So Many Choices!

It was a very busy day in the lab today! Class started off with some opening remarks from Louie. First, Louie and Elizabeth will be doing individual meetings with everyone in two weeks to check in on how the class is going. Be sure to fill out the Doodle poll on Slack to schedule a meeting time! Second, our batch of post-pocket spods were screened by Elizabeth before class, and it doesn’t look like they’ve been parasitized.

MC Zhizhou kicked off today’s agenda by splitting the class into two teams: 1) a spod-rehoming squad and 2) a Choice experiment protocol revision squad.  The spod-rehoming squad worked hard to transfer our newly-hatched spods into new homes with the batch of diet made on Thursday (Thanks Elizabeth, Zhizhou, Vivienne, and Sarah for making the diet!).  The protocol revision squad spent some time chatting about the issues we encountered last Friday with our current Choice experiment set-up.  The protocol team then created a list of potential experimental designs that could solve some of these issues.  We came up with several creative solutions to improve our Choice experiment, including:

  • Feeding stations to incentivize a choice
  • Switching the material of the container
  • Reduce the size of the container
  • Use fluorescent powder to track where our Tachinid has landed
  • Create an apparatus to force our Tachinid to make a choice

The majority of class afterwards was spent testing some of the designs on this list.  We got creative with our experiment protocols by using honey-coated microscope cover slips and fluorescent powder (which worked pretty well!). We also tested our Choice experiments using different materials, including Petri dishes (which did not work out well), plastic Ziploc containers, and a special arena made from clear plastic and a glass/Pyrex ring Louie found in his lab. We tried running Choice experiments both inside and outside the classroom and took note of how many landings we observed. After a while we were running low on flies, so Louie led a small group to go catch some more!

Trying to look underneath our upside-down Tachinid arena apparatus to see what our fly friend was doing!

After our various tests, we reconvened for a debrief of the day’s activities. From our potential Choice experiment options, we found that the honey trial worked best inside the classroom. The Tachinid arena trial was overall pretty successful, but there is an issue of whether we can create more of these arenas. The best option we tested seemed to be the plastic Ziploc containers, which had the highest rate of landing when the trial was conducted outside. The fluorescent powder seemed to be a promising option as well, but we will likely need more data before choosing this. At the moment, the Ziploc containers are our best bet due to the success we saw today and the ease and portability of the apparatus. Elizabeth has offered to go buy some more containers so we can start mass-producing Choice experiment containers. (Thanks Elizabeth!) We also chatted about the possibility of automating the observation process for our Choice experiments, which is a good idea especially if Tachinid landing behavior occurs over a long time frame. Louie has a bunch of time lapse cameras, which seem to be a good option for this!

We ended the day by discussing our plans for the next few weeks! Louie brought up a good plan of using horseflies for our Choice experiments, since they have a known aversion to stripes. So, the plan for next Friday is to set up traps at the UC Davis Equestrian Center to see if we can catch horseflies for testing. Elizabeth also mentioned that potentially there are Tachinids in Bodega, and we could have some woolly bears (hopefully with Tachinids in them) brought back to Davis next Friday!

The weather is starting to get warmer, so it seems to be about that time of year for monarchs! This means we all need to be on the lookout for monarch adults and eggs while we’re out and about! We also need to start thinking about the logistics of building a monarch colony, including what to do with the milkweed, where we are going to house the monarchs, and the timeline of rearing the caterpillars. A few people in the class were planning a Tachinid-hunting quest this weekend, which would be a great time to also go Monarch-hunting! They’ll be hitting up wild milkweed spots in Davis to see how many monarch adults and eggs are present!

Plan for Next Tuesday:

To prep for Friday’s horsefly expedition, we should figure out the best way to assemble a bunch of Choice experiment apparatuses using our Ziploc containers. We should also discuss how the Monarch/Tachinid quest went this weekend and possibly set up a plan for our soon-to-be-incoming monarch population!

See y’all next Tuesday and good luck this weekend to our Monarch/Tachinid questing crew!

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