not found in P. flavicornis' secretion. The similarity of the mandibular gland secretion of P. spinicola and P. nigrocincta may indicate that they are more closely related to each other than either is to P. flavicornis. The components from the mandibular gland of Crematogaster rochai, another ant associated with this acacia, are 2- and 3-methylbutanoic acid, 3-octanone, 3-octanol, 6-methyl-3-octanol and 3-nonanone.     

Primer effect of queen pheromone on juvenile hormone biosynthesis in adult worker honey bees

Juvenile hormone synthesis in adult worker honey bees was measured by an in vitro corpora allata bioassay. Adult queenless workers exhibit higher rates of juvenile hormone biosynthesis than queenright workers. Hormone synthesis is not correlated with the volume of the glands. Extract of queen mandibular glands, applied to a dummy, reduces juvenile hormone biosynthesis in caged queenless workers to the level of queenright workers. The same result was obtained with synthetic (E)-9-oxo-2-decenoic acid, the principal component of the queen mandibular gland secretion. This pheromonal primer effect may function as a key regulating element in maintaining eusocial colony homeostasis. The presence of brood does not affect the hormone production of the corpora allata.Abbreviations BSA bovine serum albumin - CA Corpora allata - JH juvenile hormone - 9-ODA (E)-9-oxo-2-decnoic acid     

Effect of gland extracts on digging and residing preferences of red imported fire ant workers (Hymenoptera: Formicidae)

There is evidence that ant‐derived chemical stimuli are involved in regulating the digging behavior in Solenopsis invicta Buren. However, the source gland(s) and chemistry of such stimuli have never been revealed. In this study, extracts of mandibular, Dufour's, postpharyngeal, and poison glands were evaluated for their effect on ant digging and residing preferences of S. invicta workers from three colonies. In the intracolonial bioassays, workers showed significant digging preferences to mandibular gland extracts in 2 of 3 colonies and significant residing preferences in 1 of 3 colonies; significant digging preferences to Dufour's gland extracts in 1 of 3 colonies and significant residing preferences in 2 of 3 colonies. No digging and residing preferences were found for postpharyngeal and poison gland extracts. In intercolonial bioassays, significant digging and residing preferences were found for mandibular gland extracts in 3 of 6 colony combinations. Significant digging preferences to Dufour's gland extracts were found in 4 of 6 colony combinations and significant residing preferences in all 6 colony combinations. For postpharyngeal gland extracts, significant digging preferences were found only in 1 of 6 colonial combinations and no significant residing preferences were found. For poison gland extracts, no significant digging preferences were found; significant residing preferences were found in 1 of 6 colony combinations. However, a significant residing deterrence (negative residing preference index) was found for 2 of 6 colony combinations. Statistical analyses using data pooled from all colonies showed that mandibular and Dufour's gland extracts caused significant digging and residing preferences in both intracolonial and intercolonial bioassays but not postpharyngeal and poison gland extracts. By analyzing the data pooled from the same three colonies used for gland extract bioassays, it was found that, in no cases, workers showed significant digging and residing preferences to 2‐ethyl‐3,6‐dimethylpyrazine, an alarm pheromone component from mandibular gland.     

Response of workers of Atta sexdens rubropilosa (Hymenoptera: Formicidae) to mandibular gland compounds of virgin males and females

Abstract.  The secretion from the mandibular glands of males of the leaf-cutting ant Atta sexdens rubropilosa is responsible for the reaction of workers outside the nest at the time of sexual swarming. Workers respond with excitability and aggression when presented with the natural mixture of 4-methyl-3-heptanol and 4-methyl-3-heptanone, which is contained in the secretion of the male mandibular glands. Workers respond quickly to fractional amounts of one male equivalent. 4-Methyl-3-heptanone, from the virgin female mandibular glands causes much less response in workers, whereas an equimolar mixture of male and female pheromones gives a still less clear response. The male pheromone plays the most important part in the communication of workers outside the nest at this time.     

Chemical ecology of the meat ant,Iridomyrmex purpureus sens. strict.

