Field Notes from Pennsylvania Mountain Natural Area
from MALT Research Interns Elsa Godtfredsen and Camille Oster
from MALT Research Interns Elsa Godtfredsen and Camille Oster
Hello! I'm Camille Oster, a Missouri native and recent graduate from the University of Missouri with a degree in biology focusing in evolution and ecology. For the past two years I've been working with Dr. Candace Galen at MU studying plant pollinator interactions. While I loved our field site in Missouri's tallgrass prairies, I'm delighted to join in on the research happening here in Colorado's alpine. This summer I'll be studying formica ants and how changing climate is impacting their interactions with alpine wildflowers. Aside from research, I enjoy hiking, biking, running, and anything outdoors.
End of the Bloom
This week we said farewell to Pennsylvania Mountain. It’s been an incredible summer of field research, and we are all sad to see it go. Our flowers have reached the end of their blooms, and Penn’s landscape looks less colorful each day. In fact, this week’s flower phenology count took the least amount of time of all summer.
An unfortunate facet of scientific research, especially biological sciences, is an inordinate amount of waste produced, usually plastic. Most field research requires marking the natural landscape with tags or flags. Some of these must remain season to season for long term research. Any markings from our research that could be removed, however, we made sure to pick up this week. This ranged from tiny metal tags and nails to heavy wooden bee boxes, making our hiking load a bit tougher. Despite the extra weight, we were glad to pick up what looks like litter to anyone hiking on Penn.
This research opportunity has taught me so much in terms of research planning and the difficulties of field biology. I am grateful to MALT and Dr. Galen for this internship and guidance, to my field team colleagues for their help and friendship, and of course to Jolene the dog, without whom Penn would be much duller.
Week 8, August 3-7, Camille Oster
Sacrifice in the Name of Science
Next week marks our last day of counting flowers to study phenology. While this is our eighth round of flower counting, no week has been completely the same. We have had the opportunity to see plots of different elevations and wetness come into peak flowering and fall out of it again. To someone who has no interest in plant life, the mountain might look as if it’s in full bloom all summer. In fact, flowering species are waxing and waning at their own pace throughout the season. I encourage any outdoors enthusiast to get on a first name basis with the native plants around them. Say hello to buckwheat and columbine!
As I wrote in my previous post, most of my time studying alpine dandelion involves siting and watching a flower, waiting for it to be pollinated. Unfortunately, there are a couple issues with this method. Firstly, it can take hours for a single pollinator to show interest in your plant. Secondly, I am studying both bumble bee and bee fly pollination, and cannot control which shows up or how many replicates I have of each. As a backup, I am also replicating previous methods that use pinned, dead pollinators to brush across a dandelion and copy pollination. Regrettably, this means I had to capture and sacrifice three bumble bees and bee flies. While killing any important pollinators should be discouraged, I made sure to not kill any queens. Here you can see a Bombus sylvicola worker covered in pollen. With these supplemental methods, I can make sure I have a complete data set of pollination and seed set. Week 7, July 27-31, Camille Oster
Now that we’ve reached late season in the alpine, I’ve begun working on another research project with a later flowering plant: Taraxacum ceratophorum. Better known as alpine dandelion, this aster is a different species from the introduced common dandelion you find in your backyard: Taraxacum officinale. T. ceratophorum is distinguished by having sepals that point up rather than out and down and leaves with little to no serrated, toothy edges. Its’ flowers are frequently visited by bumble bees and bee flies, among many other insects. Dandelions are often considered nuisances or weeds, but if you look close at the Dr. Seuss-esque flowers, you might find them as cute as I (or bumble bees) do.
My experiment compares the pollination effectiveness of these two hairy pollinators, bumble bees and bee flies. This research is a continuation of the experiments of Emelyn Piotter, a previous MALT intern and a former colleague of mine in Dr. Galen’s lab. She studied how the two insects differ in pollination behavior and how their setae (hairs) pick up pollen grains, showing that bumble bees are more successful in both fields. This experiment takes those findings and asks if T. ceratophorum can produce more seeds from a visit by a bumble bee or a bee fly. My experimental setup has three treatments: control flowers are openly pollinated by any insect, while two experimental groups are excluded from pollinators using a stake and tulle netting. Once an experimental plant is flowering, I uncover its’ veil and allow either a bumble bee or a bee fly to forage, recording the amount of time spent foraging. For all three treatments, I also count the number of open flowers. Yes, you read that right, a dandelion bloom is actually an inflorescence made up of dozens of flowers, why it’s able to produce so many seeds you’ll see float away. Once any inflorescence is finished blooming, I bag it up and count how many seeds it was able to produce from pollen delivered. We expect to see more seed set from bumble bee pollinated plants than bee fly pollinated plants because they spend more time on blooms and their hairs hold onto pollen grains better. Lastly, I am also video taping control plant blooms during peak pollination time to get an idea of what pollinators have more ecological importance to dandelions.
While this experiment seems simple enough, nature doesn’t always cooperate with data collection. I might end up with most of my plants pollinated by bumble bees and only a few by bee flies just by chance, or vice versa. Also, waiting around for a pollinator to show up to one plant can take anywhere from minutes to hours. If you see me staring at a plant for what seems like way too long, I’m not crazy; I’m just doing science!
