Host Selection by Hylemya antiqua: 1 Identification of Oviposition Stimulants Based on Proposed Active Thioalkane Moieties 2

Abstract

Based on previous studies which identified onion-produced oviposition stimulants for the onion maggot, Hylemya antiqua (Meigen), it was hypothesized that a common thiopropyl functional group was responsible for olfactory receptor stimulation. Experimental examination of this hypothesis revealed specifically the requirement of a single sulfur atom with 2 unshared electron pairs, bonded 10 a saturated hydrocarbon chain 3–5 carbons long. Associated groups compatable with the active structures ranged from a single hydrogen as in propanethiol, to saturated and unsaturated hydrocarbon chains 1–5 carbons long. Molecular moieties nullifying the oviposition inducing properties of the active structures were observed in propyl thiocyanate, dipropyl sulfoxide and propionaldehyde dipropylthioacetal. New oviposition stimulants identified on the basis of the initial and revised hypothesis are: dipropyl sulfide, cis - and trans -propenyl propyl sulfide, methyl propyl sulfide, dibutyl disulfide, methyl butyl disulfide, dipentyl disulfide, dipropyl trisulfide, 2-butyl propyl sulfide and butanethiol.