Twelve volatile constituents have now been characterized from the common meat ant, Iridomyrmex purpureus sens. strict. 2,5-Dimethyl-3-ethyl-, 2,5-dimethyl-3-propyl- and 2,5-dimethyl-3-butyl-pyrazine were mandibular gland constituents, and in total represented < 1 ng/gland. The major constituents were confirmed as the known 6-methylhept-5-ene-2-one and the iridodials. The oxygenated compounds: 1,3,3-trimethyl-2,7-dioxabicyclo[2,2,1]heptane, not previously reported from an insect source, together with 2-acetyl-3-methylcyclopentene and 6-methylhept-5-ene-2-ol were minor products. Minor iridoids were 2-(3-methylcyclopentyl)propional, a dihydroneptalactone and an iridolactone, plus actinidine. The oxygenated volatiles and iridoids were isolated both from extracts of whole insects, and bodies of I. purpureus workers.The same chemical pattern was repeated in samples of I. purpureus sens. strict., collected over a wide area of south-eastern Australia. The several series of pyrazines, iridoids, carbonyl compounds and associated volatiles, together with the previously described hydrocarbons, serve to distinguish I. purpureus sens. strict. chemically.     

Selective preying of the sphecid wasp Trachypus boharti on the meliponine bee Scaptotrigona postica: potential involvement of caste‐specific cuticular hydrocarbons

The specialist digger wasp Trachypus boharti Rubio‐Espina preys exclusively on males of the stingless bee Scaptotrigona postica Latreille 1807, although the hunting attacks involve both male and worker bees of S. postica and members of its own species. To understand the mechanism of prey selection, the cuticular hydrocarbon patterns of workers and males of S. postica are analyzed in detail, and the mandibular secretion of males is examined. The cuticular profiles of males and workers are distinctively different. The major group of cuticular compounds, heptacosene isomers, is twice as abundant in workers as in males. There is no clear distinction between worker and male mandibular secretions. Such a distinct and straightforward caste‐specific difference in cuticular hydrocarbons could function as a recognition cue by which T. boharti distinguishes between workers and males of S. postica.     

Mandibular gland secretions of workers of Myrmica rugulosa and M.schencki: comparison with four other Myrmica species

ABSTRACT. The mandibular glands of the two species of ant, Myrmica schencki Em. and Myrmica rugulosa Nyl., contain mixtures of similar compounds, but in different proportions. M.rugulosa produces 3-pentanol, 3-hexanone, 3-hexanol, 3-heptanone, 3-heptanol, 3-octanone (by far the most abundant component), 3-octanol, 3-nonanol, 3-decanone and 6-methyl-3-octanone, in addition to small amounts of ethanal, acetone and methylpropanal. M.schencki produces most of these (though much less 3-octanone and much more 3-octanol), but also produces significant amounts of 3-nonanol, 3-decanol and 6-methyl-3-octanol, while producing no detectable 3-pentanol or 3-hexanone. The mandibular gland secretions of these two species attract the workers, increase their linear speed, and reduce their sinuosity of movement. In M.schencki these behavioural activities are caused by 3-octanol and 3-octanone, the effect of a synthetic mixture of the two being exactly like that of an isolated mandibular gland; the two compounds act together to cause attraction and increase linear speed, and in synergy to reduce the workers' sinuosity of movement. In M.rugulosa , 3-octanol, 3-octanone and 6-methyl-3-octanone are the major active constituents. 3-Octanone attracts the workers, its effect being enhanced by 3-octanol; it also increases the ants' linear speed, this effect being moderated slightly by the 3-octanol. Presented together these two substances act synergistically to decrease the workers' sinuosity of movement, and reproduce exactly the overall behavioural activity of an isolated mandibular gland. The chemical and behavioural results are combined with those previously reported to explain the responses of M.rubra, M.ruginodis, M.rugulosa, M.sabuleti, M.schencki and M.scabrinodis workers to isolated mandibular glands of these species.     

Alarm pheromones of the Attini: Their phylogenetic significance

The volatile components present in the mandibular glands of a number of species of the attine genera Cyphomyrmex (1 species), Trachymyrmex (3 species), and Acromyrmex (2 species) were investigated and compared with those present in Atta. The extracts were found to consist of mixtures of a number of compounds. All but one of these mixtures contained some or all of the following compounds: 3-octanone, 4-methyl-3-heptanone, 3-octanol, and 4-methyl-3-heptanol. The behavioural responses of Trachymyrmex and Cyphomyrmex workers to these compounds were tested. A common chemical heritage based on 3-ketones and 3-alcohols appeared to exist among the genera studied. The chemical data were compared with an accepted phylogeny of these genera to see whether it supported the phylogeny.     

