Weaver ant, Oecophylla smaragdina (Hymenoptera: Formicidae) headspace volatiles deter oviposition in female Oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Natural predator–prey interactions in the insect world provide interesting insights into how female herbivores avoid ovipositing in places where a predator’s presence can be perceived. Several insects show such innate behavioural traits that can be harnessed to formulate safe pest management strategies in agriculture. Using customized oviposition assays, we studied the innate ovi­position avoidance behaviour of the oriental fruit fly, Bactrocera dorsalis, a frugivorous pest. Fruit flies preferred to lay eggs in a test region smeared with g-octa­lactone (an oviposition stimulant used as a positive control) over one smeared with a mix of g-octalactone and headspace volatiles of the weaver ant, Oecophylla smaragdina, a generalist predator in orchard ecosystems. A combination of the electrophysiologically active odour cues n-undecane and n-tridecane from the headspace volatiles of weaver ants was found to deter female fruit flies from ovipositing. Using these behaviour-modifying chemicals in a blend as a pre-harvest spray could potentially prevent egg-laying by the oriental fruit flies in ready-to-harvest fruits