Aphid addition and exclusion

This summer, Gina Hatch and Abby VanKempen continued a project examining the effects of aphid herbivory on Echinacea angustifolia survival and fitness. This year they found 70 of the original 100 study plants (33 addition and 37 exclusion). Starting July 14th going until August 20th, Abby and Gina visited plants twice each week for a total of 12 visits per plant. On each visit, the plant received its treatment: either adding aphids from other plants if it was in the addition group or removing all aphids if it was in the exclusion group. At the end of the summer, Abby and Gina used the number of leaves with chew marks and holes (signs of foliar herbivory) to quantify herbivory. There was not a significant difference in herbivory between the two treatment groups, where herbivory was measured as the proportion of damaged leaves (p = 0.74). On September 14th and October 15th, Ali Hall took measurements of senescence including number of brown and purple basal and cauline leaves. These have not yet been incorporated into an analysis.

This collection plant had some of the most aphids we've seen yet in one place!

Read more posts about this experiment here.

Start year: 2011

Location: P1

Overlaps with: Phenology and fitness in P1

Products: Fitness measurements were collected during our annual assessment of fitness in P1. A list of focal plants and addition/exclusion datasheets are located in Gina Hatch’s Dropbox folder and can be found here. Gina created a poster and presented at Carleton’s summer research symposium and her poster can be found here. Abby plans to present at the Elbow Lake Library. The senescence data can be found here.



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