Week 6, July 20-24 , Camille Oster
Saying Hello and Goodbye to Flowers
This week rare sights became common friends on phenology day. Whipple’s Penstemons (Penstemon whippleanus) prominent dark purple flowers littered the slopes, replacing some other flowers that we are seeing less and less of as the season continues. We are in our last few weeks of our field season and the mountain is changing from the continuous heat and lack of rain. We have started to say things are getting “crispy”. We also have started to see the Harebells (Campanula rotundifolia) which are charismatic members of the bellflower family. They have begun to open their jewelry box worthy blue bells, which Zack has told us can be a marker of the end of the highest point of flowering.
I have definitely seen this phenomenon in my individual project. Dwarf clovers (Trofolium nanum) have ended their flowering period for the summer. Their small cushions are full of dried flowers from the bottom of the mountain to the summit. Parry’s Clover (Trifolium Parryi) is harder to nail down with its flowering timing. In lower elevations almost all of the distinctive pink blooms are dried up, their flower duration marked “finished” on my data sheets. At the mid and higher elevations although, some plants are yet to flower or are in mid bloom. Alpine Clover (Trifolium dasyphyllum) seems to have a similar pattern. It has been lovely to visit the same plants each week to monitor the flower stage of my marked individuals because it allows me to become familiar with flower timing of these species and the changes in different parts of the mountain. In the next few weeks its likely that flower density will continue to go down as we slide down the tail end of the season, but we have had a lot of rain in the last few days so we will see!
As a last note, I wanted to do a little species highlight that we saw this week. Zack led us around some rocks until we spotted the strangest thistle I have ever seen. It’s well known common name is the Mountain Thistle (Cirsium scopulorum), but as Zack led us to it he introduced it as the Alien Head Thistle and I could see why. It had a huge grouping of green flowers that formed a head like shape, underneath which its sharp barbed leaves burst. I took a picture of it for size comparison and it was very close to the size of my head! Definitely a plant to look out for when hiking in mountainous areas in Colorado, especially because it is a native thistle!
Week 6, July 20-24, Elsa Godtfredsen.
Rain on the Research Parade
While field biologists spend much of their time leading up to field season preparing for research, so much of our work can be unpredictable and impossible to plan for. Study species can be difficult to find. Flags and labels can move or just disappear entirely. Weather can be erratic and even dangerous. We ran into a couple of these hiccups this past week. Our schedule for flower and bee phenology is well planned out. On Mondays we collect flower phenology data and on Tuesdays we set out microphones to collect bee phenology data. The problem with our plan lies in Mother Nature not caring about our plan. On Monday at about noon, much earlier in the day than usual, some intimidating thunderstorms started rolling in. With many of our field sites being a 45 minute hike from tree line, we elected to turn back early. Luckily, we were able to finish up our flower phenology the next day with no problem.
My research studying formica ants and P. viscosum also ran into unforeseen issues this week. My study design is built around having an equal number of plots with formica ants present and without. As the season has progressed, ants and ant damage to flowers have appeared in some of my “ant-less” plots where they historically have not been found. While this lends support to my hypothesis that formica ants are moving up in elevation, it makes things messy for my research. Similarly, my plots on the summit of Penn most definitely do not have ants, but are weeks behind in flowering compared to my lower elevation plots. Unfortunately, these problems do not have as easy of a fix as bad weather. But such is the way of field work, we have to work with what we’ve got.
On a lighter note, we have some lovely new blooms on the mountain including Rhodiola rhodantha, aka queen’s crown, and Penstemon whippleanus, common name whipple’s penstemon.
Week 4, July 5 -July 11, Camille Oster
Catching the Bumble Buzz And Sowing the Trifoliums
This week my main focus was monitoring Trifoliums (clovers) for my individual project. My “wet” and “dry” sites are located at many different places on the mountain and so a full day of monitoring also means a full day of hiking. When I get to a site my first task is to find my marked plants. Each marked plant has a circular metal tag below it, so it can take some sharp eyes and detailed notes to locate them in our 10m by 30m plots. Luckily after this week and last, half of them have pollinator exclusive mesh enclosing them and so are much easier to spot. After I locate a marked plant I then proceed to search for buds. To have full span of data for flower longevity, it is best if I can mark flowers when they are in the bud stage (flower is closed and inaccessible to pollinators). This way I can get the full flower duration from the flower being closed to full bloom to its last phase when the flower is dried out and there are no longer rewards for pollinators. If I find any buds while inspecting my marked plants I mark them with small sowing pins at the base flower. It is funny what house hold objects can be useful when it comes to field work. After the first marking of buds every time I return I will check in on the progression of the bud. I use a scale of 1-3 to qualify the stage of the flower, 1 being the bud stage, 2 being full bloom and 3 being dried out. I also count the total amount of blooming flowers on the plant and am hoping by the end of the season I can get the full flower duration for 3 flowers per marked plants. Currently I have around 60 marked plants at my 10 plots which I will be monitoring for the rest of the summer.
