Aromatherapy on a large scale: exposing entire adult holding rooms to ginger root oil increases the mating competitiveness of sterile males of the Mediterranean fruit fly in field cage trials

Abstract The sterile insect technique (SIT) is widely used in integrated programs against fruit fly pests, particularly the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Unfortunately, the mass‐rearing procedures inherent to the SIT often lead to a reduction in male mating competitiveness. One potential solution involves the pre‐release exposure of males to specific attractants. In particular, male exposure to ginger root oil [ Zingiber officinale Roscoe (Zingiberaceae); hereafter GRO] has been shown to increase mating success dramatically in field cage trials. Initial studies exposed small groups of males (25 individuals), but more recent work has demonstrated that GRO exposure involving standard storage boxes (containing ≈ 36 000 males) also results in enhanced mating performance. The objective of the present study was to determine whether aromatization of entire trailers, holding ≈ 14 million sterile males from a genetic sexing [temperature sensitive lethal ( tsl )] strain, increases male mating success. Independent of the total dose, spatial distribution, or type of dispenser used, sterile males exposed to GRO for a 24‐h period displayed greater mating success than non‐exposed males in mating cage trials (in which tsl males competed against males from a standard, bisexual strain for females from this same standard strain). Averaged over all experiments, tsl males exposed to GRO obtained 54% of all matings compared to 38% for non‐exposed tsl males, an increase of 42%. The implications of these findings for SIT programs against C . capitata are discussed.