The class began with a short discussion of the agenda. We discussed the potential of using the big alfalfa field next to the black widow barn and the North Davis channel as caterpillar and tachinid collection sites. Louie mentioned that tachinids may be found on flowers. Since the population of flowering plants at this time of the year is limited, he suggested exploiting this opportunity to find tachinids potentially in aggregation. We also decided to transplant the milkweeds as they approach the optimal size for transplant. The discussion ended with some description of Lespesia archippivora identification. Besides the characters described in the literature, some have added that Lespesia spp. do not have overlapping wings at rest based on anecdotal observations (For more details, please refer to this glorious document that Annaliese compiled). Though, the details of flies can be difficult to determine in the field. As such, it was suggested that all chunky flies in general should be subjected to capture.
We splitted into three groups, each tackling a different set of tasks:
- Arboretum tachinid catching
- Milkweed transplant
- Alfalfa field and North Davis channel exploration
The arboretum group explored a small section of the Arboretum. We used nets to sweep flower bushes and grasses. Unfortunately, the abundance of flowers did not translate to an abundance of flies as we certainly caught more flowers than flies. It is likely that we are still too early for catching Tachinids. Though Elisabeth reassured us that we are still ahead of schedule nevertheless. In the end, we caught only around ten files in total. Jess caught 3~4 suspected tachinid on a rosemary bush.
The milkweed group went to orchard park to transplant the milkweeds we planted earlier into larger pots. A total of 192 pots were transplanted with many more to spare. For some reason the milkweeds were moved to a different greenhouse and will have to move to another greenhouse in a week.
The alfalfa group drove to the large alleged ‘alfalfa’ field next to the black widow barn. It turns out they were actually wheat. They reported minimal signs of tachinids and caterpillars. Before they left, they saw a guy spraying pesticides. The group then went to the North Davis channel. It was cold and wet. They saw many ‘leggy’ flies but no sign of tachinids.
The groups reunited about one hour before the class ends. Hoping to obtain more tachinids, we caged the newly caught suspected tachinids with Annabelle’s tomato hornworm. No activity was observed at the conclusion of the class.
We discussed the possibility of emailing John Stireman, but in the end decided not to because of several reasons:
- Result of tachinids may not be generalizable.
- We found partial answers to our questions
- It is likely that the stuff we are looking for is not know by any living soul. We may be the only expert on this.
- We can always keep the option in our back pocket
We then discussed the possibility of setting up the traps soon. Unfortunately, it appears that more wind and rain are still to come, thus making this unlikely. Louie mentioned that it will still take a while to obtain the beet armyworms and it would be useful to think about what we would do if we get a Lespesia archippivora right now. What would we rear it on?Tomato hornworm? Would we use it for experiment?
Plan for Tuesday in the order of importance:
- State the question and hypothesis of interest
- Write protocol and build data sheet (I’ll post a fake data set in excel and some analysis in a R script in Slack over the weekend)
- Theory discussion
- Build experiment apparatus?
PS. We will have class during the ENT 180 final exam slot