The other thing I was working on this week was placing small microphones at my marked plants which have an flower in full bloom to measure bumble bee visitation by buzz density. I try to get out to the field early on these microphone placing days because ideally the microphones are recording at the plants for 5-6 hours. I place the Chapstick sized microphone at “flower level” slightly away from the plant. The microphones have furry wind covers that help reduce excess noise so when I leave plots they often resemble small animals kneeling by my flowering plants. At the end of the time period I return and pick up the microphones. The recording will then be processed by a program on the application Audacity and I will be able to know the frequency of bumble bee visitation to each plant because of the buzzing recorded by the small microphones. I am interested to use this data to investigate if water stress affects flower duration and therefore affects pollinator visitation. I will also be doing this microphone routine every week. A treat from this week was my first spotting of one of my favorite flowers on the mountain, the Colorado Columbine (Aquilegia caerulea). I spotted these elegant friends wedged between two rocks on the false summit and it brightened my whole week. Week 4, July 5-11, Elsa Godtfredsen.
To Bee or Not to Bee?
On Wednesday we chased golden hour on highway 9, marveling at how our mountain was outlined in the days last breathe of light. We hiked up our familiar trail as the mountains around us turned into peaks of pink sherbet and the chilly air of alpine night began to creep onto our fingertips. We were taking this late night adventure to check if any bees had nested in “bee boxes”, which are small wooden boxes that resemble bird houses. We had placed these boxes on the mountain a few weeks earlier, the hope being that queen bumble bees would use them as nest sites and therefore allow us to monitor their behavior for the rest of the season. The check had to be performed at night because during the day the queen could be out foraging and we could miss her presence. Zach demonstrated to us how to check the boxes by leaning down, unscrewing the lid of the box and poking the cotton inside. He explained that if a queen is present, we would hear a sharp buzz sound that is defined as “defensive buzzing”. We scurried around the sunset lit hillside, poking our hands into cotton and listening carefully for any back off buzzes. The mountain was sadly quite except for our footsteps. There were no occupied bee boxes. This could be for several different reasons. It is possible that we placed the boxes too late and missed the time period where queens are searching for a nest. It is also possible that there are less queens nesting in the area in which we placed the boxes then in previous years. It is hard to pin down a reason why our bee box’s remained empty but it has encouraged us to find other ways to study bee behavior. We have been attempting to find out the locations of natural bee holes, which are bee nests made in holes in the ground by queen bumble bees. We have found their locations by observing bumble bees and attempting to track them back to their nest. This can be a highly adventurous activity, since bumble bees can fly very fast and are easy to lose track of as they zip along wind currents. So far we have found seven natural bee holes which we will observe for the rest of the season and hopefully find some more along the way!This week I was also trying to discourage bumble bee visits at some of my plants for my individual project. It may seem counter intuitive but pollination of flowers actually has the ability to decrease flower duration for a plant. To avoid this variable, half of my plants in which I will measure flower duration are now “pollinator excluded”. I achieve this by putting somewhat of a tent over the plant, made up of a wooden stake, mesh fabric and nails that pin the contraption to the ground. They are quite endearing looking, resembling a kind of small fairy tent sticking up from the hillside. These contraptions will remain on these plants until the end of the season and I will be monitoring flower progression twice a week. Much fun to come! Week 3, June 29-July 2, Elsa Godtfredsen
This week the phenology team was down a member on our flower count day as Elsa was under the weather. With any field work, it’s important to stay flexible; we adjusted our data collection methods and thankfully still got all our work done on time. Some lovely blooms are becoming more common, such as this blue and purple Penstemon. A rarer sight that caught my attention was this white Polemonium viscosum bloom. Flowers can vary in color due to a genetic mutation, environmental conditions, or anything in between.
I’d like to discuss the bumble bee and formica ant relationship study methods in a bit more detail. In order to observe P. viscosum with and without the pressure of nectar robbing from ants, I have chosen six phenology plots with ants present and six without. The plots without ants were difficult to find because it appears that formica ants are becoming more common and moving up in elevation. At each plot, I randomly selected 15 skypilot plants that I observe until they produce buds. Of those 15, I randomly selected 5 plants to exclude ants from. This is where things get sticky. I use a plastic straw to cover a P. viscosum inflorescence stalk and apply Tanglefoot, a sticky insect trap, to prevent ants from ever reaching an open flower. You can see a photo of my ant exclusion setup here, but trust that a photo does not capture how messy and gummy things get. This method gives us a view of inflorescences without ants at any elevation. From these 15 replicates, I will weekly measure flower dimensions and record if flower styles have been removed. Using this data, I expect high alpine plots lacking ant damage to have wider flowers than lower alpine plants that need to protect from ant nectar robbing.
Week 3 June 29- July 2 Camille Oster
Dining and dashing in the plant world
What a week! Long term phenology studies are in full swing, and my and Elsa’s research is picking up as well. It’s becoming daily routine to hike up to Pennsylvania mountain’s summit. Afternoon thunderstorms are now included in our schedule as well. We were caught in a moment of hail this week! The mileage and weather might be beating down on us, but Colorado’s summer blooms bring the spirits right back up.