The mandibular gland secretion of the ant, Myrmica scabrinodis

ABSTRACT. The volatile secretion of the mandibular gland of the common elbowed red ant, Myrmica scabrinodis Nyl., is shown to consist of ethanal, ethanol, acetone, 3-hexanone, 3-hexanol, 3-heptanone, 3-heptanol, 3-octanone, 3-octanol, 6-methyl-3-octanone, 6-methyl-3-octanol, 3-nonanone, 3-nonanol, 3-decanone and 3-undecanone. The electroantennographic response to the major components was recorded and compared with some related compounds. Behavioural tests were carried out on the major constituents, showing that 3-octanol is an attractant for workers, that 3-octanone increases the effect of 3-octanol, and 3-nonanone augments the linear speed of the ants.     

Synthesis and PGE2 production inhibition of 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives

3,4-Diphenyl-substituted 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives were synthesized and evaluated for the inhibitory activities on LPS-induced PGE₂ production in RAW 264.7 macrophage cells. Both 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione rings as main scaffolds were easily obtained using one of three synthetic methods. Among the compounds investigated, 1H-3-(4-sulfamoylphenyl)-4-phenyl-pyrrole-2,5-dione (6l) showed a strong inhibitory activity (IC₅₀ = 0.61 μM) of PGE₂ production.     

Alarm behaviour in Eciton army ants

The effective communication of alarm can be critical for social animals so that they are able to deal with threats posed by predators and competitors. In the case of many of the most ecologically dominant, large‐colony ant species, these alarm responses are aggressive and coordinated by alarm pheromones, produced generally from the mandibular glands. In the present study, the alarm behaviour of two Neotropical army ant species is examined, the swarm raiding Eciton burchellii (Westwood) and the column raiding Eciton hamatum (Fabricius). Both species exhibit aggressive alarm responses in response to crushed heads, suggesting that the alarm pheromone is indeed produced by the mandibular glands in these ants. The most abundant component of the mandibular gland secretion, 4‐methyl‐3‐heptanone (10 µL on a rubber septum), stimulates a substantial alarm response, although this is less than the response to a single crushed head. This suggests that 4‐methyl‐3‐heptanone may be an alarm‐stimulating compound in Eciton. The alarm response of E. burchellii involves more workers than that of E. hamatum, although major workers play a much greater role in the response of the latter species. The differences in the alarm response of the two closely‐related species may relate to their foraging strategies, with E. burchellii relying more on quantity rather than the caste of ants responding and possibly using alarm pheromones for offensive as well as defensive functions.     

Evaluation of Antituberculosis Activity and in Silico Properties of Oxymethylene-cyclo-1,3-diones

Tuberculosis is a leading infectious disease that has infected one-third of the world's population and is more prevalent among people belonging to developing countries such as India and China. In the present study, a series of substituted oxymethylene-cyclo-1,3-diones was synthesized and screened for anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv (M. tuberculosis). The compounds were synthesized by condensation of 1,3-cyclicdione, substituted phenols/ alcohols and triethyl orthoformate. The synthesized compounds were screened for anti-tuberculosis activity against M.tuberculosis H37Rv using Middlebrook 7H9 broth assay. Results demonstrated that among the synthesized library of molecules, two compounds 2-(2-hydroxyphenoxymethylene)-5,5-dimethylcyclohexane-1,3-dione and 5,5-dimethyl-2-(2-trifluoromethylphenoxymethylene)cyclohexane-1,3-dione were found to be most active against M. tuberculosis (MICs of 1.25 μg/mL⁻¹). The MICs of 2-(2,4-difluoro-phenoxymethylene)-5,5-dimethylcyclohexane-1,3-dione and 2-(2-bromophenoxymethylene)-5,5-dimethylcyclohexane-1,3-dione were found to be 5 and 10 μg mL⁻¹, respectively. Data from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that all the four most active compounds did not exhibit cytotoxicity against human cell lines. Molecular docking studies revealed that the most active compound targets mycobacterial InhA enzyme. In summary, the present study demonstrates the methodology for the synthesis of oxymethylene-cyclo-1,3-diones and identified two potential anti-tuberculosis compounds.     

The antimicrobial activity of the mandibular gland secretion of a formicine ant, Calomyrmex sp. (Hymenoptera: Formicidae)

The mandibular gland secretion from mature workers of the formicine ant Calomyrmex sp. exhibits strong antimicrobial activity when tested against selected soil microorganisms. The activity against bacteria is both inhibitory and bacteriocidal while that against fungi is inhibitory. The white secretion from young workers appears to be much weaker in its antibiotic effects.     

