Milkweed Connectedness Update 1:

My original plan was to use common Milkweed as a study system to understand the impact of clonality and group survival. By intentionally adding a pathogen, such as an herbicide, the spread of the negative effects can be witnessed in a clonally connected plant. The goal of this experiment is to see how far the pathogens travel in a patch, how long it takes for other plants to die, and if there is any preferential sharing. For instance, sometimes younger plants are favored in sharing. Herbicide will be used as a proxy for connectedness and physiological integration. 

[Read more…]

Herbicide Transfer through Clonal Milkweed

In this study I propose to use common Milkweed as a study system to understand the impact of clonality and group survival. By intentionally adding a pathogen, such as an herbicide, the spread of the negative effects can be witnessed in a clonally connected plant. The goal of this experiment is to see how far the pathogens travel in a patch, how long it takes for other plants to die, and if there is any preferential sharing.

[Read more…]

The Effect of Novel Animal Models on the Sexual Reproductive Pathways of Asclepias syriaca

One of the most beloved insect species alive today is the Danaus plexippus, or the monarch butterfly.  Ominously, they have seen concerning population declines which have been strongly linked to a decline in milkweed, specifically Asclepias syriaca (Common Milkweed) populations, the host plant of the Monarch caterpillar.  Between 1999 and 2010, the milkweed and monarch populations decreased by 58% and 81% respectively (Pleasants and Oberhauser 2012), highlighting the need for conservation.  While we know a great deal about monarch and milkweed interactions, we know comparatively less about the milkweed interactions with other specialist insects.  In addition, much of the literature deals with the milkweed’s ability to propagate itself through asexual budding, while the sexual pathways necessary for long term survival remains receive less attention.  By learning more about the milkweed’s sexual pathways, conservation efforts can be more targeted to increasing genetic diversity more efficiently, raising the likelihood that milkweeds can make a comeback.

[Read more…]

They Heard It Through the Grapevine: How Asclepias syriaca Communicates

Asclepias syriaca, or common milkweed, is a tall, herbaceous plant that reproduces both sexually, through pollination, and asexually, through producing multiple shoots from a single root system. It has strong chemical and physical defenses against herbivory, and when the plant senses that tissue is being disrupted by insects, it accordingly increases its production of latex (a gummy liquid) and cardenolides (toxic compounds). Previous studies have shown that other clonal plants with shoot or root connections are able to share resources such as water and nutrients between stalks. My research will investigate whether stalks of A. syriaca experiencing herbivory can share the signals that induce increased defenses with their clonal relatives; in effect, can milkweed stems “talk” to their fellow clones to warn them about present dangers?

[Read more…]

Conclusion

The goal for this summer was to have sampling, DNA extraction, Polymerase Chain Reaction (PCR), and fragment analysis sent off (to be later analyzed) completed on all 400 of the subsamples. Sampling and DNA extraction were finished. PCR unfortunately was not, delaying fragment analysis as well. Though the PCR protocol was developed during spring semester of 2017, new primers and a host of other problems made this step tricky. The first batch sent off for analysis came back blank, requiring adjusting of the protocol and the second had nebulous results. A delay in shipment meant that only 3 of the 7 primers were available for much of the summer. However, all extractions were completed successfully, and in the last remaining weeks of July, PCR was done on all 400 of the plants for 3 of the primers. All PCR products were shipped off for fragment analysis. Training began on using a fragment analysis software, so once results do come back, analysis will be smoother.

[Read more…]