Natural GMOs Part 188. Red Queen Redux. Jungle Chemical Warfare Battle for Survival May Yield the Rain Forest’s Diversity

Image, Tenial, Copyright expired.

Carl Zimmer explains the jungle chemical warfare story:

...Plants are not helpless victims, however. They have evolved a staggering variety of defenses. Some grow cups of nectar on their leaves to attract sugar-hungry ants, which also attack insects feeding on the leaves. Some plants defend themselves by sprouting hairs. “To us they seem soft and fuzzy,” Dr. Coley said, “but to a small caterpillar with a soft belly, they can be more like meat hooks.”
The most impressive defenses in tropical plants are invisible, however. A plant may pack each of its leaves with hundreds of kinds of insect poisons. Those toxins can make up half the dry weight of a tropical plant leaf.
As farmers know all too well, insects can evolve resistance to pesticides. A similar evolution plays out in tropical forests, where insects can disarm many of the chemicals that plants use against them.
Of course, plants in temperate regions face attacks from insects, too. But Dr. Coley and Dr. Kursar argue that those plants are more adapted to the bigger threats they face, from the bitter cold of winter and other environmental challenges. In the tropics, plants enjoy a balmy climate year-round. While the physical environment poses less of a threat to tropical plants, it makes insects a bigger danger. They can grow faster in the warm, moist climate; without killing frosts, they can produce more generations each year.
The tropics have thus become host to an arms race. Each species of plant is evolving defenses against its enemies, which evolve counterdefenses in turn. This arms race would explain why tropical plants have become so loaded with toxic compounds...

More @ Battle for Survival May Yield the Rain Forest’s Diversity - NYTimes.com:

About On Tropical Forests and Their Pests
Phyllis D. Coley, Thomas A. Kursar
Science 3 January 2014: Vol. 343 no. 6166 pp. 35-36 DOI: 10.1126/science.1248110

Key Quote

"Evidence from several lineages of tropical trees and shrubs shows that closely related species have diverged in defenses while differing little in nondefense traits (9–12). This supports the Red Queen hypothesis (13), which states that antagonistic interactions between hosts and their pests lead to natural selection for beneficial adaptations and counter-adaptations in both groups. Because herbivores are continually evolving counter-adaptations to plant defenses, plant defensive traits should evolve faster than adaptations to a more static abiotic environment."

References and Notes

1. S. J. Wright, Oecologia 130, 1 (2002).
2. C. Baralotoet al., J. Ecol. 100, 690 (2012).
3. D. T. Palowet al., Funct. Ecol. 26, 1144 (2012).
4. B. E. Sedioet al., J. Ecol. 100, 1183 (2012).
5. X. Liuet al., Funct. Ecol. 27, 264 (2013).
6. E. G. Leighet al., Biotropica 36, 447 (2004).
7. D. W. Schemskeet al., Annu. Rev. Ecol. Evol. Syst. 40, 245 (2009).
8. J. X. Becerra, Proc. Natl. Acad. Sci. U.S.A. 104, 7483 (2007). The impact of herbivore–plant coevolution on plant community structure
9. T. A. Kursaret al., Proc. Natl. Acad. Sci. U.S.A. 106, 18073 (2009). The evolution of antiherbivore defenses and their contribution to species coexistence in the tropical tree genus Inga
10. B. E. Sedio, thesis, University of Michigan (2013)
11.  J. X. Becerra, K. Noge, D. L. Venable, Proc. Natl. Acad. Sci. U.S.A. 106, 18062 (2009). Macroevolutionary chemical escalation in an ancient plant–herbivore arms race
12. P. V. A. Fineet al., Ecology 94, 1764 (2013).
13. L. Van Valen, Evol. Theory 1, 1 (1973).
14. M. R. Servedioet al., Trends Ecol. Evol. 26, 389 (2011).

See also previous GMO Pundit posts: 

• Natural GMOs Part 19. The Evolutionary Arms Race.
• Natural GMOs Part 20. The Red Queen. 
• Natural GMOs Part 170. The Red Queen was right: We have to run to keep in place