A monarch tale

A recently unearthed transcript of the minutes of an ancient spitballing session of the animal life cycle design committee sheds new light on the bizarre hurdles placed before the monarch butterfly.

Committee member 1: You remember the time we designed the reproductive process for those freshwater mussels?

Committee member 2: You mean the one where the female had to wiggle a fleshy protuberance that mimicked something a fish of a particular species might like to eat and then, when it finally attracted an open-mouthed fish of that species, it hurled all those microscopic glochidia into the fish’s mouth and gills, where they grew until they eventually fell out, hopefully in a place suitable for continued growth?

Committee member 1: Yes, that’s the one. Well, I’ve got an idea for a species that makes that look simple and foolproof. Its life cycle has more convolutions than your brains combined. Let’s start with a charismatic black and orange butterfly, whose eggs hatch into a beautiful green, yellow and black caterpillar, which, after shedding its skin five times, transforms into a jewel-like green and gold chrysalis. And let’s confine its egg laying and caterpillar feeding to a specific plant; milk weed, for example.

Committee member 3: So far, so good. But that sounds like a life cycle typical of many insects.

Committee member 1: You’re right. Let’s throw in some parasites like the tachinid fly, whose larva burrow into the caterpillars and eats them alive from the inside out.

Committee member 2: Ick. I see where you’re going with this. Please continue.

Committee member 1: OK, but first cut me another line of that white stuff, and I’ll give you the kicker. Let’s say this butterfly, with a typical insect life span of about 45 days, has to migrate to a warmer climate each fall. And not just to any place with a suitably warm winter climate but to a specific few hectares in a remote Mexican mountain range.

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Committee member 2: Now we’re getting somewhere So how does a frail- and flimsy-looking insect with a six-week life span fly 2,000 or more miles? If it makes 50 miles a day, best case scenario, that’s at least a six-week journey.

Committee member 3: And while we’re at it, how does it even know when to leave and how to get there? As some backwoods newspaper columnist might one day say, you could give him a new car, military-grade GPS, unlimited U.S. and Mexican currency, three well-armed former Navy Seals bodyguards and the rest of his life to get there and he still couldn’t find the spot.

Committee member 1: Cut me another line, please, and I’ll give you the icing on the cake. Let’s say some butterflies actually make it to their winter hideaway. Maybe by accident. Maybe they develop some kind of circadian clock in their tiny brains. Who knows? But if so, how are they, with their six-week life spans, going to get back to their breeding grounds in the Midwest and Canada? Are they going to run it like a relay race, with one generation handing the baton to the next?

Committee member 2: I think you’ve done it. The obstacles you describe would be extremely difficult for even the most highly motivated and adaptable organism to survive.

Committee member 1: Well, unless you consider it overkill, we could, just to be on the safe side, throw in a warming climate and the widespread adoption of chemicals to kill insects and the plants they need to survive.