Phenology Investigations Overview

We are investigating the phenology of milkweed and the insects and pollinators that affect them to better understand how milkweed grows in different locations over time.

About Phenology

The Phenology Project is an ongoing citizen science experiment. Citizen science experiments invite individuals and students to help researchers answer big questions about the world. In our Phenology Investigations, we are working together to understand how the timing of milkweed development and interactions with insects vary across time and space.  What we learn should help people make decisions about how to restore milkweed populations specifically, and it should contribute to our learning about how to restore degraded communities more generally.  In an era of widespread loss of biodiversity and ecosystem services, these are important lessons.

Phenology is the timing of life events, like the time at which a plant sprouts, flowers, or dies. Phenology can be a fixed genetic trait that contributes to local adaptation; for example, plants from colder areas may tend to germinate at colder temperatures than those from warmer regions. Phenology is also a trait that can change depending on cues in the environment; for example, germination may happen early or late depending on moisture and temperature in any given year. Early evidence from our studies suggests that plants from different regions show different phenologies, but we don’t yet know if that means they experience different interactions with invertebrates. If they do, then it could be important to plant locally adapted seed varieties.

Phenology is also important to study and document due to climate change. Climate change will continue to cause changes in long-term average temperature, growing season length, precipitation patterns, and the frequency of natural disasters. These changes can influence the survival, distribution, phenology, and ecology of many species. For example, evidence suggests common milkweed has shifted its flowering phenology: blooms are starting earlier and ending earlier as global temperatures increase (Howard, 2018). If species that interact, such as plants and their pollinators, respond differently to climate change, a “phenological mismatch” may occur in which the normally interacting life stages no longer align. The fitness consequences of such mismatches can be severe (Yang and Rudolph, 2010). Mismatched phenology can impact a plant’s risk of herbivory, or getting eaten by herbivores depending on the emergence of both species in the season. A change in flowering time could also impact which species are available for pollination, the process that moves pollen between plants allowing sexual reproduction. 

We want to understand how variation in phenology and development of a plant affect the probability of herbivory and pollination in order to predict the impacts of moving plants to new locations and climate-change induced shifts on plant phenology. We hypothesize that early emerging plants might escape herbivory, and that early and late flowering plants might experience less pollinator visitation. Additionally, we hope to develop a more complete understanding of the regional and temporal differences in the nature, timing, and intensity of interactions between milkweed and invertebrates.

We aim to test the hypotheses that 1. Atypical phenology allows plants to escape herbivory but reduces pollination rates, 2. Herbivory is most intense at the range center and pollinator visitation rates decrease with latitude, and 3. Invertebrates interact with different plant phenophases (developmental stages) in different regions and as the climate warms. The following studies are designed to help us do just that. Consult the project breakdowns below to see which investigations best match your resources and interests. Our Phenology and Herbivory curriculum has moved to the Teaching Materials dropdown.

Join Us!

You can join this experiment at any timeThe data you gather will be most helpful if you gather them at the same site multiple times during the growing season, and for multiple years. However, a single set of observations at a site can still provide useful data, such as the relationship between the relative phenology of a plant and its interactions with invertebrates, especially if there are many replicates at the site.

For this experiment, protocols were created in order to guide researchers and data collectors through adequate practices as they gather data. The protocols give detailed step by step procedures. Following these protocols helps maintain the reliability of your measurements and hence the quality of the data and the research. You can find the specific project protocols here. We also have training videos for each protocol, so you can learn and practice important skills before going out into the field!

All your gathered data can be submitted here for processing and feedback.

WARNING: Please be sure to only collect data where you feel safe and have permission to work. If you have a severe bee allergy, consider an alternative form of participation.

Project Breakdown

ProjectProject GoalsOptimal SiteTime CommitmentMaterialsTraining Videos
1. Phenology and Herbivory (pairs well with #3)• Investigate the relationship between phenology of milkweed and the risk of herbivory by insects that eat them.
• Understand how the abundance and composition of the herbivore community on milkweed changes across space and time.
Any existing population of milkweed.• About 10-15 minutes per plant for 3-30 plants total.

• Suggested frequency of observations: at least every 14 days for smaller sites; at least 5 times per season at larger sites.
• One or more milkweed populations
• Phenology and Herbivory Guide
• Data sheet #1
• 1, 2
• 3.1, 3.2, 3.3
• 3.4 contains optional measurements for this project
• 4
2. Herbivory Bioassay

(Protocol in development)
• Track the risk of herbivory, or how much of the plants insects eat, across space.
• Know what kinds of creatures are eating milkweed plants in different regions.
A location to position potted milkweed, ideally one that is within view of milkweed, exposed to insects and will not be disturbed by people and vehicles (i.e. lawnmowers).• Preparation: Seed cold stratification and germination can take 2-3 months of minimal care and attention.

• Experiment: 3-10 days.

• Suggested frequency: 3x per year.
• A ruler or meter stick
• Milkweed seeds
• Small pots
• Data sheet #2
• 1, 2
• 3.1, 3.4
• 4
3. Pollinators (pairs well with #1)• Determine how the developmental state of the milkweed and its phenology affect its probability of pollination.
• Understand how the abundance and composition of the pollinator community on milkweed changes across space and time.
Any existing population of milkweed.• Protocol 1: ~4-5 minutes per plant for 3-30 plants.

• Protocol 2: Up to 10 minutes per site.

• Suggested frequency of observations: weekly during flowering.
• A population of flowering milkweed
• A camera
• Data sheet #3
• 1, 2
• 3.2
• 4
• 5
4. Seed Collection• Understand how the phenology of populations differ from each other genetically by growing plants from different places in a common garden.Any naturally existing population (remnant prairie or naturally colonized sites like old fields or roadsides) of common milkweed where you have permission to collect seed pods.• Completing Phenology and Herbivory protocol: about 10-15 minutes per plant for 5 plants total.

• Seed processing: 30-45 minutes for 5 plants total.

• Suggested frequency: once during Fall.
• 5+ paper lunch bags
• 5+ Ziploc bags
• Site Data Form
• Data sheet #1
• 1, 2
• 6

Consider Sharing Pictures and Videos From the Field to Improve Reliability and Remote Teaching Opportunities!

Two of our goals for MAREN are improving citizen science data reliability and expanding our protocol and data accessibility to open up remote teaching opportunities. Both of these goals entail careful documentation of observed sites, copies or scans of handwritten data sheets, and a video bank of pre-gathered field observations for later analysis. We ask that you consider documenting your data collection visually per the instructions in the protocols and upload your results as follows:

• Images of your site(s) should be uploaded when prompted within the Site Data Form.

Data Sheet pictures/scans should be uploaded within the specific project form you fill out.

• If you complete a multi-plant data sheet, your handwritten copy only needs to be uploaded once with the first plant sample form you submit.

• If you complete a single-plant data sheet for each sample, your respective handwritten copies should be uploaded with each form you complete for the different samples.

• Pictures and videos of herbivores, pollinators, and single plant surveys should be uploaded to theField Media page in the Library. If you use some of the videos for remote data analysis, include those specific video links in the data form you submit! There are instructions for three different methods of media sharing on the ‘Field Media’ page!

Contribute Seeds to Our Network

We invite you to submit milkweed seeds from naturally occurring (not planted) populations to our collection. We accept seeds on an ongoing basis and use them to answer questions about geographic variation in milkweed.