their effect on sinigrin glucosinolate. The author found that generalist damage was
negatively correlated with concentration of sinigrin, whereas the specialist herbivore
was positively correlated with increasing sinigrin concentrations. At the same time,
sinigrin concentration was favored when specialists were removed, disfavored when
generalists were removed and selectively neutral when plants were expose to both
generalists and specialist herbivores. When plants are simultaneously exposed to the
attack of herbivores with different degree of specialization, the evolutionary outcome
would depend not only from the strength or direction of selection that each herbivore
can impose but also from the dynamics between them. In the same Brassicacea, B.
nigra, Lankau and Strauss [109] analyzed the effect of inter- and intraspecific competition of two phytophagous species (a generalist folivore mollusk and a specialist aphid)
on sinigrin concentration. They found that only interspecific competition favored the
investment in chemical defense and that this pattern of selection was dependent on the
presence of both specialist and generalist herbivores (diffuse selection). This study
shows that selection acting on chemical traits is highly sensitive to community composition of herbivores (for a review of the impact of ecological heterogeneity on selection
gradients, see [8]). These ecological genetics studies that assess traits mediating plantherbivore interactions have exhibit that selection impose by herbivores play a central
role in shaping chemical phenotypes of plants.
7
Conclusions
Codiversification of vascular plants and arthropod groups is a common outcome of
the antagonistic interaction of host-plants and herbivores mediated by plant chemistry. The reciprocal fitting between host-plants and phytophagous insects that
includes species, traits and genomes draws major adaptive patterns. Either from a
phylogenetic or ecological approach several studies have documented that (1)
secondary metabolites of plants function mainly as defenses to prevent herbivory,
but their reach is constricted of herbivores’ specialization. And, (2) the evolution of
herbivorism is linked to diversification and speciation of plant and insect lineages.
The match of the genetic mechanisms responsible of evolutionary novelty, such as
gen and genome duplications with codiversification and speciation, is the best piece
of evidence of how coadaptation driven by diffuse coevolution over long periods of
evolutionary time is a major source of biodiversity.
Acknowledgments This research is supported by postdoctoral fellowship by the General Directorate for Academic Development Matters (DGAPA, UNAM).
References
1. Abrahamson WG, Blair CP, Eubanks MD, Morehead SA (2003) Sequential radiation of
unrelated organisms: the gall fly Eurosta solidaginis and the tumbling flower beetle
Mordellistena convicta. J Evol Biol 16:781–789
68
E. Kariñho-Betancourt
negatively correlated with concentration of sinigrin, whereas the specialist herbivore
was positively correlated with increasing sinigrin concentrations. At the same time,
sinigrin concentration was favored when specialists were removed, disfavored when
generalists were removed and selectively neutral when plants were expose to both
generalists and specialist herbivores. When plants are simultaneously exposed to the
attack of herbivores with different degree of specialization, the evolutionary outcome
would depend not only from the strength or direction of selection that each herbivore
can impose but also from the dynamics between them. In the same Brassicacea, B.
nigra, Lankau and Strauss [109] analyzed the effect of inter- and intraspecific competition of two phytophagous species (a generalist folivore mollusk and a specialist aphid)
on sinigrin concentration. They found that only interspecific competition favored the
investment in chemical defense and that this pattern of selection was dependent on the
presence of both specialist and generalist herbivores (diffuse selection). This study
shows that selection acting on chemical traits is highly sensitive to community composition of herbivores (for a review of the impact of ecological heterogeneity on selection
gradients, see [8]). These ecological genetics studies that assess traits mediating plantherbivore interactions have exhibit that selection impose by herbivores play a central
role in shaping chemical phenotypes of plants.
7
Conclusions
Codiversification of vascular plants and arthropod groups is a common outcome of
the antagonistic interaction of host-plants and herbivores mediated by plant chemistry. The reciprocal fitting between host-plants and phytophagous insects that
includes species, traits and genomes draws major adaptive patterns. Either from a
phylogenetic or ecological approach several studies have documented that (1)
secondary metabolites of plants function mainly as defenses to prevent herbivory,
but their reach is constricted of herbivores’ specialization. And, (2) the evolution of
herbivorism is linked to diversification and speciation of plant and insect lineages.
The match of the genetic mechanisms responsible of evolutionary novelty, such as
gen and genome duplications with codiversification and speciation, is the best piece
of evidence of how coadaptation driven by diffuse coevolution over long periods of
evolutionary time is a major source of biodiversity.
Acknowledgments This research is supported by postdoctoral fellowship by the General Directorate for Academic Development Matters (DGAPA, UNAM).
References
1. Abrahamson WG, Blair CP, Eubanks MD, Morehead SA (2003) Sequential radiation of
unrelated organisms: the gall fly Eurosta solidaginis and the tumbling flower beetle
Mordellistena convicta. J Evol Biol 16:781–789
68
E. Kariñho-Betancourt