If you frequent mountain hiking trails, you’ve probably seen Polomonium viscosum, whether or not you realized it. Also known as alpine skypilot, this lovely purple lady is often visited by bumblebees that give pollination service. Less welcome visitors include formica ants. These industrious thieves nectar rob, meaning they steal nectar, but don’t spread pollen between plants. Sort of like dining and dashing of the plant world. In the process, skypilot’s style is chewed off, preventing the flower from ever producing seeds.
These two relationships, ants and bees, have shaped Polomonium flower dimension. Bees prefer larger, wider flowers to pollinate while ants prefer shorter, wider flowers to nectar rob. My research is evaluating how these pressures alter flower shape in various habitats. Formica ants are not found on the summit or in the swale, and in these areas we can expect bumblebee pollination to be the dominant pressure. This summer I will be monitoring skypilot flower shape and ant damage of randomly selected flowers in several phenology plots. This week I established my flowers to monitor and from here on out I will be observing blooms from bud to senescence. Week 2 June 22-26 Camille Oster
Wet or Dry? The Clover Question
This week a new host of floral characters were jotted down on our phenological data sheets. Old Man of the Mountain (Hymenoxys grandiflora) followed the sun with its bright yellow inflorescence, turning certain hillsides into giant sun dials. We found it in multiple of our phenology plots and it brightened our day on Monday, the day we always collect our phenology data.
The rest of the week was spent on the set up for my individual research project for the summer. I am interested at looking at how drought effects the flowering success of alpine plants. Snow is an important variable in high altitude settings since snow melt is a major water source for alpine species. Recent studies have shown that there is a trend for accelerated snow melts, meaning a spike of water earlier in the season and leading to a longer period of drought later in the summer. This can cause a large host of problems, such as a phenomenon called phenological mismatch. This term can refer to when plants period of flowering is not matched with when pollinators are present. This can be an effect of earlier snow melt since the influx of water earlier in the season can cause accelerated phenology of plants.
I am planning on studying how flower duration/longevity could be affected by drought. This will be an interesting thing to investigate since how long a plant will flower may effect the degree to which phenological mismatch may impact its pollination success. In general, alpine species tend to have longer flower longevity then their lower elevation counterparts to compensate to less frequent pollinator visitors. My study species are three clovers in the genus Trifolium in the Fabaceae (Pea) family: Dwarf Clover (Trifolium nanum), Parry’s Clover (Trifolium parryi) and the Alpine Clover (Trifolium dasyphyllum). I chose these species since there is some in-genus variation in flower timing and they are frequently present at phenology plots at different altitudes. The next thing I needed to decide was how to look at how water availability effects flower duration in these plants. I decided to use a sub-section of the phenology plots for my study and to qualify half as “wet” plots and half as “dry” plots depending on amount of water accessible.to plants. I measured water availability by looking for presence of water loving or “indicator species”. These are species, for example the Marsh Marigold (Caltha palustris), which only grow in areas with high water content. I used six different indicator species. When two or more species were present, the plot would be considered “wet” while if one or less indicators were present, a plot would be considered “dry”. It was a week of very wet and very dry hiking boots and I am excited to start marking my study plants at these plots for monitoring in future weeks! Week 2, June 22-26, Elsa Godtfredsen
A Beautiful but Especially Breathtaking Start to the Season
My first view of Pennsylvania Mountain was of an impending mound from highway 9 with two humps and a bit of an intimidating continence. As we whipped towards the trail head, which rests around 10,500 feet, instead of my stomach flipping my lungs gave a twirl. I had only been back in low oxygen high beauty Colorado for a few days and my body was definitely feeling the change.
As our first day went along although, the mountain views were more than enough to fuel my legs up the almost 3,000 feet to the true summit. We were not hiking for just the views although. Along our wandering trail through the lower elevation area of the Krummholz, which is full of Bristle Cone Pine (Pinus longaeva) and willow bushes (Salix sp.), we encountered our first of 25 phenology plots. The first plot was indicated by ragged plastic flags from the previous season and marked an area that was around 30m long and 10m wide. These historic plots were established in the late 1970s and have been used by multiple groups of scientists to study phenology of alpine plants.
Phenology is referring to the timing of seasonal natural phenomena such as when plants bloom and put out seed. In our case, we are most interested in the phenology of flowering for eleven alpine herbs that are pollinated by Bumble Bees (Bombus sp.). It is still early in the season, so even though we had a relatively early snowmelt, there were not many of our interest species blooming. The few early bloomers scattered the ground of the plots with bright splashes of color. Sky Pilots (Polemonium viscosum) peeked their bright purple tubular flowers from fernlike leaves while dwarf clover (Trifolium nanum) lay close to the ground and raised soft pink flowers up from thick leafy beds. We will be monitoring this plot every week for the rest of the season so there will be sure to be more to come. Although it’s a pleasure to count and observe these alpine jewels, it is also an honor to be a part of such a long running research effort. The ability to use data from a span of 40 years allows us to ask interesting and important questions about how climate change is impacting alpine plants and their pollinators. Week 1, June 15-19, Elsa Godtfredsen.
