DNA analyses on Amblyomma americanum adults

Since my last blog post, I have been conducting analyses on adult ticks to check for zoonotic pathogens. Specifically, I have been testing for Ehrlichia chaffeensis, which can be transmitted to humans. To conduct the DNA analyses, I first start by identifying the adult ticks and cutting each on in half using a sterile razor blade. Each tick is placed in a sterile tube for DNA extraction. Following a series of elutions, a polymerase chain reaction is carried out to amplify the DNA. After the reaction is complete, gel electrophoresis is completed to determine the presence or absence of Ehrlichia chaffeensis. 

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Using Herbivory Blocks to Test Herbivory’s Effect on Sexual Reproduction of the Common Milkweed

For the final leg of the field research, we embarked on another ambitious task.  Throughout the observations, we did not see any red milkweed beetles with pollinia attached, so they probably are not acting as pollinators.  However, that is not the only way these beetles could affect sexual reproduction.  In order for the milkweed to engage in procreation, the plant must attract pollinators to remove the pollinia and take the pollinia to pollinate another milkweed.  That is why most plants, including milkweed, produce nectar.  There is a slight wrinkle in milkweed however; they are poisonous.  They produce cardenolides to resist herbivory.  Those chemicals are found throughout the plant, from the seeds to the leaves to the flowers.  That means herbivory by the red milkweed beetles could ramp up the milkweeds cardenolide production, which could drive off pollinators.  If that were true, herbivory could lead to decreased pollination.

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