Chemical Odorant of Colonial Seabird Repels Mosquitoes

Abstract

The crested auklet, Aethia cristatella, emits a class of aldehydes shown to be potent invertebrate repellents when used by heteropterans against their predators. Our aim was to determine the efÞcacy of these aldehydes against mosquitoes in the laboratory. Synthetic analogues of the auklet odorant were strongly repellent to mosquitoes in controlled laboratory trials. Furthermore, the efÞcacy was similar to previous reports for commercial mosquito repellents. These results, in combination with a previously published study, show that constituents of the aldehyde odorant are broad spectrum in efÞcacy against ectoparasitic arthropods of birds. Our report is the Þrst empirical evidence for an endogenous mosquito repellent in birds.

Identification of non-host semiochemicals for the brown dog tick, Rhipicephalus sanguineus sensu lato (Acari: Ixodidae), from tick-resistant beagles, Canis lupus familiaris

“…The same authors also found this blend of odorant provided significant repellency against nymphal seabird ticks, Ixodes uriae (White), a tick that parasitises auklets, and that octanal provided highly significant repellency. Subsequently, it was found that octanal even caused repellency in A. aegypti that was significantly greater when presented alone, as opposed to in the blend of the odorant (Douglas et al, 2005).…”

Prenuptial perfume: Alloanointing in the social rituals of the crested auklet (Aethia cristatella) and the transfer of arthropod deterrents

“…The highest concentrations were 6.0 μg/cm 2 for hexanal, 9.5 μg/cm 2 for octanal, 20.6 μg/ cm 2 for (Z)-4-decenal, and 29.5 μg/cm 2 for decanal. These surface concentrations were much greater than previous bioassays that were repellent to mosquitoes (e.g., octanal 0.048-0.052 μg/cm 2 , 1% treatment, Douglas et al 2005).…”

“…The head is the body region where birds are most vulnerable to ectoparasites, such as ticks (Reed et al 2003). The crested auklet's odorant is effective at deterring ticks and mosquitoes (Douglas et al 2004(Douglas et al , 2005. It is interesting that alloanointing is often followed by mutual preening.…”

“…The crested auklet's odorant is dominated by a series of even-numbered, 6-12 carbon aldehydes (21.4% nhexanal, 40.7% n-octanal, 3.4% n-decanal, 8.2% (Z)-4-decenal, 7.5% (Z)-4-dodecenal, 7.5% (Z)-6-dodecenal and putative oxidation products hexanoic acid 7.7% and octanoic acid 3.5%; Douglas et al 2001aDouglas et al , 2004. Synthetic constituents of the odorant repel ticks and mosquitoes in a dose-dependent fashion (Douglas et al 2004(Douglas et al , 2005. It is interesting to note that some of these same compounds have been isolated from the volatile emanations of human skin, and in this context, they are regarded as attractant inhibitors of ectoparasitic arthropods (Bernier et al 2006).…”

The citrus-like scent of crested auklets: reviewing the evidence for an avian olfactory ornament

“…However, the immediate and lethal impact of two odor compounds (octanal and Z-4-decenal) on two genera of auklet feather lice (Quadraceps, Austromenopon; Douglas et al 2004) involved highly concentrated treatments that were thousands of times that of natural plumage (Hagelin and Jones 2007;Hagelin 2007, p. 95). It is unclear whether the data documenting the dosedependent repellency of mosquitoes (Douglas et al 2005b) and two species of ticks (Douglas et al 2004) reflects a range of concentrations that ectoparasites would normally experience on a single bird in the wild (Hagelin 2007;Hagelin and Jones 2007).…”