The alerting pheromones of the honeybee

Summary When honeybees sting an object they release pheromones that direct the attack of other bees towards it. 2-heptanone is the principal aggression-provoking component in the secretion of the mandibular gland. Isoamyl acetate is not the only active component of the aggression-provoking secretion at the base of the sting but no such component occurs in the venom itself.

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Zusammenfassung Wenn Honigbienen stechen, lassen sie Pheromone frei, die andere Bienen zum Angriff gegen das Objekt veranlassen. Das 3-Heptanon ist das vornehmste zum Angriff reizende Sekret der Mandibeldrüse. Das Isoamylazetat ist nicht der einzige wirksame Bestandteil des zum Angriff reizenden Sekrets an der Stachelbasis, aber im Gift selbst ist kein ähnlich wirkender Bestandteil vorhanden.

     

Alkylpyrazines: alarm pheromone components of the little fire ant, Wasmannia auropunctata (Roger) (Hymenoptera, Formicidae)

The previous identification of 2,5-dimethyl-3-(3-methylbutyl)pyrazine as the mandibular alarm pheromone of the little fire ant Wasmannia auropunctata (Roger), has been found to be incorrect. Gas chromatography–mass spectrometry (GC/MS) of ant extracts suggested the correct structure to be the regioisomer 2,5-dimethyl-3-(2-methylbutyl)pyrazine, which was confirmed by comparison with the synthetic pyrazine. GC/MS analysis also revealed the presence of an additional disubstituted alkylpyrazine which was identified as 3-methyl-2-(2-methylbutyl)pyrazine. Headspace sampling of confined ants with SPME and Porapak Q followed by GC/MS analysis showed 2,5-dimethyl-3-(2-methylbutyl)pyrazine as the major volatile released by W. auropunctata workers while 3-methyl-2-(2-methylbutyl)pyrazine was only detected in trace amounts. In laboratory bioassays, W. auropunctata workers were attracted and arrested by both pyrazines, although the results were not always consistent. Synthetic pyrazines generally attracted as many W. auropunctata workers as were attracted to a single crushed ant. However, higher numbers of W. auropunctata were arrested by crushed ant treatments than by synthetic pyrazines in all bioassays but one.     

Synthesis,in-vitro α-glucosidase inhibition,antioxidant, in-vivo antidiabetic and molecular docking studies of pyrrolidine-2,5-dione and thiazolidine-2,4-dione derivatives

α-Glucosidase is considered as a therapeutic target for the treatment of type 2 diabetes mellitus (DM2). In current study, we synthesized pyrrolidine-2,5-dione (succinimide) and thiazolidine-2,4-dione derivatives and evaluated for their ability to inhibit α-Glucosidase. Pyrrolidine-2,5-dione derivatives (11a–o) showed moderate to poor α-glucosidase inhibition. Compound 11o with the IC₅₀ value of 28.3 ± 0.28 µM emerged as a good inhibitor of α-glucosidase. Thiazolidine-2,4-dione and dihydropyrimidine (TZD-DHPM) hybrids (22a–c) showed excellent inhibitory activities. The most active compound 22a displayed IC₅₀ value of 0.98 ± 0.008 µM. Other two compounds of this series also showed activity in low micromolar range. The in-vivo antidiabetic study of three compounds 11n, 11o and 22a were also determined using alloxan induced diabetes mice model. Compounds 11o and 22a showed significant hypoglycemic effect compared to the reference drug. In-vivo acute toxicity study showed the safety of these selected compounds. In-silico docking studies were carried out to rationalize the in-vitro results. The binding modes and bioassay results of TZD-DHPM hybrids showed that interactions with important residues appeared significant for high potency.     

The ontogenetic pattern of mandibular gland components in queenless worker bees (Apis mellifera capensis Esch.)

The quantity and composition of the six major mandibular gland components of young queenless workers of the Cape honeybee (Apis mellifera capensis) were determined. The total amount of the six components increased with age. The relative quantities in the mandibular gland secretion of queenless caged workers were found to change rapidly during the first 4 days after emergence and to become dominated by the queen substance, 9-keto-2(E)-decenoic acid. Also the relative amounts of 9-hydroxy-decenoic acid, a precursor of the queen substance, showed an increase of an order of magnitude within the first 4 days of imaginal life. The relative amounts of the aromatic compounds typical to the queen pheromone remained similar in this developmental time window. The increase of queenlike compounds is particularly strong between days two and three after emergence. These queen-like pheromones play a major role in the development of reproductive hierarchies among workers under queenless conditions. This may be an important factor in the socio-parasitic pathway of A. m. capensis.