2019 Field Notes from Pennsylvania Mountain Natural Area
from MALT Research Interns Emelyn Piotter and Maya Rayle.
from MALT Research Interns Emelyn Piotter and Maya Rayle.
“Hello! I’m Emelyn. I just graduated from the University of Missouri in Columbia Missouri (which also happens to be my home town) where I majored in Biological Science and minored in Captive Wild Animal Management. For the last two years I have worked in Dr. Candace Galen’s lab studying pollination ecology. Last summer I was able to join Dr. Galen’s graduate students and the MALT interns in Colorado and had the opportunity to conduct some research of my own on Pennsylvania Mountain. I studied how the hair structure of different insects affects their ability to collect pollen. After spending the last two semesters counting and measuring pollen grains and insect hairs I still have a couple of unanswered questions that I will be following up on this summer.”
2019 Field Notes
At each of the three bee box sites at different altitudes, we pollen-swab workers. The purpose is to find out which flowers they’re visiting throughout the season. To catch the bumblebee workers, we sit a meter or two from the bee box with a butterfly net placed underneath the entryhole. When a worker bee flies into the colony, we catch it in the net, then transfer it to a falcon tube, then place it in a cold lunch box. Once the bee has cooled off, it won’t be able to fly away so it’s much easier to handle. Then, we use a small cube of jelly (made out of gelatin) that’s just a few millimeters wide in order to swipe the bee’s body. We’ll then store the gelatin cube in a labelled microcentrifuge tube to make slides with back at the house.
We’ve also been collecting pollen from different families of flowers in the area so we can identify pollen from the bees -- a pollen library of sorts. We’ve been collecting pollen off of workers once every two weeks at each site. This will provide useful information about what flowers workers are foraging from, and how this changes throughout the season. Maya 08-11-19
Acoustics of Flower Visits
Every Friday, we set out microphones to do acoustic monitoring of bee activity on flowers. In the flower plots that have all of the flowers we monitor (there are eight or so flower species that we’re interested in), we visit each plot to set up microphones. Right now, we to to three flower plots.
For the past few Fridays, Zack and I have gotten up early then hiked up Penn Mountain. We first go to a flower plot above the second slope, then one near the false summit, then one near the true summit. In each flower plot, we check which flowers are blooming. Even though these flower plots have all of the flower species at some point in the season, not all of the species bloom at once. Last week, the plots had trifolium nanum, polemonium viscosum, and mertenzia.
Once we check which species are blooming, we pick out the patch of flowers from each species with the most flowers blooming to set up a microphone. This involves bending a wire into a twist to hold the microphone, leaving the microphone suspended above the plants. It’s best to place the microphone a little ways away from the flowers so it doesn’t physically interfere with bee activity. We also place a muffler on the end of the microphone to reduce wind sounds. You can see the setup in the photograph.
We then leave the microphones out for 6 hours or longer before Emelyn and Mackenzie go to pick them up. After that, we’ll send the audio to a collaborator who’s come up with an algorithm that subtracts the audio from a nearby control microphone where there are no flowers from the microphones at each flower species. This gets rid of background noise such as airplanes, wind, and any other odd sound that isn’t a localized buzz.
The purpose of this microphone experiment is to listen to bees foraging on flowers. Our microphones will pick up bee buzzes within a range of one meter, so we can tell when the bees are foraging on the chosen species of flower. We can learn about bee preferences, what sounds they make when they forage, and we can hear arrivals, departures, and visitation buzzes.
One of the most important pieces of information we get out of this is to measure if peak bee activity matches peak flowering. We get our flower data from flower phenology (counting flowers in plots each week), and bee activity comes partially from this. Since last year was so dry, there was a large mismatch between peak flowering and peak bee activity, such that the flowers peaked long before the bees did. This can be really hard on colonies because they rely on flowers for food. Studies suggest climate change can exacerbate mismatches because plants and bees use slightly different biological indicators for when to begin flowering or to come out from their dormancy period. Our work with microphones will help to measure mismatches in the short term, season to season. A mismatch caused by last year’s drought is not necessarily climate change related, but since climate change is predicted to cause more frequent droughts and warmer temperatures on average, a comparison between a drought year and a normal or even snowier-than-average year like this year is useful for studying the effects of climate change on bee flower mutualisms. - Maya
The Life of a Bumblebee
Since our work focuses so much on bumblebees, I thought it would be worthwhile to take the time to explain the bumblebee life cycle and a little about bumblebee behavior.
Bumblebee queens are born the previous summer, and spend the winter underground. They generally burrow six inches or so into the dirt, and live off of fat reserves. Alpine bumblebee queens face extreme winter conditions, and are often buried deep under the snow. Queens are much larger than workers, which helps them survive the cold. There’s a rule in ecology called Bergmann’s Rule, which states that across geographic regions and across different species, colder climates tend to have larger animals, and warmer climates tend to have smaller animals. This is because a larger body means a lower surface to volume ratio, which helps an animal to conserve heat. Bumblebees are generally large and queens are especially large which allows them to survive in colder environments.
