Ant, thief

Besides piperidine alkaloids, a total of 19 pyrrolidines have been found in the secretions of thief ants and fire ants of the genera Solenopsis and Monomorium. Among these, compounds 80-84 are simple pyrrolidines with two saturated linear all-carbon side chains only in Solenopsis latinode is there a secondary amine (82) and its methylated analog (85). One or two terminal unsaturations are present in compounds 86-91, which all possess a (hex-l-en)-6-yl chain and a 5-, 7-, or 9-carbon saturated chain. Compounds 93, 94, 96, 97, and 98 are the A-l-pyrrolines corresponding to pyrrolidines 80, 82, 90 (93 and 96 corresponding to 80, 94 to 82, and 97 and 98 to 90). 

Workers of pharaoh s ant, Monomorium pharaonis, utilize their poison gland secretion as an effective repellent in the same way as that of thief ants, Solenopsis (Diplorhoptrum) species, in order to steal brood from the nests of other... 

Solenopsis (Diplorhoptrum) conjurata and some other thief ants contain indo-lizidines and/or piperidines (Tables I and II). (5Z,8 )-3-Heptyl-5-methylpyr-rolizidine (48) has also been shown to be contained in the thief ant Solenopsis xenovenenum (Table IV). The poison glands of Aphaenogaster fulva and A. tennesseensis contain the tobacco alkaloid anabaseine (8), which functions as an attractant in A. fulva (Table I) (26). 

The structure of monomorine I (16a), isolated from the extract of workers of the thief ant, Monomorium pharaonis, by gas-liquid chromatography (Table II), has been revealed to be 3-butyl-5-methyloctahydroindolizidine on the basis of mass and H-NMR spectra. The mass spectmm shows characteristic peaks at m/z 180 (345 M - CH3) and m/z 138 (346 M - Bu, a base peak), indicating the presence of methyl and butyl group attached to the a carbons of an amine, in addition to a molecular ion at m/z 195. The fact that the (M — 1) peak is higher than the M peak indicates a cyclic amine. The H-NMR spectmm shows two methyl groups (triplet at 8 0.88, CH3—CH2 doublet at 8 1.18, CH3CH—N) and three methines adjacent to nitrogen (8 2.13, 2.27, and 2.52). 

Stractures of 3-alkyl-5-methylindolizidines, found in thief ants, Solenopsis species (Table II), arrived at by gas chromatographic and mass spectral analysis were confirmed by coinjection and direct comparison with the synthetic sample. Indolizidine 15a from S. conjurata exhibits characteristic peaks at miz 152 (M — CHj) and 138 (M — C2H5, a base peak) as well as a parent peak at m/z 167 in the mass spectram. It corresponds to an isomer of 3-ethyl-5-methylindolizidine (15) which was prepared as a mixture of four stereoisomers by reductive amination of triketone 391 with ammonium acetate-sodium cyanoborohydride and sodium borohydride (Scheme 47). 

A related oxime 304 was prepared for the total synthesis of 305, an unusual pyrrolizidine alkaloid isolated from the venom of a variety of thief ant... 

The principal component of the secretion of the poison gland of the European thief ant (Solenopsis fugax) is rrarcs-2-n-butyl-5-n-heptylpyrrolidine, identified by mass spectrometry and synthesis.5 The reductive amination of 1,4-diketones with sodium cyanoborohydride and ammonium acetate has yielded various 2,5-dialkyl-pyrrolidines that occur in the poison glands of ants of Monomorium spp.6... 

Cleptobiotic Ectatomma ruidum Thief ants matching with Jeral et al., 1997... 

Jeral, J.M., Breed, M.D. and Hibbard, B.E. (1997). Thief ants have reduced quantities of cuticular compounds in a ponerines ant Ectatomma ruidum. Physiol. Entomol., 22, 207-211. 

