Seed-eating moths had dramatic impacts on plant ecology and evolution
Agriculture, Animals, Appreciation of nature, Asian-American, Brown, Community ecology, Competition, Consumption, Demography, Ecology, Evolution, Experimental, Field, Fundamental research, Grassland, Indirect, Interactions, Lab, Life tables, Natural history, Natural selection, North America, Observational, Plants, Population ecology, Quantitative genetics, Societal Relevance, Terrestrial
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Watch this youtube video to learn more about Anurag and his research!
Agrawal, Anurag A. , Amy P. Hastings, Marc T. J. Johnson, John L. Maron, and Juha-Pekka Salminen. 2012. Insect Herbivores Drive Real-Time Ecological and Evolutionary Change in Plant Populations. Science 338:113-116 PDF
Anurag is an evolutionary ecologist at Cornell Univ., and he studies interactions between species, especially plants and their herbivores, and takes a “community” perspective to address questions about adaptation, trade-offs, plant defense, and general ecological patterns.
PB: Why did you become a biologist?
AA: Deep answer: parents had me outside and in the garden a lot… shallow answer: inspiring college professor
PB: What is your favorite part about your job?
AA: Being outside in nature and thinking deeply about what might be going on out there.
PB: What obstacles have you overcome to get where you are?
AA: lots of rejection; ups and downs.
PB: What advice do you have for aspiring biologists?
AA: Three things: 1) if you know you love something, go for it; 2) work on your confidence and ability to write — these are two most common hang-ups I see in students; and 3) talk to people, find mentors, and figure out the culture of science.
PB: Do you feel that any dimensions of your identity is invisible or under-represented/marginalized in STEM?
AA: In general Asian-Americans are well-represented in STEM, but less so in ecology and evolution. I rarely think of myself as under-represented, but I suppose that I am. Recognizing this has occasionally brought out an important insight.
Take home message of study
Rapid evolution through complex ecological interactions were demonstrated in a field experiment. Insect herbivores had a strong effect on the ecology (demography, competition) and evolution (population genetic structure) of this native plant.
The focal species, evening primrose (O. biennis) is shown on the top left, and one of the main seed-eating moths herbivores (really seed “predators”) is shown on the top right. In plots with insects suppressed, evening primrose did experience less seed predation, and therefore had higher fitness. Nonetheless, a ottom photos, with many more open dandelion –or Taraxicum — flowers open in the insecticide plots). Thus, supprescompetitor of evening primrose, the common dandelion showed a much stronger benefit from insect suppression. Amy Hastings in my lab noticed this (as in the bsing the insects reduced herbivore attack overall, but also changed the competitive dynamics between plants. In response, evening primrose (Oenothera) both evolved less chemical defense against the insects and greater competitive ability in plots with insects suppressed. This dual evolutionary outcome was not caused by a genetic correlation between resistance to insects and tolerance of competitors (but rather appeared to be due to independent selection).
Key Research Points
Experimental suppression of insects in field plots (using an insecticide) favored dandelion (Taraxicum) which competitively suppressed evening primrose (Oenothera) (top panel). In plots with insects suppressed, Oenothera evolved to be less resistant (middle panel, this was due to changes in both chemical defense and flowering phenology). Furthermore, in plots with insects suppressed, Oenothera plants evolved to be more competitive (bottom panel, this evolutionary change was independent of the change in resistance to moths).
Insect pests are major consumers in agriculture and thus understanding their dynamics in nature can help inform pest management strategies. In addition, this native plant-insect system has wonderful natural history which has inspired many biologists and the public.