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Finding (or Not Finding) Aphids – Aphid Addition/Exclusion Update 2022

Since 2011, Team Echinacea has been studying how the presence (or absence) of the specialist herbivore Aphis echinaceae has an impact on Echinacea fitness. This summer, Kennedy and I (Emma) have been tasked with running the project. Originally, 100 heads were included in the study. This summer, only 41 plants are still present, with 17 addition plants and 24 exclusion plants. At the beginning of the summer, Kennedy and I searched to see if we could find any aphids, regardless of whether the plants were a part of the addition or exclusion treatment. We found exactly none, the same as last year. After consulting with Stuart about the conundrum, we decided to introduce a new population of Aphid echinaeceae into ExPt1, where the project is located. Multiple times a week, Kennedy and I went into prairie remnants, carefully gathered the aphids, then brought them back and placed them onto the living addition plants. Below is a graph of the aphid population growth on these 17 plants, with the red line being the average.

Most of the plants have now received between 70 and 80 Aphid echinaeceae since the 20th of July, with most plants having at least a few living each time we visit the plant. On one plant we even found an ant! Overall, it will still take some work to establish a new population, but we seem to be off to a good start.

2021 Update: Aphid addition and exclusion

Team Echinacea continued the aphid addition and exclusion experiment started in 2011 by Katherine Muller. The original experiment included 100 plants selected from exPt01 which were each assigned to have aphids either added or excluded through multiple years. The intention is to assess the impact of the specialist herbivore Aphis echinaceae on Echinacea fitness.

In 2021, the aphid addition and exclusion project was conducted by Allie Radin with occasional help from other field crew members (often Emma Reineke). They located 26 living exclusion plants and 17 living addition plants. The experiment was conducted from July 9th to July 23rd, with the final visit consisting only of searching for aphids. No aphids were seen or moved in exPt01 this year.

Once again, there were very few aphids (actually, none) in exPt01. This is the second year in a row of missing aphids, raising other questions about where the aphids have gone, let alone their impact on the Echinacea plants. Allie and the team searched the experimental plot thoroughly to make sure no potential aphid hiding spot was left unturned. This included large plants from this year and last year, this year’s flowering plants, and plants which had aphids in previous years. Despite low aphid numbers, other insects such as beetles and thrips were present in the plot.

  • Start year: 2011
  • Location: Experimental Plot 1
  • Overlaps with: Phenology and fitness in P1
  • Data collected: Scanned datasheets are located at ~Dropbox\aphidAddEx\aphids2021
  • Samples collected: NA
  • Products:
    • 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.

2020 update: Aphid addition and exclusion

Team Echinacea continued the aphid addition and exclusion experiment started in 2011 by Katherine Muller. The original experiment included 100 plants selected from exPt01 which were each assigned to have aphids either added or excluded through multiple years. The intention is to assess the impact of the specialist herbivore Aphis echinaceae on Echinacea fitness.

The 2020 aphid team was Anna Allen and Allie Radin. They located 25 living exclusion plants and 16 living addition plants. The experiment was conducted from July 6th to August 19th, with the final visit consisting only of observation. Aphids were moved only during four visits from late July to mid-August due to late arrival and low numbers of aphids. Only one or two aphids were applied to each plant during each visit. They recorded the number of aphids present in classes of 0, 1, 2-10, 11-80, and >80. They also recorded the number of aphids added.

Aphids on an Echinacea leaf

Start year: 2011
Location: Experimental Plot 1
Overlaps with: Phenology and fitness in P1
Data collected: Scanned datasheets are located at ~Dropbox\teamEchinacea2020\allisonRadin\aphidAddEx2020.

Products:

  • 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.

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.

Products:

  • 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.

2018 update: Aphid addition and exclusion

This summer Team Echinacea continued adding and excluding aphids to plants in the experiment that Katherine Muller started in 2011. Katherine Muller randomly designated a sample of 100 Echinacea plants in experimental plot 1 for either aphid addition or removal.