In the spring, when the temperature warms sufficiently, the queens emerge to feed off of nectar. Then, they begin to hunt for a nest site. We’ve seen a lot of queen bees hunting -- they fly low to the ground, moving along methodically as they search for holes in the ground. We’ve been placing wooden boxes with an entrance and exit hole and a thick layer of cotton inside to provide a good artificial nest site similar to a natural site.
Once a queen finds a nest, she makes frequent trips all day, each trip lasting 30 minutes or so to collect pollen and nectar. She’ll bring this back to the nest to either save it or consume it. She builds a wax mound (she can secrete wax from her body), and then lays her first round of eggs. It takes about three weeks for them to mature into larvae and then into worker bees. During this time, the queen sits on the wax mound to keep the larvae warm by shivering her body. Bumblebees are excellent thermoregulators.
After the first workers are matured, the queen will hardly leave the nest. She’ll spend most of her time laying and incubating eggs. Worker bees either forage or guard or clean the nest. Worker bumblebees that forage split into three working groups: nectar gathering, pollen gathering, and a group that does both and fills in where needed.
Later on in the summer, the colony produces male bees, which go out to attempt to mate and do not return to the nest, and new queens. When the new queens mature, they leave the nest to find males to mate with, then they spend the rest of the summer feeding on nectar and pollen to store up for their winter underground. Queens only live one year, so the old queen and the rest of the colony dies, with only the new queen surviving. Sometime in the fall, the new queens will burrow, and the cycle starts again. - Maya
A snowy start: So far this field season has been quite different from last years. The summer of 2018 was an extremely dry year and this summer is much wetter than usual. At this time last year virtually all the snow on Pennsylvania Mountain had already melted, flowers were in peak bloom, and pollinators were out all over the mountain. Because of all this winter’s snow the plants and pollinators are getting a much slower start. Right now on Pennsylvania Mtn. bumblebee queens have just started emerging from their winter hideaways underground and only a couple of wildflowers have started to bloom. We even need snow shoes to access many areas. A lot of the research we do on Pennsylvania Mtn. involves studies that span multiple years so the extreme difference in the conditions between last year and this year allow us see how plants and pollinators are impacted by different temperature patterns.
Because dandelions, bumblebee workers, and bee flies aren’t out yet I can’t do much work on the research I have planned for the summer other than writing up methods for how we plan to conduct different studies and making sure we have all the materials we need. It will likely be two more weeks before the native dandelion species starts to bloom. The slow start isn’t unwelcome though as it’s giving us ample time to adjust to the altitude. Until the dandelions start blooming I will primarily be helping Zack, one of Dr. Galen’s graduate students, with his work on bumblebee acoustics. I have spent the last couple of days setting up bee boxes (which are essentially bird houses but for bumblebees), monitoring them for activity, and taking note of what flowers are blooming in the area. I also helped analyze some of last year’s bumblebee acoustic data and got to learn the basics of software program called “Audacity” that we use to look at audio files. - Emelyn. 06-26-19
A Snowy Start!
So far this field season has been quite different from last years. The summer of 2018 was an extremely dry year and this summer is much wetter than usual. At this time last year virtually all the snow on Pennsylvania Mountain had already melted, flowers were in peak bloom, and pollinators were out all over the mountain. Because of all this winter’s snow the plants and pollinators are getting a much slower start. Right now on Pennsylvania Mtn. bumblebee queens have just started emerging from their winter hideaways underground and only a couple of wildflowers have started to bloom. We even need snow shoes to access many areas. A lot of the research we do on Pennsylvania Mtn. involves studies that span multiple years so the extreme difference in the conditions between last year and this year allow us see how plants and pollinators are impacted by different temperature patterns.
Because dandelions, bumblebee workers, and bee flies aren’t out yet I can’t do much work on the research I have planned for the summer other than writing up methods for how we plan to conduct different studies and making sure we have all the materials we need. It will likely be two more weeks before the native dandelion species starts to bloom. The slow start isn’t unwelcome though as it’s giving us ample time to adjust to the altitude. Until the dandelions start blooming I will primarily be helping Zack, one of Dr. Galen’s graduate students, with his work on bumblebee acoustics. I have spent the last couple of days setting up bee boxes (which are essentially bird houses but for bumblebees), monitoring them for activity, and taking note of what flowers are blooming in the area. I also helped analyze some of last year’s bumblebee acoustic data and got to learn the basics of software program called “Audacity” that we use to look at audio files. - Emelyn 06-24-19
2018 Field Notes
The summer of 2018 has been an intriguing season for alpine ecology on Pennsylvania Mountain. Between the early snowmelt, higher than average temperatures, and the wildfire directly south of us, I’m surprised any of the plants we were working with survived to set seed! I am used to arriving to the field site in early June and having to trek through feet of snow just to be able to hike up the mountain a bit. This year however, early June looked like early July! This was true not only for the snow levels, but also the flowers, because as soon as the snow melted some flowers had already started to bloom. One possible drawback here is that there could be a disconnect between the flowering time and the timing of pollinators. This could make it more difficult for flowers to reproduce if their animal partner is not present when they put on their colorful display, and it could also make it more difficult for pollinators to survive late in the season when the flowers are no longer blooming as much. Part of my colleague Ellie’s research this summer will hopefully shed light on whether that happened.
