Effect of synthetic aphid alarm pheromone (E) -beta-farnesene on development and reproduction of Aphis gossypii (Homoptera: Aphididae).

The synthetic aphid alarm pheromone (E)-beta-farnesene (EBF) is released by aphids in response to predation or other disturbances that occur in the colony. This is presumed to benefit the population by allowing increased survival of related individuals taking successful evasive action after perception of the pheromone. The effect of pheromone perception by aphids in the absence of real threats was investigated to determine the baseline effect of this communication on aphid survival, development, and fecundity in the laboratory. All four nymphal stages of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), were stimulated with EBF. No significant difference in survival rates was observed in the aphids stimulated with EBF compared with the untreated control. Developmental times of the aphids were significantly prolonged in first and third instars when they were stimulated with EBF. Significantly lower fecundity and lighter weight of adult aphids were observed in aphids stimulated with EBF at as first instars compared with untreated controls and other instars. Results indicate that exposure of the first instar of A. gossipii to the synthetic alarm pheromone adversely affects subsequent development and fecundity of the population. This reduces aphid fitness that must be compensated by increased survival from predation for the pheromone to confer a selective advantage to the species.