That’s right–not only do monarchs need milkweed to survive, but some ecologists believe that milkweeds may rely on monarchs as well!
Bees such as bumble bees are extremely efficient and reliable pollinators, moving large amounts of pollen throughout their territory. Their heavy bodies and hairy legs are perfectly designed for slipping into a milkweed flower’s stigmatic slit and picking up a load of pollinia (pollen sacs), transferring them to a nearby flower. This ensures a lot of genetic diversity for the plants within the bee’s foraging range (about a mile).
Monarchs are also frequent visitors to milkweed flowers, but their long, smooth legs and tongues are rarely caught by pollinia as they flit, mainly unencumbered, from one blossom to the next.
However, those pollinia that do manage to hitch a ride on a monarch’s tarsus may soon find themselves in a very different neighborhood! A monarch may fly dozens of miles in a day, resulting in much longer-distance pollen dispersal. In his book “The Milkweed Lands”, author Eric Lee–Mader suggests that monarchs could act as “a kind of airborne river for genetic exchange”, improving the genetic diversity of milkweeds overall.
