Week 12 Data: Bigger Milkweed, Bigger Monarch?

We were in an impressive heatwave last week – temperatures well above 100 F (38 C) for more than a week! The salwart GGI crew was out early to beat the heat on Monday, and collected these data:


We have data from 315 of 318 plants so far this week, and there might be a last minute mission to collect data from the 3 plants that were missed. This might partly explain the decline in the number of plants that were found to be alive, though it looks like we’ve probably somewhere in the ballpark of ca. 220 plants growing this year. That’s about 69% of the planted population, about 6% less than in previous years.

At first, it looks like both the plants and the caterpillars were bigger this week:


…but then I noticed that the “larvae per plant” and “larvae per week” metrics were both pretty low. A closer inspection of the data in R, shows why:



Unlike previous weeks, there was only one monarch caterpillar out there this last week. Is this part of a natural phenological cycle, a response to the heatwave, or something else?


Interestingly, it looks like the monarchs (eggs and caterpillar) observed this week were observed on smaller plants around the “bird entry park”.

On data entry, we noticed a couple groups forgot to write down their observation times, and one group that got a little disorganized on their datasheet, which caused them to enter data for the wrong plants. Kenya was able to catch these mistakes and correct them, but those are a couple data entry issues to look out for this week.

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