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2016 update: Mating compatibility in remnants

In 2016, we continued our ongoing study of mating compatibility in the remnants that began in 2014. This experiment is designed to assess population level compatibility and to investigate whether the difference in the timing of flowering (phenology) and the distance between plants predict whether mating will be successful, or the cross will be compatible. This year, we randomly selected 10 focal plants from remnant populations and chose their four nearest neighbors to be pollen donors.

We conducted this study in six remnant populations with approximately ten focal plants at each for a total of 279 pairwise crosses. Occasionally we were unable to collect pollen from the four nearest neighbors of the focal plant because they flowered asynchronously with the focal plant, and in those cases we chose the nest nearest individual available. Excluding all other pollinators, we performed hand-crosses between the focal plants and their pollen donors and assessed style persistence the following day to evaluate the compatibility of each cross.

We observed wide variation in compatibility among sites, with focal plants at some sites compatible with an average of 90% of their nearby neighbors and only 64% at others. Further analysis will tell what relationship this pattern might have with individuals’ synchrony of flowering and proximity to mates!

We exclude pollinators from our focal plants and pollen donors using bridal veil material, an evocative method rich with symbolism of purity and loss of innocence.

Start year: 2014

Location: large remnant populations in Solem Township, Minnesota

Data collected: We collected data about the identities of the individuals and outcome of crosses on paper datasheets. The phenology data was collected electronically. We used GPS units to collect spatial data about individuals’ location and isolation.

Products: We entered the data from 2016 and it is ready to be compiled and analyzed with the 2014 and 2015 datasets.

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

7/18/2015: Saturday and compatibility project update

 

Can you guess who it is?

Ben Lee (2015); ballpoint pen on notebook paper

It was a good Saturday of phenology and fun for Team Echinacea! A group of us braved the morning fog and went out to our remnant sites to assess phenology. Lots of plants have reached or are nearing the end of their flowering time already. Later in the day we went swimming, played bananagrams, and drew blind contour drawings of each other.

This weekend, Danny and I have been working the ongoing project assessing compatibility between Echinacea individuals within remnants. On Friday, we went to Loeffler’s Corner and randomly selected 10 flowering plants; these are our focal plants. We do four crosses on each focal plant, with pollen from each of the crosses being placed on four or 5 bracts of the focal plants. We can tell if the cross is compatible by seeing if the styles shrivel after receiving pollen; if they do, they’re compatible, but if the styles persist, then the cross was between two plants that are not compatible.

For this study, we cross each focal plant with its nearest flowering neighbor, its furthest flowering neighbor, a plant that flowered early (i.e. one that is just ending flowering), and a plant that flowered late (i.e. one that just started flowering). To keep track of the crosses, we paint the bracts of the focal plant different colors which correspond to the cross that the style will receive: near, far, early, or late. We paint bracts corresponding to male florets; the next day, they will be styles, and we will be able to do the crosses. After we paint, we cover each focal flower with a pollinator exclusion bag so that we can be sure that no other pollen is introduced.

On the next day, Saturday, the styles of our focal plants emerged. We collected pollen from the various pollen donors and used a toothpick to perform the crosses, carefully placing pollen onto the styles identified by their painted bracts. We cover the focal flowers back up with the pollinator exclusion bags and wait one day to see if the styles shrivel.

This morning, Danny and I went back out to Loeffler’s to check on style shriveling. Here are the results!

  Compatible Incompatible Inconclusive
Nearest neighbor 9 1 0
Farthest neighbor 7 2 1
Early flowering 7 1 2
Late flowering 9 1 0

 

Here I’m considering a cross compatible if 75% or more of the styles shriveled, incompatible if 25% or less shriveled, and inconclusive if it is anywhere in between. We’ll go back tomorrow to check on crosses that weren’t either 100% shriveled or not shriveled and see if any more styles have shriveled in that time.

Hopefully we’ll be able to repeat this process on several more remnant populations this coming week!

