This week went pretty well, but there was one major mix up in the field. The team that was assigned to 355-388 got confused and accidentally did 358-374 plus 474-488. So that means that 375-388 didn’t get measured in Week 6 (bummer, that). The silver lining is that 474-488 actually got measured twice, so we now have a chance to see how comparable the two sets of measurements are. Check it out:
These two figures tell me that the two sets of measurements were pretty similar, though not exactly the same. The measurements of stem area from 5/8 explained about 72% of the variation in the measurements of stem area from the same plants taken on 5/6 by a different observer team. We can probably live with that. The situation with stem length is even better – one set of observations explained 91% of the variation in the other, indicating that they are pretty similar. I guess the take-home message is please double-check your plant assignments to make sure you are measuring the correct plant each week!– messing this up means a lot of duplicated effort, and missing data. However, it is nice to know that these measurements are at least somewhat repeatable.
As for the data, here is the summary:
Looks like the pattern from last week is continuing – fewer caterpillars out there, but they are getting bigger. We can see the joint phenology of the caterpillars and the plants here:
I fixed a bug in the script which was plotting this phenology-ontogeny landscape (and a data entry error from Week 4) , so this is actually the first time this figure makes some sense. Right now, it is telling us that both the plants and the monarchs are getting bigger together. It’ll be interesting to compare this trajectory with 2015 at the end of this season.
Keep up the good work out there!