Seed Addition 2022: Seed Predators?

While the volunteers and I cleaned heads for the seed addition experiment, we encountered something we don’t see every day: seed predators in Echinacea

Busted! This seed predator was still alive and chowing down on Echinacea when I found it. Noticed the holes it gouged in the achenes.
The seed predators seemed to produce a thin, sticky filament that would cause achenes and chaff to attach to each other.

The heads we were cleaning were from two sites we don’t typically harvest from, Hutchings and Nice Island. We had 155 heads from each site, stored all together in three gBags, 1 for hutchings and 2 for nice island. The heads were not in individual hBags. This storage method may have made it easier for the predators to move from head to head, but it’s unclear if they were able to cross from one gBag to another.

Hutchings was the most impacted; I would estimate nearly 50% of achenes from the site had been predated. Seed predation was less common, but still present, among the achenes from nice island, with roughly 1/10 achenes being affected. I removed at least 20, most alive, a few dead, from the hutchings heads during the cleaning and enrichment processes, and maybe 5 from the nice island batched

The grubs ranged from roughly 2-5mm long, and were a peachy orange color with a dark and hard head. They resembled the seed predators we’ve observed in Liatris aspera. I removed all the seed predators I encountered from the Echinacea and isolated them in a paper bag (the Grub Hub) to prevent further damage to the achenes.

Liatris Update

Good news on the Liatris front: all hands-on work, from harvesting to x-raying, is complete! The process began in the summer of 2021 and involved lots of help from the field crew, wise, long-term Team Echinacea members, eager and efficient short-term members, and everyone in between.

Mia V and I were also able to complete data entry and data cleaning today, paving the road forward for analysis.

Now that we’re moving on to computer work, we came up with some primary questions to pursue (and some hypotheses):

  • Is there a significant difference in seed predation rates between burned and unburned and unburned remnants?
    • We suspect that predation will be higher in burned remnants because density of plants will be higher
  • Is there a correlation between seed predation rates and plant density?
    • We hypothesize that higher density will be correlated with higher rates of predation
    • We will use nearest neighbor as our measure of density
  • Is there a correlation between individual plant size and predation rates?
    • We hypothesize that larger plants will receive higher rates of predation
    • We will use number of flowering heads as our measure of plant size.

I’m now in the process of making plots to help us visualize the data we’ve collected, and soon we can begin to seek answers for our questions.

Because none of our questions at the moment directly relate to pollination, we don’t need to quantify seed set, which is the “classify” step. Using the x-rays to count how many achenes contain seeds is our method of determining pollination rates (seed = pollinated, no seed = not pollinated). This step will likely stay low priority for awhile, so don’t fret about the empty bar. All part of the plan.


Liatris Update

Liatris aspera 2021 progress in the lab is steadily marching on. Thanks to the work of the Carleton externs last winter, we began Northwestern’s spring quarter essentially halfway done (only needing to do some brief back-peddling due to a change in protocol).

With the help of work study Mia V., cleaning, the process of removing the achenes from the flowering heads and gather data on achene-per-head count, is completely finished. Mia has also made excellent progress on randomizing, the step where we select a random sample of achenes to be x-rayed as well as quantify seed predation. We’re on track to finish randomizing later this week or next. Following that, we can x-ray the final batch of 56 liatris, allowing us to quantify seed set, and all the hands-on work for our 234 liatris from 2021 will be complete!

Priorities going forward:

  • Finish randomizing and x-raying for batch D
  • Complete randomization data entry and verification
  • Develop methods of data analysis to compare
    • Burned vs. unburned predation rates
      • In regards to density
      • In regards to number of heads per plant
  • Develop methods of classifying seed set from x-rays (low priority)

2021 Update: Task efficiency evaluation

All of our summer research involves plenty of labor, with different projects requiring their own and sometimes overlapping fieldwork. This year, we devised a way of monitoring and quantifying the time spent on that labor using Excel. Designed by Wesley and primarily contributed to by Wesley and later Alex, the task efficiency evaluation kept track of time spent by 18 individuals devoted to 54 unique tasks. For example, Team Echinacea spent a total of 29,045 minutes (484 person-hours) recording the phenology of flowering plants and 4295 minutes (72 person-hours) measuring plants in experimental plot 8. The project ran from 15 Jun to 8 Oct, 2021.

  • Start year: 2021
  • Location: Followed all tasks we did in and around Solem Township
  • Overlaps with: Everything!
  • Data collected: Amount of time spent on tasks per individual. All data can be found at Dropbox/teamEchinacea2021/wyattMosiman/taskEfficiencyEvaluation
  • Products: Spreadsheet identifying how long certain projects took in terms of person hours.

2021 Update: Liatris fire and flowering

As a part of our research looking into the role fire plays on plant reproduction and population dynamics, we collected geospatial and flowering data on Liatris aspera at 22 prairie remnants in and near Solem Township, MN. Six of these remnants burned in spring of 2021. During the growing season, we collected data on the position, inflorescence count, and number of flowering heads for over 2400 individuals (exact number is unknown still because some individuals were shot twice with the GPS due to calibration errors).

We also randomly selected 234 Liatris as focal plants, which we harvested once they had gone to seed and brought back to the lab for cleaning. We hope to be able to use the inflorescences we collected to quantify seed set and compare density effects between burned and unburned remnants.

Over the summer, Team Echinacea spent 5955 minutes (99 person-hours) shooting Liatris GPS points and 2235 minutes (37 person-hours) harvesting the focal Liatris plants.

