2019 update: Aphid addition and exclusion

In summer 2019 Team Echinacea continued the aphid addition and exclusion experiment begun in 2011 by Katherine Muller. The original experiment included 100 plants selected from experimental plot one to have aphids added and excluded through multiple years. The intention was to assess the impact of specialist herbivore Aphis echinaceae on Echinacea fitness.

This year Erin and Shea managed the project. They located 15 living addition plants and 22 exclusion plants. The experiment was conducted from July 8th to August 16th. Erin and Shea performed addition and exclusion twice a week for a total of 10 events, with the final visit consisting only of observation. The number of aphids applied to each plant depended on how many could be obtained and varied between five and 10. They recorded the number of aphids present in classes of 0, 1, 2-10, 11-80 and 80<. They also recorded the precise number of aphids added. Erin and Shea found that natural hair paintbrushes were more effective than synthetic and trimmed the brushes down so fewer than half the hairs remained.

Aphids were gently pushed into petri dishes using paintbrushes

Start year: 2011

Location: Experimental Plot 1

Overlaps with: Phenology and fitness in P1

Data collected: Scanned datasheets are located at ~Dropbox\teamEchinacea2019\aphidAddEx2019\aphidAdEx2019Datasheets.pdf. The paper sheets are located in the CBG common area filing cabinets in a manilia folder labeled “Aphid ad/ex 2019,” located next to the 2018 aphid folder.


  • Andy Hoyt’s poster presented at the Fall 2018 Research Symposium at Carleton College.
  • 2016 paper by Katherine Muller and Stuart on aphids and foliar herbivory damage on Echinacea
  • 2015 paper by Ruth Shaw and Stuart on fitness and demographic consequences of aphid loads

You can read more about the aphid addition and exclusion experiment, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.


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