Abstract
The evolution of warning coloration (aposematism) has been difficult to explain because rare conspicuous mutants should suffer a higher cost of discovery by predators relative to the cryptic majority, while at frequencies too low to facilitate predator aversion learning. Traditional models for the evolution of aposematism have assumed conspicuous prey phenotypes to be genetically determined and constitutive. By contrast, we have recently come to understand that warning coloration can be environmentally determined and mediated by local prey density, thereby reducing the initial costs of conspicuousness. The expression of density-dependent colour polyphenism is widespread among the insects and may provide an alternative pathway for the evolution of constitutive aposematic phenotypes in unpalatable prey by providing a protected intermediate stage. If density-dependent aposematism can function as an adaptive intermediate stage for the evolution of constitutive aposematic phenotypes, differential reaction norm evolution is predicted among related palatable and unpalatable prey populations. Here, I present empirical evidence that indicates that (i) the expression of density-dependent colour polyphenism has differentially evolved between palatable and unpalatable populations of the grasshopper Schistocerca emarginata (= lineata) (Orthoptera: Acrididae), and (ii) variation in plasticity between these populations is commensurate with the expected costs of conspicuousness.
Full Text
The Full Text of this article is available as a PDF (267.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Applebaum S. W., Heifetz Y. Density-dependent physiological phase in insects. Annu Rev Entomol. 1999;44:317–341. doi: 10.1146/annurev.ento.44.1.317. [DOI] [PubMed] [Google Scholar]
- Barnes A. I., Siva-Jothy M. T. Density-dependent prophylaxis in the mealworm beetle Tenebrio molitor L. (Coleoptera: Tenebrionidae): cuticular melanization is an indicator of investment in immunity. Proc Biol Sci. 2000 Jan 22;267(1439):177–182. doi: 10.1098/rspb.2000.0984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brodie E. D., 3rd, Agrawal A. F. Maternal effects and the evolution of aposematic signals. Proc Natl Acad Sci U S A. 2001 Jun 19;98(14):7884–7887. doi: 10.1073/pnas.141075998. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dopman Erik B., Sword Gregory A., Hillis David M. The importance of the ontogenetic niche in resource-associated divergence: evidence from a generalist grasshopper. Evolution. 2002 Apr;56(4):731–740. doi: 10.1111/j.0014-3820.2002.tb01384.x. [DOI] [PubMed] [Google Scholar]
- Hoffmann AA, Merilä J. Heritable variation and evolution under favourable and unfavourable conditions. Trends Ecol Evol. 1999 Mar;14(3):96–101. doi: 10.1016/s0169-5347(99)01595-5. [DOI] [PubMed] [Google Scholar]
- Lindström L., Alatalo R. V., Lyytinen A., Mappes J. Strong antiapostatic selection against novel rare aposematic prey. Proc Natl Acad Sci U S A. 2001 Jul 17;98(16):9181–9184. doi: 10.1073/pnas.161071598. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mccaffery A, Simpson S, m A gregarizing factor present in the egg pod foam of the desert locust Schistocerca gregaria. J Exp Biol. 1998;201(3):347–363. doi: 10.1242/jeb.201.3.347. [DOI] [PubMed] [Google Scholar]
- doi: 10.1098/rspb.1997.0081. [DOI] [PMC free article] [Google Scholar]
- doi: 10.1098/rspb.1998.0503. [DOI] [PMC free article] [Google Scholar]
- Pener M. P., Yerushalmi Yoram. The physiology of locust phase polymorphism: an update. J Insect Physiol. 1998 May;44(5-6):365–377. doi: 10.1016/s0022-1910(97)00169-8. [DOI] [PubMed] [Google Scholar]
- Riipi M., Alatalo R. V., Lindström L., Mappes J. Multiple benefits of gregariousness cover detectability costs in aposematic aggregations. Nature. 2001 Oct 4;413(6855):512–514. doi: 10.1038/35097061. [DOI] [PubMed] [Google Scholar]
- Servedio M. R. The effects of predator learning, forgetting, and recognition errors on the evolution of warning coloration. Evolution. 2000 Jun;54(3):751–763. doi: 10.1111/j.0014-3820.2000.tb00077.x. [DOI] [PubMed] [Google Scholar]
- Simpson S. J., Despland E., Hägele B. F., Dodgson T. Gregarious behavior in desert locusts is evoked by touching their back legs. Proc Natl Acad Sci U S A. 2001 Mar 27;98(7):3895–3897. doi: 10.1073/pnas.071527998. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Speed Michael P. Can receiver psychology explain the evolution of aposematism? Anim Behav. 2001 Jan;61(1):205–216. doi: 10.1006/anbe.2000.1558. [DOI] [PubMed] [Google Scholar]
- Sword G. A., Simpson S. J., El Hadi O. T., Wilps H. Density-dependent aposematism in the desert locust. Proc Biol Sci. 2000 Jan 7;267(1438):63–68. doi: 10.1098/rspb.2000.0967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tardieu C. Ontogeny and phylogeny of femoro-tibial characters in humans and hominid fossils: functional influence and genetic determinism. Am J Phys Anthropol. 1999 Nov;110(3):365–377. doi: 10.1002/(SICI)1096-8644(199911)110:3<365::AID-AJPA8>3.0.CO;2-T. [DOI] [PubMed] [Google Scholar]
- WADDINGTON C. H. Genetic assimilation. Adv Genet. 1961;10:257–293. doi: 10.1016/s0065-2660(08)60119-4. [DOI] [PubMed] [Google Scholar]