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Chemical investigations of exocrine glands in some Myrmica and Attine ants

Chemical investigations of exocrine glands in some Myrmica and Attine ants Thumbnail


Abstract

By employing a combination of microanalytical techniques including solid sampling, reaction gas chromatography, gas chromatography^ bioassay and linked gas chromatography-mass spectrometry, the volatile constituents of the venom, Dufour and mandibular glands of workers of eleven species of myrmicine ant (including two sub-species) have been examined.
Trail following behaviour in the ant MU rubra is evoked by a single substance, 3-ethyl-2,5-dimethylpyrazine, identified from the venom of this species. Seven other Myrmica species which follow trails made with each other's venom also produce this substance in similar quantities. Analysis of ten single venom glands by a solid sampling technique showed M. rubra workers to contain on average 5.8+ 1.7ng of the trail substance.
The same solid sampling technique has been used to quantify the major trail pheromone components in A. octosplnosus, A. cephalotes, A. s. sexdens and A. s. rubropilosa.
The Dufour glands of the above Attines and those of M. ruginodis, M. sabuleti and M. 1obicornis have been shown to contain species specific blends of either predominently linear or terpenoid hydrocarbons in the C12 to C23 chain length range. In common with M. rubra the major glandular component of M. ruginodis is heptadecene, while M. sabuleti and JK. lobicornis, like scabrinodls, produce predominently farnesene and homologous terpenoid hydrocarbons. Of the Attines, JV. octosplnosus also produces terpenoid material, homofarnesene is its major glandular component. A. cephalotes on the other hand contains mainly n-heptadecane. There are quantitative differences in the hydrocarbon compositions of the two sexdens sub-species. The major glandular component of A. s. sexdens is (Z)-9-tricosene, while in A. s. rubropilosa the most abundant component is (Z)-9-nonadecene. From a chemical taxonomic viewpoint A. s. rubropilosa and A. s. sexdens could be regarded as separate species.
All the above species produce microgram amounts of hydrocarbon material in their Dufour glands with the exceptions of A. octospinosus and _A. cephalotes which produce nanogram quantities. In the Attines there is a linear relationship between body size and hydrocarbon content.
The mandibular glands of M. schencki, M. rugulosa, M. sulcinodls, M. ruginodis, M. sabuleti and M. lobicornis have been shown to contain microgram amounts of similar mixtures of compounds in species specific proportions. The mixtures are composed of the same 3-alkanones and 3-alkanols in the C5 to C10 chain length range that are found in M. rubra and M. scabrinodis. The highly volatile portion of this secretion in these latter two species consists mainly of ethanal, propanone and methylpropanal. The identification of methylpropanal has required a correction be made to previous work. Nanogram quantities of these three compounds are found in similar proportions in the mandibular glands of other Myrmica species.

Publicly Available Date Mar 28, 2024

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