Let's face it, it has not been a lot of fun to monitor monarch eggs and larvae in 2013. In fact, just sitting down to write this article made me a little depressed, so I'm going to walk into my yard (it's August 24, 2013) and see if I can cheer myself up by seeing some monarchs.......... I'm back, and I saw two, one on blazing star and one on ironweed. So, they're out there, and I have the pictures to prove it.
Just what do the numbers show? While we wait until the end of the season when everyone has entered all of their data to do careful analyses, I pulled up the data from Minnesota, where 33 sites are being monitored this summer. The data from other northern states look pretty much the same. These sites range from the Gunflint Trail way up in northeastern MN, where David MacLean has been monitoring a patch of swamp milkweed since 2010 (David saw no eggs or larvae at all in 2013), to New London-Spicer in west-central MN where Laura Molenaar and many students have been monitoring milkweed patches since 2004 (they saw a few monarchs this year), to many sites in the Minneapolis-St Paul metro area (my daughters and I have monitored our yard since 2002, and on my best day this year I found 20 eggs on about 135 plants).
The graph below shows egg densities (as eggs per milkweed plant monitored, so a value of 0.20 means that there were 20 eggs on 100 plants, and value of 0.02 means there were 2 eggs on 100 plants).
- 2011 was a "normal" year (see the blue line on the graph). The monarchs came back in late May, had a May peak of about 0.27 eggs per milkweed, and a July peak of about 0.16 eggs per milkweed (about 16 per 100 plants).
- 2012 was unusual (see the red line on the graph); remember our early spring? The monarchs came back about a month early in very high numbers. Note the peak of about 0.60 eggs per milkweed in early May. But then the population crashed, and our early July peak was only about 0.10 eggs per milkweed. The crash was probably due to a combination of the heat and lack of rain, which was hard on the milkweed and the monarchs, and high numbers of predators.
- 2013 has been terrible from the start (see the green line on the graph). After the lowest overwintering population ever, the monarchs came back late, and the numbers have stayed low. Our peak this summer was during the week of July 22, when the egg density was 0.028; that means people are seeing fewer than 3 eggs for every 100 plants they observe. The graph doesn't show caterpillar data (you can see these numbers online), but out of 14,313 times that MN MLMP observers have looked at a milkweed plant this summer, they have only seen 96 caterpillars, and only 14 5th instars.
- First, plant milkweed and nectar sources. If you have an MLMP site, you're probably already doing this, but consider adding more plants if possible. Monarchs have lost a lot of habitat with the advent of herbicide-tolerant crops and expanding human habitation.
- Second, educate others and advocate for monarch conservation. For example, you can register your site as a monarch Waystation, and put up a sign that recognizes that registration (see http://monarchwatch.org/waystations/ for more info). You can talk to friends and neighbors, ask local or county land managers to do things like avoid mowing ditches when monarch larvae might be present, or advocate limiting insecticide spraying at the local, state or national level.
- Third, get involved in a monarch citizen science program and contribute data that will help us manage monarchs more effectively. The Monarch Larva Monitoring Project, Journey North, and Project Monarch Health are all good possibilities, and all have websites with clear directions.
- Finally, donate money to conservation organizations like the Monarch Butterfly Fund or the Monarch Joint Venture. These organizations work on monarch conservation in Mexico and the US, respectively.
It's my hope that the MLMP does not become a tool that simply records the demise of monarchs. Rather, it should be a tool that energizes people to do what they can, and helps us understand the best ways to help monarchs survive in a changing world.
University of Minnesota Monarch Lab