Andy managed the project for the team in 2018, making sure that aphids were removed from the exclusion plants, and added to the addition plants. Twice a week, Andy (and occasionally Morgan) visited every plant in the study, recording the number of aphids, ants, and leaves infested. There remain 54 plants in the aphid study, 26 from the aphid addition plants and 28 from the exclusion plants. The data for this year will be added to the ongoing dataset.

Aphis echinaceae is a specialist aphid that is found only on Echinacea angustifoliaRead more about this experiment.

 

That’s a lot of aphids!

Start year: 2011

Location: Experimental Plot 1

Overlaps with: Phenology and fitness in P1

Data collected: All sheets describing the addition and removal of aphids from echinacea are stored in two places. All physical sheets are in Stuart’s manila folder titled “Aphid Add/Ex 2018.” Additionally, all data from the sheets are present in the aphidAdd2018Master and aphidEx2018Master. The exact path of this file may change but is currently ~\Dropbox\teamEchinacea2018\andyHoyt\aphidAddEx2018\aphidDataAllYears

Physical specimens: We harvested 25 flowering heads from this experiment that will be pulled from the normal ACE processing and pushed through faster. This is so we can more quickly determine achene counts and proportions of full achenes.

Products:

  • 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 previous flog entries mentioning the experiment, on the background page for this experiment.

Aphis echinaceae at Carleton’s Fall Poster Symposium

The aphids were a hit at Carleton’s Summer Research Symposium.

At the Carleton College Summer Research Symposium on October 26th, I presented a poster on my work on the aphid addition/exclusion experiment. Over the summer, I administered the aphid addition and exclusion treatments for the experiment and collected data on leaf senescence and herbivory on plants in the study. Since August, I have been developing an aster model in R to analyze differences in fitness between these two experimental groups. Preparing the aster model for my project was quite a bit of work, but I learned more about R, statistical analysis, and plant-herbivore interactions in the process. Interestingly, Aphis echinaceae has not had an impact on plant fitness over the 8 years of the study.

I am excited to see how the experiment progresses in the coming years, and how the addition of data on seed set affects the results of future fitness models. Quite a few visitors to the symposium were also interested in the results of my analysis and my experience working with the aphids. It was a pleasure to represent the Echinacea Project at Carleton and to have a chance to share the fantastic work the team did over the summer.

A Farewell to Aphids

This morning the much-diminished Team Echinacea (Stuart, Kristen, Lea, Michael, and I) gathered at the Hjelm house to start the day. Lea went to Staffenson Prairie Preserve to measure the flowering phenology of Liatris and Solidago plants. Michael and Kristen began to prepare experimental plot 8 for management in the coming year. The team will treat rogue Ashe trees and collect and broadcast the seeds of several prairie plant species in this plot. This is part of an ongoing effort to ensure that the plant community within the plot is consistent throughout.

Meanwhile, I assessed the leaf damage and senescence of plants in the aphid addition/exclusion experiment in p1. This was the final component of the fieldwork involved in this experiment for the season, and the last step in my independent project before I begin statistical analysis. The next step is to gauge fitness differences between plants in the aphid addition and exclusion treatments by constructing an aster model. While it was exciting to finish this aspect of the project, I will miss spending time with my Aphis echinaceae friends.

Over lunch the team prepared for inclement weather by sharing our experiences of intense weather events. After that, Kristen presented an update on her master’s project. She shared some intriguing preliminary results about the nesting preferences of native ground-nesting bees. We are all looking forward to the results of her study! Due to the rainy weather, the team was ready to call it a day after Kristen’s presentation. We held a short meeting to plan next week’s schedule and then headed home for the weekend.

2017 update: Aphid addition and exclusion

Aphids on an Echinacea leaf

This summer Team Echinacea continued adding and excluding aphids to plants in the experiment that Katherine Muller started. In 2011, Katherine Muller designated a sample of 100 Echinacea plants in experimental plot 1 for aphid addition or removal. The presence or absence of these aphids was maintained by team members once a week in the summer of 2017, for a total of 7 weeks from early July to mid August. We maintained addition on 31 plants and exclusion on 30, for a total of 61 plants. Will Reed set up a data entry system where we could enter data twice from the paper sheets and check for data-entry errors. In early October, Lea Richardson and Tracie Hayes recorded signs of senescence in the leaves of treatment plants. This data can be combined with data from our common garden measuring data to explore the richness of the Echinacea-aphid relationship.

