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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.

Experimental Plot 7 / Hybrid Project Update

Hey flog!

I wanted to make a post detailing my experiment this summer with hybrid Echinacea plants at Hegg Lake. As a student, it was my goal to design, execute, and analyze an experiment with Team Echinacea this summer. Because I’m interested in genetics, I wanted to create something that would connect inheritance with population control among Echinacea. With the help of some seasoned Team Echinacea members (Riley T and Mia S), I was able to construct an experiment that would study the reproduction potential of hybrid Echinacea, crossed between E. angustifolia and E. pallida.

In the history of experimental plot 7, two Echinacea plants have flowered. Most recently, a hybrid Echinacea flowered this spring. This allowed us to cross the hybrid’s pollen with a variety of E. angustifolia and E. pallida in the Hegg Lake area. In order to assess reproduction potential, styles were painted, pollinated, and later observed to look for shriveling. Although styles may shrivel for a variety of reasons, shriveling usually indicates reproduction. In the winter, we will assess the seed-set of these individuals to determine reproductive fitness.

When new species from non-prairie remnants are introduced to new areas, the risk of hybridization among plants of the same genus arises. E. pallida, which has shown to out-compete E. angustifolia in our experimental plots, therefore has the ability to pass on its genes through hybrids. If hybrids are able to reproduce, and continue to pass on E. pallida genes, the risks of genetic swamping increase. Therefore, over time, hybridization could eventually exterminate E. angustifolia from its native prairie.

A picture of me painting bracts for our hybrid crosses. Photo credit to Mia S!

In order to assess reproduction, we hand-crossed a variety of sample pollen with E. angustifolia, E. pallida, and hybrid Echinacea. In this experiment, a shriveled style is a sign of successful reproduction. Because Echinacea plants are not self-compatible, the reasons for a style not to shrivel could vary. Reasons could be that the hybrid was not compatible with this type of Echinacea, or because the specific Echinacea plants were incompatible due to inheritance patterns.

An example of hand-crosses from Shona Sanford-Long, 2012

Our sample size was also effected because only one hybrid Echinacea flowered this summer. In the end, we cross-pollinated our hybrid plant with three E. angustifolia plants, and three E. pallida plants. If more hybrids flower in the future, we will be able to expand our sample size and cross variety. For this reason, we hope to continue this experiment in the following summers if hybrids continue to flower.

Overall, we saw that hybrids were more compatible with E. angustifolia rather than E. pallida. While hybrid reproduction passes on E. pallida genes, a greater chance of reproduction with E. angustifolia keeps native genes (and hopefully, native traits) in the prairie gene pool.

In the future, I will share more updates as we continue to analyze and reassess the data.

Thanks for joining me on this exciting, new experiment!

Anna (Meehan)

2019 Update: Pollen addition and exclusion

Supplemental pollen — pollen that an Echinacea head might not otherwise receive—could increase a plant’s fitness. But does this extra pollination lead to a tradeoff in survival or flowering consistency? Since 2012, we have been manipulating the amount of pollen Echinacea plants receive – either no pollen, or lots of pollen – and recording how this affects their fitness and survival. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. The team bagged the heads of all plants and hand-pollinated the addition treatment, and did not manipulate the exclusion plants further. Plants receive the same treatment across years.

In summer 2018, 14 of the 26 plants alive in the pollen addition and exclusion experiment flowered, producing a total of 25 heads. This year none of those plants flowered. Of the original 38 plants in this experiment, 12 of the exclusion plants and 14 of the pollen addition plants are still alive. No plants died between 2018 and 2019. This year’s data were unique among the eight years of data collected, because not a single plant in the experiment produced even a single head. The dramatic decrease in flowering rates this year may help or hinder us in analyzing this data set and providing answers to this eight-year question.

Tris did not find significant demographic differences between plants which received pollen exclusion, addition or open pollination treatments.

Start year: 2012

Location: exPt1

Physical specimens: We harvested no specimens this year

Data collected: Plants survival and measurements were recorded as part of our annual surveys in P1 and can be found with the rest of the P1 data in the R package EchinaceaLab.

Michael presented a poster on the polLim experiment at MEEC 2019, which you can find here

Tris also presented a poster on polLim at MEEC 2019, which you can find here

You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.

2019 Update: Heritability of fitness – qGen2 and qGen3

Team Echinacea established quantitative genetics experiments to determine the additive genetic variance of fitness in Echinacea, with the idea that we can estimate evolutionary potential of study populations. Quantitative genetics experiments 2 and 3 (qGen2 and qGen3) represent the third generation of Echinacea in our common garden experiments. The grandparents of qGen2 and qGen3 are the 1996 and 1997 gardens. Plants from these experiments were crossed to generate qGen1 (a.k.a. Big Batch), and plants in qGen1 were crossed to produce seed for qGen2 and qGen3, which now inhabit exPt8.