The venomous constituent of the cryptic thief ant, Solenopsis xenovenenum, has been identified as the 3-heptyl-5-methylpyrrolizidine (50) from its mass spectrum and the fact that a related pyrrolidine (51) has been isolated from another species of ant.47 This is the first reported occurrence of a 3,5-dialkyl-pyrrolizidine, and its structure was confirmed by synthesis. Reductive amination of the known triketone (52) with sodium cyanoborohydride and ammonium acetate gave a mixture of four isomers of 3-heptyl-5-methylpyrrolizidine, which were separated by preparative g.l.c. The stereochemistry of the ring-junction of each isomer was established from its i.r. and n.m.r. spectra. 

Alkaloids have only been identified in the venoms of ant species in the Myrmicinae, the largest of the formicid subfamilies. This diverse subfamily includes fire ants and harvester ants, the species of which produce highly algogenic venoms. In addition, this ant taxon includes thief ants and... 

The disubstituted pyrrolidines and piperidines have been demonstrated to be excellent repellents for ants under field conditions. Workers of Monomorium pharaonis effectively repel other species of ants with venom droplets which accumulate on the tip of the sting (37), a strategy that is used with equal success by workers of North American Monomorium species ( 38.) and the European thief ant, Solenopsis fugax (37). The venom of the latter species contains a single alkaloid, trans-2-butyl-5-heptylpyrrolidine (I, m=3, n=6) (1 ), and the... 

Disubstituted pyrrolizidines were first discovered in Nature as constituents from ants (121). The structure of (5Z,8 )-3-heptyl-5-methyl-pyrrolizidine from thief ant (Solenopsis xenovenenum) venom proved identical with the amphibian pyrrolizidine 5Z,8 -223H (Fig. 10). Other pyrrolizidines from ants include (5 ,8Z)-3,5-di(5-hexenyl)pyrrolizidine, (5Z,8 )-3-methyl-5-(8-nonenyl)pyrrolizidine, and (5 , 8Z )-3-(8-nonenyl)-... 

Three new diastereomers of 3-hexyl-5-methylindolizidine, (5Z,9Z)-, (5E,9E)- and (5Z,9 ), Fig. (8), were identified in different collections of thief ants Solenopsis (Diplorhoptrum) species from Cahfomia. The identification of these alkaloids resulted from the analysis of their MS spectra and comparison of their GC-FTIR spectra. The authors also emphasised the chemotaxonomic value of the stereochemistry of these alkaloids [23]. 

In addition to a number of piperidine alkaloids, at least 19 pyrrolidine alkaloids have been reported from secretions of thief ants and fire ants of the genera Solenopsis and Mono-morium. In general, these compounds occur in minute amounts (50 xg/ant) (Jones and Blum, 1983 Massiot and Delaude, 1986 Numata and Ibuka, 1987). 

Pyrrolizidine alkaloids also have been found in amphibians. Certain of these amphibian alkaloids also occur in insects. For example, the venom of the thief ant, Solenopsis xenovenenum, is an amphibian pyrrolizidine (Daly et al., 1993). 

Ants have developed various ways to overcome their prey. Examples of slave-making ants, thief ants and crypsis in ants are now well known. Ants invade termite nests, forage on them and return to their own colony without being molested. How can this occur ... 

Like D. uelense ants, Solenopsis fugax ants and Nomada bees have developed a way of predation which permits them to invade and steal brood from their prey. The European thief ants S. fugax, steal brood from nearby nests of other ant colonies by building a system of subterranean tunnels which lead to the nest of their prey. Scout ants lay down trail pheromone from the Dufour s gland to attract nest mates... 

Another group of Solenopsis (thief ants) and some species of Mono-morium ants have alkyl-pyrrolidines and -pyrrolines (Figure 9.7). The sting of these ants does not seem to be so painful, but whether this is due to the alkaloids or the protein part of the sting is not known. More recently some of the same and similar pyrrolidines have been found in Megalomyrmex ants. Their biosynthesis is not yet known. 

Figure 9.7 Alkyl- and alkenyl-pyrrolines, -pyrrolidines and N-methylpyrrolidines of unknown origin from Solenopsis thief ants and some Monomorium ants...

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