Data Analysis Cont.

It is unbelievable that the research period is just about over already! The past 8 weeks have flown by. However, progress with data analysis is slowing down. I have successfully cleaned all my insect data and calculated several diversity measures for each site and transect using R for Statistical Analysis. Using R was not as terribly daunting as I was anticipating though it was frustrating at times. The feeling of triumph when a code would finally work made the frustration well worth it! Altogether, I have calculated abundance, species richness, Simpson’s diversity index, Chao’s species estimator, Pielou’s evenness measure, and rarefaction curves for each data site. I am now working on turning my calculations into visuals. I can preliminarily judge the differing diversities of the sites, but will also be running statistical tests on the data to see which sites are overall “more diverse”.  I will obtain the patch sizes for each transect to complete my analysis.

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Time to get statty

Most of us in the lab have officially finished our field work with both milkweed and insects! For the remainder of the summer I will be going out into our nearby field site 1-2 times per week to collect some final data on insects. I have read that different types of milkweed herbivores will be emerging late in July (around this time). Our nearby site has relatively low insect density in general so I am unsure how much insect activity I will actually record, but it will be interesting to see! I am hoping to collect more samples for my insect teaching collection though I am doubtful that Yorktown has enough individuals for collection.

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Ridin’ on the milkweed bus

June milkweed fieldwork is thoroughly underway! We have been collecting data for a couple weeks now and have almost collected data on every transect. We ended up abandoning one transect at New Quarter Park. However, we have since visited and collected data on our five transects at Yorktown Battlefield, seven at Blandy Experimental Farm, and two at Sky Meadows State Park. We are winding down on plant data collection this weekend with four transects at Prequile National Wildlife Refuge. We began at Blandy where we learned methods for measuring and recording data. Though I was slow both at measuring and recording at first, after hundreds of milkweed plants I have gotten more proficient with the meter stick, calipers, and rugged handheld field PCs. When we return from Presquile next week, several of us in the milkweed crew will go back to Blandy to collect data for our individual research questions.

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Milkweed Preparation

This week marked the beginning of my milkweed adventures and what I’m sure will become a beautiful relationship with milkweed herbivores. I kicked off the research period by becoming van certified which will become important later in the summer when taking day trips to our nearby but off-campus sites at New Quarter Park and Yorktown Battlefield. We (the milkweed researchers in the Plant Ecology lab) began by revisiting our research questions, establishing summer goals, and designing our experimental set-ups. We have also spent time finding useful literature on our particular subjects that will provide information and potential methods for our projects. I have finally come across papers on crab spiders and milkweed after months of searching which is very exciting for my potential research involving spiders as predators on milkweed. Aside from preparatory lab work, we have inspected our nearby field sites to identify transects from last year. At our first site we were unable to find our tagged plants and anticipate potential problems at this site. However, there is still hope at finding our plants. If not, we know of other prospective sites that we can scout out and perhaps set-up for study. We saw only a couple insects on the milkweed in the field but many spiders were out and about despite the lower temperature so I am looking forward to seeing more! Next week I will try out different methods for insect collection, potentially utilizing sweep nets in place of manual collection.  I am anticipating the coming weeks to be filled with sweat, fun new technology, and hopefully many insects!

Milkweed and Herbivores!

My name is Rachel Cook and I am a sophomore in Dr. Harmony Dalgleish’s plant ecology lab. Milkweed is an exciting plant because it thrives in areas categorized as disturbed, has unique defenses against herbivory, and in turn has a specialized insect community. In an attempt to understand plant-insect interactions with milkweed and its insect community, I will be doing research to quantify insect diversity and interactions. This summer I will be examining how milkweed patch dynamics affect (or do not affect) insect diversity, particularly focusing on herbivores. I expect to find lower quantities of herbivores in smaller, less dense patches of milkweed and higher quantities in larger, more dense patches. However, my expectations could be reversed as insects may be more dispersed within denser patches. While patch dynamics and insect diversity is the major aim of my research, my deeper interest is in interactions between insect predators and their prey. During the course of my research, I will also gather information on how milkweed patch size and density affects predator-prey dynamics and how these dynamics in turn affect milkweed. I am particularly examining spiders and how the presence of spiders, a major predator in any insect community, affect the insect community. I hope to find significant information to conduct further research with spiders in the future.