I’m a sucker for nature documentaries. (I blubbered all the way through March of the Penguins, but in my defense, I was pregnant at the time and I blame my weeping on the hormones).
There’s a scene in the BBC Life series, episode 9, in which monarch caterpillars literally drown in the sticky latex sap that oozes from the veins of the milkweed leaves on which they feed.
Monarch populations are declining dangerously and milkweed is the only plant a monarch caterpillar will eat. The caterpillar’s source of life…now instead its cause of death. A tragedy! The blubbering threatened to begin, and I wasn’t even pregnant this time.
Turns out that this is a defense mechanism of the plant, which could otherwise be obliterated by the sheer number of feeding caterpillars. Only one third of hatched caterpillars make it through the first day of life.
But those that survive figure out how to disarm the milkweed by draining the sap from the leaf’s main vein, clearing the way to feed. They consume the plant for days until they pupate. Newly-hatched monarch butterflies then feed on the milkweed’s nectar, pollinating as they move from flower to flower, ensuring the next generation of plants. The fates of both species are intertwined, and survival, as usual, has its costs.
I managed to hold back the waterworks for the rest of episode 9. But now I see milkweed in a whole new light.