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Evolution of plant-herbivore relationships

Evolution of plant-herbivore relationships. Photo G. Weiblen. Evolution of insect-plant associations: by descent or colonization. plant. insect. Association by descent. Association by colonisation. Sequential evolution :

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Evolution of plant-herbivore relationships

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  1. Evolution of plant-herbivore relationships Photo G. Weiblen

  2. Evolution of insect-plant associations: by descent or colonization plant insect Association by descent Association by colonisation Sequential evolution: the evolution of herbivorous insects follows the evolution of plants while the plant evolution is not affected by herbivores. Coevolution: the evolution of plant lineages influences the evolution of herbivore lineages and vice versa

  3. How the fig - wasp relationships evolved?

  4. Coevolution: reciprocal evolutionary change in interacting species Escape-and-radiate coevolution 1. Plants evolve by chance (via mutation, recombination) a new toxin/deterrent. 2. New chemical leads to protection from herbivores. 3. Protected plants enter a new adaptive zone, in which they are free to radiate. 4. Herbivores evolve (via mutation, recombination) ways to deal with new toxin. 5. Herbivores enter a new adaptive zone and are free to radiate. 6. The cycle is repeated.

  5. Escape and radiation concept: plants develop new defence [yellow, orange], their speciation rate increases, herbivores develop counter-defence and colonize them Futuyma & Agrawal, 2009, PNAS 106: 18054–18061

  6. Gall wasps (Cynipidae): second largest radiation of gallers, 1300 spp. Most of species on woody plants, particularly oaks (a), species on herbaceous plants mostly on Asteraceae (b) Phylogenetic conservatism in the position of galls on host plants

  7. Cynipid gallers Andricus on oaks in Europe: evolutionary conservatism in gall type

  8. inquilines do not induce their own galls, feed inside galls of other spp. Host plants of gallers

  9. Phyllobrotica beetles and Scutellaria hosts: parallel (or sequential?) evolution S. galericulata P. quadrimaculata Farrell & Mittter 1990

  10. Tetraopes beetles and Asclepias hosts: an example of escape-and-radiate coevolution? Farrell & Mitter 1998

  11. Blepharida beetles on Bursera plants: secondary chemistry explains multiple host colonizations different secondary chemistry marked by different colour Host selection by beetles can be better explained by plant similarity in secondary metabolites than by plant phylogeny Bursera phylogeny Bursera phylogeny does not correspond with phylogeny of its beetles Becerra 1997

  12. Asclepias defense strategies: life history traits and phylogeny A. californica A. exaltata A. asperula Phenogram recognizing three defense strategies based on 7 traits: Distribution of defense strategies on Asclepias phylogeny A: soft leaves, many trichomes, high latex B: tough leaves, low water content, medium latex C: soft leaves, low latex, high cardenolides Agrawal & Fishbein, Ecology, 87 Suppl., 2006, S132–S149

  13. Asclepias defense strategies: phylogenetically unstable Agrawal & Fishbein, Ecology, 87 Suppl., 2006, S132–S149

  14. Phylogenetic and physiological response may not be necessarily the same Asclepias syriaca • Latex and trichomes: • no correlation within species (Asclepias syriaca) • a positive correlation across 24 species of Asclepias Agrawal and Fishbein 2006

  15. Herbivores feeding on latex-rich Asclepiadaceae - Apocynaceae colonize preferably other latex plant lineages Number of colonization of plants from various orders by herbivores feeding on latex-rich Asclepiadaceae - Apocynaceae plants: insects retain their taste for latex

  16. Many herbivore lineages retain broad preferences for certain plant lineages

  17. Where to find genuine plant - insect coevolution? • The plant - insect mutualisms where • the insect pollinates flowers • then oviposits to some of them so that the larval survival depends on successful pollination Ficus - Agaonidae wasps Yucca - Tegeticula moths (Yponomeutidae) Trollius - Chiastocheta (Anthomyiidae) flies Glochidium - Epicephala (Gracillariidae) moths

  18. male female Fig inflorescence: flowers are hidden inside

  19. Ceratosolen wasps: Oviposition to fig flowers through stylus

  20. Yucca plants - Tegeticulamoths

  21. Epicephala sp. (Gracillariidae) and Glochidium (Euphorbiaceae) Kato et al. 2003. PNAS 100:5264

  22. Is narrow host specialization an evolutionary dead-end? Specialized Chrysomela beetles dependent for anti-predator defence on metabolites from their hosts develop a new chemical defense butyric acids salicylaldehyde from salicin monoterpene iridoids Termonia et al. 2001

  23. Mass extinction (Cretaceous-Tertiary boundary): specialists die first Labandeira et al. 2002 PNAS 99:2061

  24. angiosperms conifers Cycadales 1 - 5: colonizations of angiosperms Beetles: high species diversity associated with feeding on angiosperms Farrell 1998

  25. Host specificity: is narrow specialization determined by speciation dynamics? Transition from a generalist to a specialist is more likely than reverse transition Nosil 2002

  26. No. of mouthpart classes No. of insect families While number of insect families is steadily increasing through evolution, there has not been any major inovation in mouthparts dor almost 100 million years: has everything been already invented?

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