title: Interspecific differences in Aethia spp. auklet odorants and evidence for chemical defense against ectoparasites.
abstract: The true auklets (Genus Aethia) are small planktivorous seabirds of the Bering Sea and North Pacific. Two species, the crested and whiskered auklets produce volatile citrus-like odorants. We here show that the whiskered auklet odorant is composed predominantly of two odd-numbered aldehydes (heptanal and nonanal) with no detectable unsaturated aldehydes. By comparison the crested auklet odorant is dominated by even-numbered aldehydes, both saturated and monounsaturated, ranging in size from 6 to 12 carbons. This is evidence of species-specific acquisition or biosynthetic pathways. We clarify the chemistry of the crested auklet odorant. We cite evidence that the C-12:1 aldehyde in crested auklets is actually two isomers, (Z)-4-dodecenal and (Z)-6-dodecenal. We also report on experimental evidence that aldehyde constituents kill and repel ectoparasites. Efficacy of the aldehydes may increase when they are combined in a mixture. The repellency of the mixture increases with chemical concentration. This suggests that individuals with higher chemical production are likely to repel ectoparasites more effectively.
authors.affiliation: Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA. douglas@ims.uaf.edu
authors.forename: Hector D
authors.initials: HD
authors.lastname: Douglas
authors.forename: Jason E
authors.initials: JE
authors.lastname: Co
authors.forename: Tappey H
authors.initials: TH
authors.lastname: Jones
authors.forename: William E
authors.initials: WE
authors.lastname: Conner
mesh_terms: D000447:Aldehydes / Q000737:chemistry* / Q000627:therapeutic use*; D000818:Animals; D001715:Bird Diseases / Q000469:parasitology / Q000517:prevention & control*; D001717:Birds; D004478:Ectoparasitic Infestations / Q000469:parasitology / Q000517:prevention & control* / Q000662:veterinary; D007536:Isomerism; D009812:Odorants; D013045:Species Specificity
chemical_list: D000447:Aldehydes