CHEMISTRY OF VENOM ALKALOIDS IN SOME SOLENOPSIS (DIPLORHOPTRUM) SPECIES FROM PUERTO-RICO

A number of 15-carbon alkaloids have been identified in venom extracts of four Puerto Rican species of ants in the genus Solenopsis (Diplorh optrum). Workers of a species from El Verde produced the cis and trans isomers of 2-methyl-6-nonylpiperidine with the latter isomer predomin ating. The same compounds were identified in queens of a species from Rio Grande, but in this species no alkaloids were detected in worker e xtracts. Workers of a Diplorhoptrum species collected on Mona Island p roduced primarily a trans-2-methyl-6-(Z-4-nonenyl)piperidine, 3, with smaller amounts of the cis isomer, whereas the major compound found in the queens of the same species on Mona Island was (5Z,9Z)-3-hexyl-5-m ethylindolizidine, identical with the alkaloid produced by queens of a species collected on Cabo Rojo. Surprisingly, workers of the Cabo Roj o species produced (5Z,9Z)- and (5E,9E)-3-butyl-5-propylindolizidine ( 4 and 5, respectively) reported earlier as the 223AB indolizidines fro m skins of dendrobatid frogs. The possible significance of the qualita tive and quantitative differences in the venom alkaloids synthesized b y queens and workers is discussed as is the possibility that ants cont aining such alkaloids may serve as a dietary source for the skin alkal oids used by certain frogs in chemical defense.