We visit exPt8 every year to assess fitness of Echinacea in the plot. Originally, 12,813 seeds were sown in the common garden. Seeds from the same maternal and paternal plant were sown in meter-long segments between nails. A total of 3253 seedlings were originally found, but only 669 plants were found alive in 2019.

Jay, John, and Avery assess fitness of young Echinacea in exPt8. They’re so tiny (the Echinacea, that is… Jay, John, and Avery are regular sized).

In an exciting turn of events, we found a flowering plant in qGen2 this year! This was the first flowering plant found in exPt8. Fortunately for our one flowering plant, it had four flowering friends to cross with from the Transplant Plot. We took phenology data on the qGen2 head, measured it, and harvested it.

The presence of a flowering plant influenced Riley Thoen to make a new measuring form for exPt8 in 2020. In the past, the exPt8 measuring form was very different from other measuring forms. Through 2019, we measured all leaves of basal plants in exPt8; we only measure the longest basal leaf in other plots. Riley designed the 2020 exPt8 measuring form to mirror the measuring forms from other common gardens. In the future, the exPt8 measure form will have a head subform and team members will only have to measure the longest basal leaf of each plant found.

Start Year: 1996 and 1997 (Grand-dams), 2003 (qGen1 – dams), 2013 and 2015 (qGen2 and qGen3, respectively)

Location: exPt8

Overlaps with: qGen1, 1996 and 1997 gardens, heritability of flowering time, common garden experiment, flowering phenology in experimental plots

Data/material collected: phenology data on the flowering plant and transplant plot plants (available in the exPt1 phenology data frames in the cgData repo), measure data (cgData repo), and harvested heads (data available in hh.2019 in the echinaceaLab package; heads in ACE protocol at CBG).

2019 Update: Inbreeding experiment – Inb2

The inbreeding 2 experiment was planted in exPt1 in 2006 to determine how genetic drift is differentially affecting average fitness of remnant populations. In 2005, team members crossed common garden plants from seven remnant populations. There are three cross types: inbred (crossed to a half-sib; I), within population (randomly chosen; W), and between population (B). Each year, team members assess flowering phenology and fitness of Echinacea in the inb2 common garden.

In 2019, the team searched for Echinacea at 508 positions of the original 1443 positions planted in inb2. In total, we found 351 living plants. Four plants flowered in 2019 but only three produced achenes. Since 2006, 163 Echinacea in inb2 have flowered; they have produced a total of 336 flowering heads.

This winter, Riley Thoen is working on analyzing data and drafting a manuscript for inb2. In these endeavors, he found a small discrepancy in inb2 data: not all plants that were planted in the inb2 plot have a complete pedigree. Therefore, only a subset of the total can be used for analysis. A total of 1136 plants with a complete pedigree were planted in inb2, and of those, 277 were found alive in 2019. All four plants that flowered in 2019 have known pedigrees. A total of 138 plants of known pedigree have flowered and they have produced 284 total heads since the plot was planted in 2006. Surprisingly, within-remnant crosses have the lowest survival of all cross types, at 20%. Inbred crosses have 24% survival and between-remnant crosses have 30% survival. Riley is starting to push data analysis forwards and will certainly post updates on the flog when more discoveries are made!

Summary of survival in inb2 by parental site.

For more summary plots, click these links:

Start Year: 2005 (crosses) and 2006 (planting)

Location: exPt1

Overlaps with: inb1, 1996 and 1997, common garden experiment, flowering phenology in experimental plots

Data/material collected: flowering phenology on the flowering plants (available in the exPt1 phenology data frames in the cgData repo), measure data (cgData repo), and harvested heads (data available in hh.2019 in the echinaceaLab package; heads in ACE protocol at CBG).

Products:

Shaw, R. G., S. Wagenius and C. J. Geyer. 2015. The susceptibility of Echinacea angustifolia to a specialist aphid: eco-evolutionary perspective on genotypic variation and demographic consequences. Journal of Ecology 103: 809-818. PDF

Kittelson, P., S. Wagenius, R. Nielsen, S. Qazi, M. Howe, G. Kiefer, and R. G. Shaw. 2015. Leaf functional traits, herbivory, and genetic diversity in Echinacea: Implications for fragmented populations. Ecology 96: 1877–1886. PDF

2019 Update: Reproductive Fitness in Remnants

Monitoring reproductive fitness in the remnant populations is a staple of Team Echinacea’s summer activities. Understanding the reproductive success of plants in remnant populations provides insight to a vital demographic rate contributing to the persistence (or decline) of remnant populations in fragmented environments.

