Biological activity of synthetic hydrocarbon mixtures of cuticular components of the female housefly (Musca domestica L.)

Mixtures of (Z)-9-alkenes (C₂₁-C₃₃), n-alkanes (C₂₁-C₃₃), and mono- and dimethylalkanes (C₂₇, C₂₉), as components of the cuticular lipids washed from the female housefly (Musca domestica L.), were synthesized and assayed for their biological activity on male houseflies. The (Z)-9-alkenes and their hydrogenated n-alkanes were synthesized from jojoba wax components by the appropriate chain elongation. The methylalkanes were prepared by Grignard coupling reaction of the appropriate alkyl halides, catalyzed by Li₂CuCl₄. Six- to 7-day-old virgin male houseflies exhibited the highest mating strike activity toward 6- to 7-day-old virgin females. The mating strike activity of the synthetic hydrocarbons was studied by exposing 6- to 7-day old virgin males to petrol-ether-rinsed 1 to 2-day-old dead females treated with these chemicals. (Z)-9-Tricosene was the most active hydrocarbon tested when it was applied in amounts of 10 μg to a washed dead female. Amounts of 5 μg of (Z)-9-tricosene did not cause sexual activity in the males. Mixture of (Z)-9-alkenes showed low activity when applied at 10-μg amounts. However, when mixtures were made of 5 μg of (Z)-9-tricosene with 5 fig of each of certain mixtures of (Z)-9-alkenes, the striking activity became as high as that of 10 μg of (Z)-9-tricosene. This might be a synergism effect. The mixtures of n-alkanes, as well as the mono- and dimethylalkanes, showed moderate activity. When (Z)-9-tricosene was added to these materials no increase in male activity was observed.