The pollen interference experiment series examines the influence of heterospecific pollen application on the shriveling of Echinacea styles. The shriveling of Echinacea styles has previously been considered a signal of compatible pollen receipt, but shriveling can also occur after the application of pollen from other, closely related species without the creation of a viable seed. The pollen interference project aims to determine which species successfully cause shrinkage of Echinacea styles and whether this interference occurs because of an interspecies match in morphology or interparental genetic compatibility.
During the 2019 summer field season, Julie Bailard performed hand-crosses with pollen isolated from individuals of either Heliopsis helianthoides or Ratibida pinnata on styles of Echinacea angustifolia. The goal of this experiment was to determine if heterospecific pollination of Echinacea with closely-related asters resulted in style shriveling. Pollen from each pollen donor was collected in separate microfuge tubes and applied to Echinacea styles the same day, using a fresh toothpick for each donor. In total, 19 Heliopsis and 8 Ratibida sires were crossed with 16 Echinacea dames for a total of 96 interspecies crosses. In 2009, Allegra Halverson applied pollen from Heliopsis helianthoides,Coreopsis, and Carduusonto Echinacea styles and observed that application of Heliopsis pollen often preceded successful style shriveling.
Data/ materials collected:The data are composed of binary outcomes (y or n) representing either successful style shriveling or style persistence for each pollinated style, recorded 24 and 48 hours after initial heterospecific pollen. Each style’s records are paired with the identity of its maternal plant and the species (application 2009 and 2019) and individual identity code (2019) of the heterospecific pollen donor. Datasheets are found in Julie Bailard’s teamEchinacea2019 Dropbox folder in.
This fall, I had the opportunity to present a poster about my recent field research on pollen interference at the Carleton College Summer Research Symposium on October 19. This poster focused on the parts of my experiment that tested whether false sunflower (Heliopsis helianthoides) pollen interferes with reproduction in Echinacea by causing styles to shrivel. My findings suggested that this style shriveling results from a cooperation between dame and sire identity, such that applying pollen from any one false sunflower might succeed in causing style shriveling on one Echinacea plant but not another. This poster summarizes some interesting and promising early results, and I am looking forward to analyzing the presented data further in the coming months. Thank you to everyone at the Echinacea Project who helped make this experiment possible!
Things have settled down a bit and I’ve started work again on the great pollen challenge! I have ten locations for each of ~150 slides, and for each location I have been recording the count of pollen grains, as well as the number of species as best I can tell (I have also taken notes with descriptions of pollen in each location). My goals at this stage are to get better at recognizing pollen grains of the same species in multiple photos and to get a feel for the diversity and amount of pollen on the pollinators we caught. I’d also like to see if there’s any pollen load size/diversity consistency within a pollinator species.
I have started looking at the male Melissodes sp. and so far it looks like about half of them carry no pollen at all, but some of them have multiple grains at each location.
My question for you is… What makes an insect a ‘pollinator’ in the context of this study? We are focusing on pollinators, and are not including insects that we caught but know are not effective pollinators (ex. syrphid flies), so there needs to be some way to distinguish between other effective and non-effective pollinators. I have thought about making a cutoff like, say, in order for an insect to be a ‘pollinator’ it must have one grain of pollen per location. That way insects that happen to be carrying one grain of pollen (total) but that aren’t really pollinators wouldn’t be counted as pollinators in this study. However, any cutoff seems very arbitrary. It almost seems better to include anything that we know carried pollen, even one grain.
But what about those male Melissodes sp.? If some individuals carry no pollen and others carry quite a bit, do they all count as pollinators, or just the ones that carried pollen?
If you have any ideas, please put them in the comments!
Here is a copy of my excel file with all my data. The sheet labeled corrected data for analysis is the file with all the data for each treatment. The sheet labeled baggins has a list of all the heads I used that need to be harvested, this was also posted in a separate post called “Baggins.” The ones labeled “donor” do not need to be harvested but should not be expected to have high seed set as they were bagged for most of their flowering time.