Overall for the purposes of my experiment with dandelions, the weather seems to have been in our favor. During the drought conditions in late June, I was very worried that the dandelions would fail to set their seeds. However, in early July a mild monsoon season rolled through the area, dampening the wildfire and giving the wildflowers much a needed boost. While we don’t know the overall effects of this early and drought-ridden year, it is important to monitor things like flower abundance and bee activity (both projects of our field crew) so that we have a better idea of how the changing climate will affect ecosystems in the future.
That said, many plants and insects are still active at this time of year. For example, I recently found this cool insect on the top of Horseshoe Mountain. At first it appears to be a bumble bee, standard for the habitat. However, upon closer inspection this is definitely a fly! The colors may fool you, but look at the eyes and wings and you will see that they are fly-like instead of bee-like. One of the big clues here is that this creature has two wings -a fly trait- while all bees have four wings. The fly likely evolved to look like a bee for defense, as mimicking a bee with a stinger is likely to dissuade predators from bothering the fly.
Another type of organism still persisting in the late summer alpine is the dandelion. However, the one pictured here is not just a common dandelion, rather this is a type of dwarf alpine dandelion! In addition to the size and habitat differences (the dwarf grows in high alpine habitats, while the common dandelion grows along low alpine trails and down in towns), there are physical differences evident even in this close-up photo. Specifically, notice the black-grey seeds of this dwarf dandelion. In Colorado, this is a trait specific to just a couple species of high alpine dwarf dandelions. If you look at dandelion seeds from your yard or near a lower elevation trail, you are likely to see brown-straw colored or red seeds, but not these striking black ones. This is just one trait of many that can be used to distinguish between different types of dandelions, and if you are really interested in learning more about identifying dandelions, check out the Flora of Colorado book!
Austin Lynn 08-13-18
A PUFF OF CO2?
The field season is beginning to wrap up here on Pennsylvania Mountain! We are continuing to run through our experiments and collect as much data as possible in these final weeks. Time flies when you're doing field work!
This week, we are starting one final experiment. We want to see if the bumblebees in our nest boxes will respond to puffs of carbon dioxide entering their nests. We hope to collect some preliminary data to give us a better idea of how we might conduct a longer study next year. As you may know, animals (and plants) release carbon dioxide when they exhale during respiration. Studies have shown that some insects can detect varying levels of CO2 in the air. Bumblebees would experience increased concentrations of CO2 inside their nest if a curious potential predator was to breathe into the nest opening as they were looking for food inside. If the bumblebees are able to detect this, they might also make some kind of audible response to warn the predator to stay away, or to alert the other members of the colony. How do we test this? Although we could act like a predator and breathe into the nests ourselves, we decided not to risk an angry bumblebee encounter and try a different strategy. We are instead using small canisters of CO2, like those used to inflate bike tires, to emit controlled puffs of CO2 into the nest opening. We will pair the CO2 puffs with some different buzz playbacks like the ones we are using for other experiments to see, for example, if the combination of a defensive buzz and this CO2 sends a strong danger signal to the bees inside and elicits a response. As with all these experiments, we will have our small microphones set up inside the nest to hear any potential responses from the bees. We have started so many exciting projects this summer, and we're just beginning to scratch the surface of the many interesting findings that are sure to come!
Ellie Harrison 08-06-18
As a botanist, I don’t typically have to deal with concerns of mortality in the organisms that I study. However, I have continually branched out to study how plants interact with animals that pollinate them, and as such I must undergo one of the typical entomological rituals of lethally collecting insects for science. In order to reduce the amount of insects we must kill for our research, one thing we can do is chill the bumblebees so that they slow down to a manageable speed and then we can collect pollen from their bodies and the identify them by looking with a magnifying glass at the minute features of their bristles. This allows us to release the bee back into its original habitat following our sampling procedure. Just last week I had a wonderful experience with this, where I brought several bumblebee workers back to the field and watched them warm up while replenishing their energy by feasting on dandelions. Because it was a bit cold outside, we had to watch the bees closely and sometimes bring them fresh flowers so they could feed easily even in their weakened state.
Just a bit after this beautiful moment with the bees, an intense and wintry storm rolled up to Pennsylvania mountain to drop around three inches of snow and hail for us on July 5th. I find that field work is typically like this- triumphs and set-backs always seem to follow each other. Either way, now that the storm was upon us, we had to deal with it. This storm was bizarre for several reasons, first it brought snow in the middle of the summer, but also the location of the lightning strikes were concerning to me. All of my life I have heard that thunderstorms in the rockies are dangerous because being above treeline puts you as the tallest thing around and then the lightning will be more likely to go through you as the path of least resistance. So imagine my surprise during this storm as we are running to get below treeline and we see lightning strike in front of us in the forested area that we thought was safe! Needless to say, we eventually made it to cover underneath some willow bushes where we waited out the storm. Overall this intense storm taught me that droughts are typically followed by deluges, and that sometimes nowhere on the mountain is safe from nature’s wrath! Austin Lynn 07-13-18
BUMBLE BEE MOVING DAY!