Project status update: The mating scene (remnant asynchrony, isolation, and incompatibility)

This project investigates the role of three fundamental constraints on mate availability – temporal asynchrony, spatial isolation, and reproductive incompatibility – in remnant Echinacea angustifolia populations. During the summer of 2014, we conducted two studies related to The Mating Scene project. In the first study, we mapped 991 Echinacea plants and monitored the phenology of 1360 flowering heads across 31 remnants to quantify spatial isolation and flowering asynchrony. At the end of the season, we harvested 193 flowering heads from 25 remnants to assess seed set. In the second study, we performed 364 pollen crosses to characterize patterns of reproductive incompatibility within 10 remnants. With the data collected in 2014 and subsequent years, we aim to elucidate how the interactions between temporal asynchrony, spatial isolation, and reproductive incompatibility influence reproductive fitness in fragmented prairie remnants.

site # of flowering plants # of flowering heads # of crosses # of heads harvested
1 aa 60 83 36 5
2 alf 63 78 6
3 btg 3 3 2
4 dog 1 2
5 eelr 33 17 28 5
6 eri 38 54 5
7 eth 9 46 5
8 gc 6 6 3
9 kj 7 8 5
10 lce 90 70 24 5
11 lcw 51 95 24 5
12 lfe 64 103 24 5
13 lfw 89 57 24 6
14 ngc 8 5
15 nnwlf 2 13 5
16 nrrx 20 25 5
17 nwlf 13 16 5
18 on27 92 96 42 5
19 ri 82 112 44 5
20 rrx 43 47 33 5
21 rrxdc 3 3 2
22 sap 29 13 5
23 sgc 8 243 5
24 SppE 92 81 41 42
25 SppW 51 38  44 42
26 th 8 9 5
27 tower 7 11 5
28 waa 4 8
29 wood 4 4
30 yohE 4 5
31 yohW 7 9

Start year: 2014

Location: Phenology in 31 total remnants, compatibility in 10 remnants

Products: The phenology and compatibility datasets need to be made readyR. The harvested flowering heads are being processed at the Chicago Botanic Garden.

Overlaps with: phenology in six remnants, fire and flowering at SPP

Tripod Dog

Today we spent the morning doing remnant phenology. It seems that we are getting to the end of flowering and phenology is going faster and faster. During phenology we collected pollen that will be freeze dried and used for crosses next summer! Woah! While I was collecting pollen from the single flowering plant at the DOG site, the elusive three legged dog came to visit me. She fell down by me and panted while I collected the pollen. photo (13).JPG

In the afternoon we furiously measured Experimental Plot 1. Gretel and I raced other groups aswell as each other, finishing four rows before we called it a day and headed in.

Personal projects and P2 measuring

We spent the morning working on our personal projects. Elizabeth assessed style shriveling on her crossed flowers at Yellow Orchid Hill, where, she reports, flowering has recently passed its peak. Meanwhile, Claire and Jared performed crosses on the focal plants on the west unit of Staffanson. In P1, Will worked on his pollen preservation experiment and the Pollinator Posse (Keaton, Maureen, and Jennifer) surveyed P1 phenology. Further afield, Alli continued her flowering community analysis.

But the real action was at Hegg Lake, where I finished my first round of aphid additions to Echinacea angustifolia, E. pallida, and their hybrids in P7. I have almost doubled my efficiency since starting the additions, performing 20 additions in a little over an hour. I also surveyed the phenology of the 18 E. pallida flowering in the restoration nearby. Aphid survival and flowering phenology may seem pretty disparate topics–and they are–but they both inform our understanding of the consequences of introducing a non-native but closely related Echinacea species. Do they support the same aphids? How about their hybrids? How likely are they to hybridize? How much does their flowering phenology overlap? It’s hard to stick to just one question.

Doubtless inspired by my example, the rest of the team came to Hegg in the afternoon, where we measured plants in P2. Many of us we were able to increase our efficiency by working alone instead of in pairs, and row by row we progressed eastward. Less than an afternoon’s work remains.

An Illustrated Recap of Field Activities on July 16th, 2014

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