In summer 2019, we harvested 40 seedheads to study patterns of reproductive fitness in 8 remnant Echinacea populations (ALF, EELR, KJ, NWLF, GC, NGC, SGC, NNWLF) (the same populations used where I studied phenology and gene flow). I randomly selected 1/3 of flowering heads at each remnant to harvest. In addition, I collected all seedheads from especially small or isolated remnants (specifically, GC, KJ, and the cluster of plants just north of EELR).

In early January, I dissected the seedheads. I extracted the achenes by row so that I will be able to observe temporal variation in seed set within heads. Ideally, next I will x-ray the achenes and assess seed set by observing the proportion of achenes that contain embryos. However, the x-ray machine at the Chicago Botanic Garden is currently out of service, so instead I may need to weigh or germinate the achenes to see if viable embryos are inside.

Extracting achenes by row, so that I know which achenes resulted from florets that flowered early (i.e., at the bottom of the seedhead) or late (i.e., at the top of the seedhead). Tedious but possible!

Start year: 1996

Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN

Overlaps with: Phenology in the RemnantsGene Flow in Remnants

Products: We will compile seed set data from 2019 into a dataset with seed set data from previous years, which is located here: http://echinaceaproject.org/datasets/seedset-in-remnants/.

You can read more about reproductive fitness in remnants, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.

2019 Update: Gene Flow in Remnants

In summer 2019, I completed a second season of field work for a study monitoring pollen movement between remnant populations. In summer 2018, I chose two focal areas, the NW sites in the study area (populations: ALF, EELR, KJ, NWLF, GC, SGC, NGC, KJ, NNWLF) and SW sites (populations: LC, NRRX, RRX, YOH, and two large populations in between these sites). This summer, I limited the study to the NW sites. As in 2018, I mapped and collected leaf tissue from all individuals in the study areas and harvested seedheads from a subset of these individuals (see Reproductive Fitness in Remnants). In addition, I monitored the flowering phenology of all of the flowering plants in these populations (see Phenology in the Remnants).

Now, I am working on extracting and genotyping the DNA from the leaf tissue samples and a subset of the seeds I collected. This takes a long time! I will use the microsatellite markers that Jennifer Ison developed in her dissertation to match up the genotypes of the offspring (i.e., the seeds) with their most likely father (i.e., the pollen source). To analyze patterns of gene flow, I will assess how individuals’ location and timing of flowering influence their reproductive success and distance of pollen movement.

In addition, last summer we planted all of the seedlings from 2018 in the experimental plot that John Van Kempen set up at West Central Area High School. We will continue to monitor these seedlings to understand how pollen movement distance (or the distance between parents) influences offspring fitness.

Here is the team after we planted nearly 298 seedlings in the experimental plot at WCA!

Start year: 2018

Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN

Overlaps with: Reproductive Fitness in RemnantsPhenology in the Remnants

Products: I presented a poster based on the locations and flowering phenology of individuals from summer 2018 at the International Pollinator Conference in Davis, CA this summer. The poster is linked here: http://echinaceaproject.org/international-pollinator-conference/.

2019 Update: Flowering Phenology in Remnants

In 2019, we collected data on the timing of flowering for 95 flowering plants (127 flowering heads) in 8 remnant populations, which ranged from 1 to 29 flowering heads. The earliest bloomers (four plants at four different remnants) initiated flowering on July 4. Plant 24050 in the aptly named remnant population North of Northwest of Landfill was the latest bloomer, shedding its last anthers of pollen on August 16. Township mowers had mowed over this plant earlier in the season, which is perhaps why it took longer for it to sprout a new flowering stem. Altogether, the flowering season was 43 days long. Peak flowering was on July 19, when 105 heads were flowering.

This season marked the 19th season of collecting phenology records in remnant populations! Though we do not have data for all populations every year, Stuart monitored phenology in all of our remnant populations in 1996 and in following years (2007, 2009, 2011-2019) students and interns studied phenology in particular populations. From 2014-2016, determining flowering phenology was a major focus of the summer fieldwork, with Team Echinacea tracking phenology in all plants in all of our remnant populations. The motivation behind this study is to understand how timing of flowering affects the mating patterns and fitness of individuals in natural populations.

Flowering occurred much later this season than previous years, with peak flowering falling a full 14 days later in the year than 2018, when flowering started on June 20, and 10 days later than 2017. Of all the years that we data for flowering phenology in the remnant populations in and around Solem Township, this season was the second-latest, with only the 2013 season beginning later, on July 6. However, this observation comes with the caveat that sampling effort varied between years and some years focused on particular contexts, such as population where a portion had experienced a spring burn (see Fire and Flowering at SPP). Many other plants and animals in Minnesota seemed to have delayed phenology this spring and summer, perhaps a result of an unusually wet and snowy spring.