We had a big event this week in the world of our bumble bees: moving day! At the beginning of the summer, in addition to setting up our nest boxes at Penn, we also set up a few on top of Weston Pass. One of them was successfully occupied by a queen and her colony (we named this queen Winnifred, along the same lines of our other queens: Agnes, Dorothy, Opal, and Ruth). As some of you may know, a wildfire started near Weston Pass at the end of June. Because of this, we were unable to access that nest box for a couple of weeks. Now, thanks to the hard work of many firefighters and a few lucky rain showers, the fire has been contained to a safe level for the time being. However, it was decided that it wouldn’t be a good idea to plan on weekly visits to Weston for our research because of the risk of the fire starting up again. So instead, we made a plan to go out this week and move Winnifred and her colony to Penn Mountain. To do this successfully, we had to go out at sunset when we knew all the bees would be back in the box and likely asleep. The weather was perfect and the views of the sunset from the top of the pass were stunning! When we arrived at the box, we temporarily closed up the entrances and carefully carried the box back to the car. For the bumpy drive down the pass, our field assistant, Claire, had the box wrapped in towels and firmly placed between her feet to give them as smooth of a ride as possible. After the box spent the night on our porch, we took them up to Penn early in the morning and set them up at their new home! There are more flowers blooming at Penn than at Weston, so we hope they’ll be even happier and healthier than they were before— and without the risk of a fire! Good luck and happy pollinating, Winnifred! Ellie Harrison 07-12-18
One of my favorite things about working in the field is training new field scientists and planning and executing a new project with them. This year I am mentoring Emelyn, an undergraduate from the University of Missouri, through her project dealing with dandelion pollination. When working out on Pennsylvania Mountain, we collect any insect we see feeding on the plants and then once we are back at the field station we take a sample of pollen from the insect. One of the initial things we noticed is that some visitors of the dandelions seem to be quite effective, picking up lots of pollen, while other visitors don’t appear to pick up hardly any pollen at all! This observation led to the question of why certain pollinators may be better mutualists than others- is it because of the way they forage or feed from the flower, or is it a function of the hairiness of the pollinator? An exciting example that we just noticed from simple observations of how different insects feed from the flower is that the bee-flies, while covered in hair, do not appear to collect much pollen because they stand on top of the flower to forage. On the other hand, solitary bees such as the megachilidae dig deep into the tubes of the dandelion flowers to get the nectar at the bottom, and in the process they become covered in pollen, meaning they are effective pollinators.
Once we have collected the insects from the field, we take them back to the field station so we can sample pollen from their bodies. This process is shown in the photo below where Emelyn is making slides in the kitchen. To do this we use tiny cubes of gelatin that we brush against the bodies of pollinators. Doing this allows us to look under the microscope at traits of pollen that are successful in adhering to the pollinator, and compare to unsuccessful pollen that remains on the flower. If certain traits are more prevalent in pollen on the pollinator, that could suggest that those traits are evolving for a greater ability of the pollen grain to succeed in transferring to another flower, fertilizing it, and creating seeds! Austin Lynn 07-01-18
We started a new project this week! Although we are primarily using our occupied nest boxes for the study I told you about last week, they also present us with a great opportunity to study other aspects of the bees. We are starting some playback experiments, which involve using a speaker aimed at the nest to play buzzes (which we have previously recorded), then to see if we hear any kind of response from the bees inside the nest. We will play different types of buzzes with different purposes: the buzzes that they make when they fly, when they pollinate, and when they feel threatened. Right now, we are just hoping to hear any kind of reaction to any kind of buzz. It has long been assumed that bees can’t hear sounds. However, if we are able to hear distinct responses from the bees after the playbacks, we might be able to find some evidence to the contrary! This will require a lot more data collection and different kinds of experiments, but we are very excited to be collecting some preliminary data and eager to see what we find! Ellie Harrison, 07-01-18
We have had another week of sunny
weather, beautiful views, and hard work. We are working on several different
projects at once, so we are busy but learning lots! One of our biggest projects
this summer involves acoustically monitoring bumble bee colonies. At the
beginning of the summer, we set up nest boxes (wooden boxes with a small hole
in them) at different sites on the mountain. Our hope was that they would
become homes for the bumble bee queens who had spent the winter underground and
were now looking for a place to start their colonies. Bumble bees usually use
abandoned rodent holes or other similar cavities in the ground for their nests,
but scientists have found that they will sometimes use these nest boxes,
which makes it easier for us to find and study them. Luckily, a few queens
moved in! Now, our goal is to use microphones and environmental sensors (to
record things like temperature and humidity) inside the boxes to track the
growth and development of the colony, which has never been done before. With
luck, we may even hear the bees talking to each other! This past week, the
queens and their eggs were the only bees occupying the boxes. We already heard
the queens making some interesting sounds that we haven’t heard before. I am
excited for their colonies to grow and to see what we will hear when we are
listening to a box full of bees! I will be sure to report back here with any
interesting findings. Ellie Harrison, 06-24-2018