  • Start year: 2021
  • Location: 22 prairie remnant sites in and around Solem Township, MN
  • Overlaps with: Liatris insects on flowering heads
  • Data collected: All data related to this experiment can be found at ~Dropbox/burnRems/remLiatris
  • Samples or specimens collected: We harvested inflorescences from 234 individuals to be cleaned in the lab.
  • Products: Stay tuned!

2021 Update: Liatris arthropods on heads

For Wesley’s individual project, we made pollinator visitation observations and noted the presence or absence of other arthropods on Liatris aspera heads. Using the focal plants from the Liatris fire and flowering study, we were able to perform 95 5-minute observation periods on 84 individual plants. Most visitor identifications were made by eye in the field; however, we captured one bumblebee (released upon identification) and one fly (captured and frozen for future identification). We also recorded presence/absence data for Pennsylvania leatherwings, ants, ambush bugs, spiders, and other beetles.

All focal plants from the Liatris fire and flowering study were brought back to the lab, where the arthropod experiment is continuing via the quantification of seed predation. We have also encountered living larvae throughout the Liatris cleaning process which we hope to identify, possibly through rearing.

  • Start year: 2021
  • Location: 22 prairie remnant sites in and around Solem Township, MN
  • Overlaps with: Liatris fire and flowering
  • Data collected: Scanned datasheets and their typed versions can be found in ~Dropbox/remLiatris/liatrisObservations
  • Samples or specimens collected: 1 fly was captured for identification. Additionally, 234 focal plants were harvested. These plants are currently being cleaned and processed in the lab.
  • Products: Wesley’s REU was based on this project, which may at some point result in a paper or poster. Stay tuned!

Seed Addition Experiment: Achene Selection Process

For the seed addition experiment, we used achenes from p2 in 2016, which were selected for the batch’s particularly high seed set. The achenes were originally in 160 envelopes sorted by flowering head so that we knew which maternal plants were contributing to the experiment. The envelopes were selected mostly randomly, though some that appeared upon visual inspection to have non-viable achenes were excluded to ensure maximum viability in the achenes used for the experiment.

We combined the achenes from all 160 envelopes into one pile in order to make a homogenized mixture. Using a column blower set to 5/8″, we segregated the “rich” achenes (containing a seed) from the “thin” achenes (seedless). Achenes were considered rich if their mass was above 2 mg. We measured a sample of achenes from the final rich batch to ensure exclusion of thin achenes, finding that only about 1/30 achenes was <2 mg, and acceptable margin of error.

This collection of isolated rich achenes would became our source of seeds for the seed addition experiment. In order to divide achenes equally for use along different transects, we counted by hand achenes from the rich pile and placed them into envelopes, with each envelope containing 50 achenes. During this process, we removed achenes that appeared to be visually severely damaged to ensure that only viable achenes will be used for the experiment.

The end result of the achene selection process was 250 envelopes each containing 50 achenes, all of which were taken from a homogenized mixture of achenes whose maternal plants flowered in p2 in 2016.

Summer was fun and fall will be too!

Wesley here,

I had a blast being a part of Team Echinacea this summer. In my 14 weeks with the project, I spent my days in beautiful prairies, gained lots of sciency skills, made many friends (both people and plants) and enemies (mainly ground squirrels), and overall had a lovely experience.

This flog post is to reminisce about all the fun I had this summer and to commemorate the fact that I will be staying on the team through the fall and for the foreseeable future! Because the Chicago Botanic Garden is so close to Northwestern, I’m able to travel there by bus to work in the lab. Better yet, Stuart was able to set up the position so that I would be able to receive work study funding from the school.

Here’s to an echinacea-filled autumn!

Exciting day

Today was indisputably exciting for all parties at the Echinacea Project and even the DNR.

First off, check the sunrise. Nice and foggy. Neat.

We woke around 6:30 this morning to make a cake to celebrate the 25th birthdays of the echinacea Stuart planted in 1996. We ended up making two cakes because the first one didn’t turn out exactly as anticipated (apparently accidentally substituting ingredients can cause problems) but the second ended up lovely.

We packed the good cake—the other we’ll eat later with copious quantities of ice cream to mask the questionable taste and texture—along with the noodles we made last night and headed to work.

Alex and I spent most of the work day playing with the GPS units, but I think Collins was feeling kind of cranky today because her case shut on both of my pinky fingers on separate occasions.

After work, we stayed at Hjelm because conditions were finally right to have a bonfire and get rid of some wood piles that had been accumulating. This bonfire also doubled as the birthday party for the ’96 plants.

The bonfire had calmed down by around 8pm, when we packed it up and called it a day. The coals need to be cold to the touch tomorrow at 8am to be in line with regulations, so if the pile is still in any way “on fire,” it’ll be getting a dousing with a hose.

Huzzah, Wesley

Back at it

After last week’s sweltering hot temperatures and absolutely atrocious air quality, Team Echinacea is finally back in the field at full force (minus Alex, we miss you!)

My morning consisted of a quick phenology trip to the few sites left on our Northwest loop. We needed to make the hike out to landfill for the six plants still flowering, but it meant I got to see a plenty of fun butterflies flitting about, and certainly plenty of monarchs. I seem to be seeing more and more of them recently.

After lunch we spent most of the afternoon measuring P2. With 40 rows left, we were hopeful that we’d be able to finish, and let me tell you, we came tantalizingly close. We had to pack up and head back around 4:30 to make sure we finished work on time, but it was truly and agonizing experience to leave just four and a half rows for the next day.

Bonus pic for Monday is whatever these little dudes are. What are they doing on this echinacea leaf? Can you name them? I sure can’t.

Huzzah! -Wesley