Intraspecific directed deterrence by the mustard oil bomb in a desert plant

Michal Samuni-Blank, Ido Izhaki, M. Denise Dearing, Yoram Gerchman, Beny Trabelcy, Alon Lotan, William H. Karasov, Zeev Arad

Research output: Contribution to journalArticlepeer-review


Plant secondary metabolites (SMs) acting as defensive chemicals in reproductive organs such as fruit tissues play roles in both mutualistic and antagonistic interactions between plants and seed dispersers/predators [1-5]. The directed-deterrence hypothesis states that SMs in ripe fruits deter seed predators but have little or no effect on seed dispersers [6]. Indeed, studies have demonstrated that birds are able to cope with fruit SMs whereas rodents are deterred by them [1, 7]. However, this mechanism was only demonstrated at the class level, i.e., between birds and mammals, based on differences in the vanilloid receptors [7]. Here we present experimental and behavioral data demonstrating the use of the broad-range, class-independent "mustard oil bomb" mechanism in Ochradenus baccatus fruits to force a behavioral change at an ecological timescale, converting rodents from seed predators to seed dispersers. This is achieved by a unique compartmentalization of the mustard oil bomb, causing activation of the system only upon seed and pulp coconsumption, encouraging seed dispersal via seed spitting by rodents. Our findings demonstrate the power of SMs to shift the animal-plant relationship from predation to mutualism and provide support for the directed-deterrence hypothesis at the intraspecific level, in addition to the interspecific level.

Original languageEnglish
Pages (from-to)1218-1220
Number of pages3
JournalCurrent Biology
Issue number13
StatePublished - 10 Jul 2012

Bibliographical note

Funding Information:
All experimental protocols were approved by the Committee of Animal Experimentation of the University of Haifa (permit number 096/08). We are grateful to M. Reichelt from the Max Planck Institute for Chemical Ecology for his help in developing the GLS quantification protocol and to the members of the Oranim College animal house staff, particularly N. Dainov, N. Sheena, and N. Keshales, for their help with animal maintenance. We also thank the Israel Nature and Parks Authority, N. Taube, U. Hilberger, L. Samuni, V. Demartsev, A. Weinstein, and especially M. Blank for their help with field work. We are also grateful to L.J. Douglas, T. Keasar, S. Lev-Yadun, K.C. Burns, and an anonymous referee for their useful comments on previous versions of this paper. Support for this study was available through grants from the United States-Israel Binational Science Foundation (2006043), the Israel Science Foundation (189/08), and the Middle East Regional Cooperation Program (TA-MOU-08-M28-013).

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Biochemistry, Genetics and Molecular Biology


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