Meeting the Lighting Expert: Eric


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Spiders caught in our pit fall traps!

Now that we have all been able to have more experience with our system we wanted to come back to our questions and reassess them. It was a great exercise in learning how to effectively and concisely communicate our research question. We were also able to check in about our observations from our weekend preliminary experiments. Although there didn’t seem to be any immediate difference between lit and unlit we did catch quite a few spiders and found some interesting results. We decided that in the future we really need to use “legit” lights and that it would be best to set up tomato cages in areas where there is a wind break. We also realized that we might need to redesign our experimental set up to entice orb weaving spiders. Asia had some interesting construction ideas such as covering part of the cage to get spiders to climb up the tomato cage

Meeting with Eric:

  • Eric hasn’t necessarily seen spiders but has noticed that other organisms such as tree frogs take advantage of this resource.
  • It’s unknown if increasing the density of herbivores will increase ovipositing on nearby plants which might then increase herbivores. ( is this too big of an assumption?)
  • Detura might be a good option for plant if we grow it in the lab not outside
  • Eric suggests using Alfalfa
  • Katydid and tree crickets might be good herbivores to look into
  • Plutella and Brassica might be a good system to look into to understand herbivory and light effects.
  • An interesting pilot would be to check if we can find Plutella near and far from street lights.
  • Surveying spiders directly might be helpful
  • If we are to measure herbivory effect it will be important to consider all the predators in the system not just spiders.
  • Extensive piloting is recommended


  • Is it better to expand our organisms of interest to more than just spiders. Should we be looking at predators as a whole
  • Is the attractive power of a light limited to right next to the light?
  • Path lights seem like a good option for field experiments. They are cheap and close to the ground.
  • It will be important to understand if light intensity has an effect on spider and prey density.
  • Relative brightness: the first light in a dark area might have a larger effect then in urban areas where light is very pervasive.
  • We will ask Ivana Li from BIS 2B for some brassica plants to do an initial pilot study.

    Louie’s experimental plan idea

    We talked through what we expect from each of these treatments for all of the arthropod communities of interest (spiders, herbivores, prey and other predators). We were all a little “weirded” out by our assumption that light would increase herbivory by increasing herbivore oviposition and therefore increasing future larvae. Marshall brought up the fact that 24hour lighting might also change the circadian rhythm of plants. When their defense cycle is different than their herbivore it might expose them to more herbivores. This exercise helped us talk through our expectations for each trophic level we were investigating. It was great to do hypothesis building as an entire group.


    Our predictions and hypothesis

To do before next week:

  • Light Group: What kinds of light are affordable and useful for our project?
    • Group Membership: Rachel, Emily,  and John
  • Botany Group:What kinds of plants might be good for our project? How do would we plant them/germinate them?
    • Group Membership: Keatyn, Robert, Cameron, and Deniss
  • Pilot and Observation Group: How is community composition and density different at different locations and artificial lights?
    • Group Membership: Miles, Ashley, Asia, Darian, Kyle, and Amy
  • For everyone: Start brainstorming how to test our evolution question? Would this be in the lab? How would it work with spiders having such large ranges?

Agenda 3/2/17

1:40-3pm Small group meetings, time to work, visit the field, etc

3:00-4:30 Large group check in, what do our groups need to move forward with our respective tasks?

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