I need all of the heads used in my project (the ones that are painted) to be harvested in egg cartons (located in the shelf above the sink in the Hjelm house). Please label the compartment of the egg carton with the row, pos and tt color of the head. The egg cartons should be packed so that they wont be disturbed during travel and please be careful with the heads so no seeds fall out! Gretel has a list of all the heads to be harvested and its posted on the flog in July (“Baggins”). Please mail the packaged heads to: 119 School Street, Keene, NH 03431
LANDFILL SPECIES
I have been collecting plants at Landfill this season and have started to compile a list of the plants I have either seen or collected there. If Megan and anyone else would like to add plants to that list that would be great! Or check my identification. This list is very rough at the moment but I will continue to update it as I get more plants identified.
Howdy gang!
Here’s the list of tag ID’s and corresponding letters at the sites used this summer. We flagged different plants on 7/13 and 7/6 and used the same plants for observations on 7/21 and 7/23. For some reason I can’t find the list of flagged plants for 7/13, so it would be great if someone could check on the Hjelm house computer for that info. It may or may not be in the folder for this experiment. I’m sure I compiled that info from the visor memos, but I don’t have the file on my computer. ech flagged plants and tags.doc
We recorded the tag ID’s during FNC so we could go back and check to make sure we had recorded the right number, but we never made the check.
Here’s the file that lists whether the vial had a bee, fly, bfly, or beetle in it: ECH poll obs ALL.xls
Here’s the FNC Data in an excel file: ECH FNC.xls
I hope everything’s going well in MN! It sounds like lots of progress has been made since I left. I thought my poster presentation went pretty well back in Chi-town. The final version of it is in a previous flog post. Thanks again to everyone…I certainly could not have done this without all of your help. I hope the field season ends well. Keep in touch. Oh and here’s an interesting paper I came across recently: brown bj loosestrife comp.pdf
And I really like this picture Daniel took:
And here’s Echinacea taking center stage at CBG:
We pollinated 3 plants in the common garden that were still flowering. Each plant had 3 treatments of stored Echinacea pollen; ambient temperature, frozen, and refrigerated. The frozen and refrigerated pollen caused shriveling, the ambient temperature treatment did not.
Hey All,
Long time no post, I know. Things certainly have been busy around here. As you all probably know, I finished making slides a while back – 372 slides total. WooHoo!!
Now, onto the next step, taking pictures of these slides. I took my very first pictures today, just a couple to get the hang of things, they are attached to this post. From my fiddling around today, I can see that this is going to be a lot more work than I thought. First off, the pollen is hard to find, it’s not all at the same level of view, some of them are on top of the stigma and then they’re really hard to see. Also, it’s challenging to focus in enough to where I can ID pollen grains. Stuart suggested working on a random sample of my slides for the rest of the summer, and completing them this fall at the CBG. The only issue there is the change of machinery, but hopefully we can figure something out.
As for the rest, I think I’ll be taking 1-2 shots of the entire style, and labeling them thus: stylevialID_site_date/time_A# – so A1, A2, etc. Then I’ll zoom in and proceed to take pictures at sites B through F on the style, and for each change in focus will be another number. The question is whether I should attempt to get a good sense of the exact number of pollen grains on the stigmas or try to ID the pollen types. I’d like to be able to do both, but I think for this summer at least, I’ll try to get a handle on the former rather than deal with the later.
On that note, Caroline suggested using a clicker to count the number of pollen in a picture, and that seems like an excellent suggestion. Does anyone know if we’ve got one?
I made new columns in the .csv spreadsheet for the factors and levels we discussed. I will work on a list of hypotheses to test. I think I changed the definition of “y” when I did my 24 hour analysis. Can I give “y” a different name for each analysis? Or does the code need to read a defined “y” each time?
Thanks for the help and check out the graph of 24 hours and the summary m2.
Here are the data on the three pollen types and the protocol for measuring.
I used the same plant/pollen from each plant and measured at least 30 different pollen grains from each. I didn’t use any pollen if its pole faced forward – only if it was sideways.
Bad news – the Ech. ang. and Heli. heli. are very close. Good news – maybe the pollinators and plants can’t tell them apart either.