Start year: 1996

Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN

Overlaps with: phenology in experimental plots, demography in the remnants, gene flow in remnants, reproductive fitness in remnants

Data/materials collected: We identify each plant with a numbered tag affixed to the base and give each head a colored twist tie, so that each head has a unique tag/twist-tie combination, or “head ID”, under which we store all phenology data.We monitor the flowering status of all flowering plants in the remnants, visiting at least once every three days (usually every two days) until all heads were done flowering to obtain start and end dates of flowering. We managed the data in the R project ‘aiisummer2019′ and added the records to the database of previous years’ remnant phenology records, which is located here: http://echinaceaproject.org/datasets/remnant-phen/.

A flowering curve (created here using the R package mateable) summarizes the flowering phenology data that we collected in 2019, indicating the number of individuals flowering on a given day and the flowering period for all individuals over the course of the season.

We shot GPS points at all of the plants we monitored. Soon, we will align the locations of plants this year with previously recorded locations and given a unique identifier (‘AKA’). We will link this year’s phenology and survey records via the headID to AKA table.

We harvested a random sample of 1/3 of the flowering heads from each remnants in August and September, plus an X additional heads from populations that were highly isolated, for a total of X harvested seedheads. These are currently stored at the University of Minnesota. This winter, I will assess the relationship between phenology and reproductive fitness by x-raying all of the seeds we collected. In addition, I will determine the paternity (i.e., pollen source) for a sample of seeds by matching the seed genotype to the potential pollen donors. Doing so will shed light on how phenology influences pollen movement and gene flow patterns.

You can find more information about phenology in the remnants and links to previous flog posts regarding this experiment at the background page for the experiment.

Products: I presented a poster based on the locations and flowering phenology of individuals from summer 2018 at the International Pollinator Conference in Davis, CA this summer. The poster is linked here: http://echinaceaproject.org/international-pollinator-conference/.

2019 Update: Dykstra’s Interpopulation Crosses

Small remnant Echinacea populations may suffer from inbreeding depression. To assess whether gene flow (in the form of pollen) from another population could “rescue” these populations from inbreeding depression, we hand pollinated Echinacea from six different prairie remnants with pollen from a large prairie remnant (Staffanson Prairie) and from a relatively small population that we call “Northwest Landfill.” We also performed within-population crosses as a control. Amy Dykstra planted achenes (seeds) that resulted from these crosses in an experimental plot at Hegg Lake WMA.

Plants in the crossing plots were originally found as seedlings like this one

We sowed a total of 15,491 achenes in 2008. 449 of these achenes germinated and emerged as seedlings. Each summer we census the surviving plants and measure them. This summer we found 48 surviving plants. None of these plants has flowered, but we think some of them are close! The largest plant we measured had 4 leaves, the longest of which was 35 cm.

You can read more about the interpopulation crosses, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.

Start year: 2008

Location: Hegg Lake WMA

Data collected: Plant fitness measurements (plant status, number of rosettes, number of leaves, and length of longest leaf), and notes about herbivory. Contact Amy Dykstra to access this data.

Products: Dykstra, A. B. 2013. Seedling recruitment in fragmented populations of Echinacea angustifolia. Ph.D. Dissertation. University of Minnesota. PDF

2019 Update: Echinacea Ploidy

To see how ploidy varies in Echinacea species in our study site, in fall 2019, wecollected and dried tissue from E. pallida, E. angustifolia, and E. purpurea. We also collected tissue from potential hybrids and known hybrids. We brought the dried tissue back to the Chicago Botanic Garden, where we plan to analyze ploidy using a flow cytometer, a device that can be used to find relative genome size.

The flow cytometer used to assess relative genome size. Although it just looks like a box, it is truly a powerful machine.
Example of dried Echinacea tissue… We thought it might be a hybrid when we visited it in the field!

Unfortunately, preparing samples for the flow cytometer is difficult, so we are going to first optimize our Echinacea tissue preparation protocol using live tissue. To do this, we withdrew accessions of E. angustifolia, E. pallida, and E. purpurea from Millennium Seed Bank at the CBG. For E. pallida, we took seed from collections throughout its range to see if its ploidy varies with latitude. We are currently germinating this live tissue to use for ploidy analysis with Elif. We are very excited to see what we find – any finding will help expand genomic knowledge for the genus Echinacea!

Start year: 2019

Location: Hegg Lake WMA, various prairie remnants and restorations, hybrid experimental plots

Overlaps with: Echinacea hybrids (exPt6, exPt7, exPt9), Echinacea pallida flowering phenology

Data/ materials collected: Dried tissue from plants throughout the study area; samples are currently held at Chicago Botanic Garden, in a small box in the glass cupboard to the right upon entering room 159, the Population Biology Lab. Updates will be posted when genome data is available.

Background: If you’d like to learn more about this experiment, check out the background flog post!