Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 2/3/2007
Publication Date: 4/3/2007
Citation: Weldon, P.J., Carroll, J.F. 2007. Vertebrate chemical defense: secreted and topically acquired deterrents of arthropods. In: Debboun, M., Frances, S.P., and Strickman, D., editors. Insect repellents: principles, methods, and uses. Boca Raton, FL:CRC Press. p. 47-75. Interpretive Summary: Repellents are important means of protecting humans from noxious organisms. In natural systems, repellents produced and acquired by a variety of mammals, birds, reptiles and amphibians protect them from blood-feeding, biting and stinging insects, ticks and mites. This book chapter reviews and interprets what is known about substances used by vertebrates to deter attack by parasitic and predatory arthropods. Some deterrent substances are produced by the skin and others are acquired by animals or birds rubbing against certain plants. Naturally occurring repellents may be a source of chemicals that could be developed into products that could be used to protect humans and agricultural animals. This chapter is of interest to scientists studying behavior and chemical ecology, as well those involved in developing personal protection products.
Technical Abstract: Arthropods profoundly affect the fitness of terrestrial vertebrates. Some arachnids, centipedes, and insects opportunistically prey on small tetrapods. Some social hymenopterans launch massive foraging swarms and fiercely defend their colonies via stinging or biting attacks. Pelage- or plumage-degrading arthropods, such as feather lice, compromise the insulative and other essential properties of the integument, and may ultimately compromise the survivorship or fecundity of their hosts. More seriously, feeding by hematophagous insects, mites, and ticks weakens and occasionally exsanguinates hosts. Many of these ectoparasites transmit debilitating or lethal pathogens. The potent agencies of natural selection represented by predatory, aggressive, and ectoparasitic arthropods have forged in tetrapods an array of defensive adaptations. We review evidence for chemicals used by amphibians; reptiles, including birds; and mammals against arthropods, and describe the sources and nature of the relevant chemicals they secrete. We focus on the involvement of chemosensory-mediated effects, rather than those involving mechanical defense against attack, e.g., adhesives. We also examine active or self-anointing, where scent-laden materials are rubbed onto the integument, and passive anointing or fumigation, where emitted chemicals are superficially adsorbed, as mechanisms by which tetrapods may acquire chemicals to combat arthropods. These deterrent chemicals may be sources for products that can be used to protect humans and domesticated animals from attack by arthropods.