Molecular basis of Morinda citrifolia (L.): toxicity on Drosophila

The ripe fruit of Morinda citrifolia, host plant for Drosophila sechellia is highly toxic for three closely related species (D. melanogaster, D. simulans, and D. mauritiana). Green and rotten fruits are not toxic for all species tested. Short fatty acids were found to be present in large quantities in the extract of the ripe fruit. The most abundant (octanoic acid) was tested pure for its toxicity in a dose-dependent manner; D. sechellia is five to six times more resistant than D. melanogaster to octanoic acid. Octanoic acid alone seems to be sufficient to explain the toxic effect of the pulp. It is less abundant in the rotten fruit and absent in the green fruit