Crematogaster

In addition, the all-(S) absolute configuration of the Subcoccinella 24-punctata macrocycles was determined by chiral GC-MS comparison of derivatives of the natural material with optically pure synthetic samples [56]. Furthermore, it was demonstrated that this secretion serves as a potent antipredator defense contact with it elicited pronounced cleaning activity by the predatory ant Crematogaster lineolata. Additionally, application of the secretion to palatable food items rendered them unacceptable to the ant [58]. 

Fig. 22 Structures of electrophilic poisons from the Dufour gland of European Crematogaster ants...

Scheme 1 Hypothetical formation of lactols and a-angelica lactones in Crematogaster ants...

More recently, three as yet unidentified species originating from Papua New Guinea have also been studied. Crematogaster sp. 1 was shown to contain, besides C25 homologs of the 4-oxo-2,5-dienals (131), a series of derivatives, whose structures were determined to be 135a-f, on the basis of a complete ID and 2D NMR study at 600 MHz (Fig. 23) [136]. 

Fig. 23 Structures of Dufour gland components of New Guinean Crematogaster ants...

In contrast with all the other species of Crematogaster studied till now, the venom of C. sp. 2 from Papua New Guinea did not contain mixtures of homologous compounds. Two derivatives, 136 and 137, characterized by the presence of a conjugated triene on one end of the chain, and by a 1,3-hydroxyketone at the other end, were isolated from this species (Fig. 23). These structures could constitute biosynthetic intermediates en route to the cross-conjugated dienone system. The venom of C. sp. 3 contained 4-oxo-2,5-dienyl acetates similar to... 

Fig. 25 Cembrane derivatives from New World Crematogaster ants...

Fig. 26 Structures of trihydroxycyclohexane derivatives from an African Crematogaster ant...

R) and (S)-3-octanol, (i )-2-dodecanol, (i )-2-methyl-4-heptanol and (i )-2-methyl-4-octanol, the pheromones of Myrmica scabrinodis, Crematogaster castanea, C. liengmei, C. auberti and Metamasius hemipterus were synthesized starting from nonracemic P-hydroxy sulfides. 

Not only queens express these profiles. Intermediate forms between queen and worker castes, so-called intermorphs, specialize in trophic egg-laying in Crematogaster smithii (Heinze etal., 1999). Interestingly, they produce a queen-like profile, while workers produce a profile that differs from those of reproductive queens and intermorphs (Oettler et al., 2008). 

Heinze, J., Foitzik, S., Oberstadt, B., Rueppell, O. and Holldobler, B. (1999). A female caste specialized for the production of unfertilized eggs in the ant Crematogaster smithi. Naturwissenschaften, 86, 93-95. 

Oettler, J., Schmitt, T., Herzner, G. and Heinze, J. (2008). Chemical profiles of mated and virgin queens, egg-laying intermorphs and workers of the ant Crematogaster smithi. J. Ins. Physiol., 54, 672-679. 

The lack of intense interactions may also explain the reciprocal tolerance and the lack of chemical mimicry of the cuticular profiles in the occasional parabiotic associations between Camponotus morosus and Solenopsis gayi or Crematogaster-Camponotus (Errard et al., 2003 Menzel et al., 2008). 

Menzel, F Linsenmair, K. E. and Bliithgen, N. (2008). Selective interspecific tolerance in tropical Crematogaster-Camponotus associations. Ann. Behav., 75, 837-846. 

Figure 12 Crematogaster ants make the simplest carboxylic acid, formic acid. Notice the structure of the —COOH group.

Figure 16 Fatty acid derivatives from New Guinean and Braziiian Crematogaster species.

---