Aphis echinaceae is a specialist aphid that is found only on Echinacea angustifolia. Read more about this experiment.

Start year: 2011

Location: Experimental Plot 1

Overlaps with: Phenology and fitness in P1

Data collected:

  • Aphid counts for each treatment plant on each observation day, on paper
  • Aphid counts recorded in csvs, on the teamEchinacea2017 dropbox
  • Leaf senescence data, recorded on paper
  • Initial and final assessment of aphid counts on treatment plants, recorded on paper
  • Aphid counts also included in p1 measuring data

Products:

  • 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
  • 2015 poster by Daniel Brown and Kyle Silverhus (Lake Forest College) on achene and seed set differences on treatment plants

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.

2016 update: Aphid addition and exclusion

Ants tending Aphis echinaceae

Ants tending Aphis echinaceae

Aphis echinaceae is a specialist aphid that is found only on Echinacea angustifolia. It feeds on sap in Echinacea leaves, and can also be found on flowering heads. This aphid also attracts “ant bodyguards”, which protect the aphids from predation, and in the process may also fend off other potential herbivores. Prior studies by Team Echinacea members have demonstrated that aphid presence does not lead to significant changes in plant fitness in observational studies, although in controlled experiments aphid presence does affect herbivore damage. Furthermore, inbred plants are more susceptible to aphid presence than outbred plants.

In 2011, Katherine Muller designated a sample of 100 plants in experimental plot 1 for aphid addition or removal. The presence or absence of these aphids is maintained by team members two to three times per week. In summer 2016, aphid levels were assessed and maintained 14 times on 70 of these plants (addition on 33, exclusion on 37) from early July until early August. In September, Amy Waananen recorded signs of senescence in the leaves of treatment plants. This data can be combined with data from our common garden measuring data to explore the richness of the Echinacea-aphid relationship.

Start year: 2011

Location: Experimental Plot 1

Overlaps with: Phenology and fitness in P1

Data collected:

  • Aphid counts for each treatment plant on each observation day, on paper
  • Leaf senescence data, recorded on paper
  • Initial and final assessment of aphid counts on treatment plants, recorded on paper
  • Paper records stored in ‘Aphids 2016’ binder, currently at Chicago Botanic Garden
  • Aphid counts also included in p1 measuring data

Products:

  • 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
  • 2015 poster by Daniel Brown and Kyle Silverhus (Lake Forest College) on achene and seed set differences on treatment plants

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.

July 12th: Aphids, Bees, and Roxy

We met a half hour early today so we could do pollinator observations during what we thought would be their peak time. We were wrong. Hardly any bees were out and about on this very windy morning. Everyone finished around 10:30 and we met down in P1 to weed the birdsfoot trefoil.

This little mouse greeted us in G3 this morning.

This little mouse greeted us in G3 this morning.

The lunch table was very crowded today as we had a number of special visitors. Ruth Shaw, Dan (a grad student from U of M), and Amy and Brad Dykstra all came to help out. They also brought yummy chocolates and muffins for a lunch treat.

After lunch, everyone set out different ways. Some people went GPSing and some went to catch pollinators. I got to stay back to teach Lea, Scott, Alyson, and James my special talent, aphid exclusion and addition. Last summer, I worked a lot on the aphid project so it was a lot of fun to do again! Alyson even sang to the aphids to sooth them into their new homes. Roxy saw how much fun we were having and decided to join us for awhile in P1. We found 70/100 original addition/exclusion plants, including 33/50 addition and 37/50 exclusion ones.

Here's some aphids I found on a collection plant in P1.

Here’s some aphids I found on a collection plant in P1.

Team members learning the ways of aphids.

Team members learning the ways of aphids.

Today I also took my first trip to the infamous bog with Alyson and James! Roxy, the bog dog, took me on a wonderful tour of the place. On our way up, we stopped to pet the goats.

Alyson trying to escape the treacherous bog waters.

Alyson trying to escape the treacherous bog waters.

Scape Goat eats out of James's hand.

Scape Goat eats out of James’s hand.