Pergandei

Venoms from the fire ants Solenopsis invicta and 5. geminata are free of detectable histamine but possess histamine-release activity. This activity can account for the edema, itch, redness, warmth, and possibly the pain and burning sensations resulting from fire ant stings. And it can be attributed to the piperidines which constitute the major component of the venom. It has actually been proved that 6-methyl-2-n-undecylpiperidines (Ic and Id), components of S. geminata, possess the histamine-release activity (75). Due to some of the above-mentioned various activities the piperidine alkaloids play roles as defensive compounds. In addition to 2-alkyl-6-methylpiperidines, their N-methyl derivatives (3) are found in S. pergandei, S. carolinensis, and S. conjurata, and 1-piperideine derivatives (6 and 7) in S. sp. A (Puerto Rico) and S. xyloni (Table I). 

The structures of the A-methyl-2,6-dialkylpiperldines (3b and 3c), found in S. pergandei and S. carolinensis (Table I), are indicated by a base peak (242) of w/z 112 as well as the parent peaks in their mass spectra. Structures were confirmed by their identity with authentic samples which were prepared by reductive methylation of the corresponding A -H piperidine with formaldehyde and formic acid (16). 

The chemical nature of the Harpagoxenus substances is unknown, but the main components from Formica pergandei and F. subintegra are decyl, dodecyl and tetradecyl acetates. These substances originate in the hypertrophied... 

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