The Bug Geek

Insects. Doing Science. Other awesome, geeky stuff.

Where and Whither the Monarch?

One phenomenon I can usually count on every late summer/autumn is a sudden swelling appearance of Monarch butterflies as they begin to make their long migratory journey southward for the winter.  During the summer, I see them flitting about in my garden, and spot the caterpillars munching away on their wild host plants (milkweed).

monarch male

Male Monarch butterfly in my garden in September 2011.

This summer, though…nada.  Nothing. Zip.

Honestly, I didn’t see a single caterpillar, and although I remember thinking I might have had a glimpse of one adult flying across my road in August, it seemed small and could easily have been a mimicking Viceroy.

It wasn’t until just a few days ago that I found this:

Monarch pinned

Monarch butterfly (Danaus plexippus)

I found it lying back-up in the middle of the rarely-used old gravel road where I take my dogs for walks.

It was sad and beautiful: starkly, vividly orange on top of the dirt and scattered brown leaves. It was also dead. I gathered it up carefully in my gloves and walked it home. I felt it would be a waste to leave it there to be stricken by the elements since there was no other insect life out that might otherwise scavenge the body. Frankly, I was quite shocked to see it there at all, given the cold weather and heavy overnight frosts we’ve been experiencing of late.

So now it’s on a pin. Other than a couple of scales scuffed off on the top edge of the right forewing, it’s in excellent shape overall – no tears or tattered wing edges. I’m not usually one to pin butterflies (I find spreading wings fussy – the scuffed scales on the left wing were my own clumsy fault), but the utter absence of Monarchs this year made me think that this one was worth preserving.

Any casual observer of wildlife has noticed that the number of Monarchs in Ontario/eastern Canada has been way down this year.  I just went to ebutterfly.ca, a great new citizen science initiative, and drew up some maps comparing the reported observations of Monarchs in Ontario from May-October in 2012, and in 2013.  The difference is pretty remarkable:

2012-2013 Monarch ebutterfly

Citizen science reports of Monarch butterflies (from http://www.ebutterfly.ca) in southeastern Ontario in 2012 (L) and 2013 (R). There are also a few points to the northwest on the 2012 map that aren’t shown here. You can click to embiggen.

I made sure to add my “dot” to this year’s map.

Researchers suggest that this big change is likely due to a combination of less-than-ideal climate and a lack of habitat, and therefore of host plants. Here in the north, we get the last round of breeding adults; generations of butterflies progressively make their way northward throughout the breeding season, starting way down in the southern US.  Although we’ve previously thought that breeding grounds in the central US were the most critical for their success, new research by a team at the University of Guelph suggests that the entire breeding range is actually quite important. These scientists feel confident that the population will rebound, though perhaps not to the same historically high numbers.

Labidomera clivicollis, a milkweed specialist leaf beetle

Labidomera clivicollis, a milkweed specialist leaf beetle

I live in a rural area with lots of old fields and unmanaged roadsides: perfect places for milkweed to grow and so perfect places to observe its characteristically-coloured red/orange-and-black insect fauna.

One interesting thing I observed this summer was an absolute gangbusters number of specialist milkweed leaf beetles, Labidomera clivicollis.

I usually see a couple of them here and there but the milkweeds were covered in them this summer. Perhaps they were doing better with reduced competition? I’d be curious to know if others elsewhere observed the same thing.

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17 responses to “Where and Whither the Monarch?

  1. Sean McCann November 11, 2013 at 9:30 AM

    Monarchs are one of my fave butterflies, although we have few of them here on the coast. I am sad to see that they have dropped off so dramatically, and I hope it is just a temporary setback. I am not sure what the numbers have been like in BC, as I have not been in any monarchy habitats this season.

  2. Painting Pundit November 11, 2013 at 11:34 AM

    They are so beautiful. I’m glad you were able to keep this one to show. I too, hope it is only a temporary setback.

  3. Sarah November 11, 2013 at 12:13 PM

    I briefly attempted to be a mail carrier early this month, and on my second day I was sent off to a strange little alley of houses with 1/2 addresses and a steep crooked walk that seemed almost private. I turned a corner and there was the biggest milkweed I have ever seen, COVERED with fluttering Monarchs – following a lack of them I had noticed and confirmed online months before.

    It was like discovering gold. I’ve never seen butterflies so concentrated outside of the dedicated atrium in Scottsdale, AZ. I couldn’t stop for long, but I do think about going back for photos (it’s mid-November in southern California, so naturally every day is 70F and sunny). I’ll head to the monitoring site now; thanks for the reminder!

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  5. Benjamin November 12, 2013 at 2:18 AM

    Is there data for monarchs in the region going back farther than 2012, and if so, have they ever been close to these lows and then rebounded?

  6. michaelmarlow November 17, 2013 at 3:57 PM

    I haven’t seen one monarch, larva or adult, this year in Massachusetts. Really disheartening, but hopefully they rebound next year. Very nice post, btw.

    • TGIQ November 19, 2013 at 5:20 AM

      This seems to be the narrative shared by so many of us in this region. I’m crossing my fingers that things look better in 2014, too. Thanks for the comment!

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  9. Jennie Upside Down November 18, 2013 at 5:47 PM

    When I was a little girl, and it really hasn’t been THAT long ago, I delighted in seeing the Monarch caterpillars. I’ve not seen one in a really long time. Not one. Not even a chrysalis. I saw one butterfly this year. I’ve noticed the decline over the past few years. It’s a shame.

  10. Xi December 3, 2013 at 3:00 AM

    This year has been bad for butterflies in general, not just monarchs. In contrast, 2012 was a spectacular year and many old butterfly records were broken. I too didn’t see much in terms of Monarchs this year, especially early on in the season. Toward the end though, I did see more Monarchs and even eggs on milkweed.

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