Narrowleaf Milkweed and the Beautiful Queen of the Waterworld

Asclepias lanceolata

Apocynaceae

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I spend more time than the average retiree wading in Florida depression marshes.  Messing around out there, a person notices some things.  It is easy to notice widely scattered bright spots of red flowers…Narrowleaf Milkweed rising above the other vegetation.   Another less-conspicuous observation is that far from shores pollinators become comparatively sparse. 

Narrowleaf Milkweed with baby Queen, by John Bradford

Those two observations are no doubt linked.  If you grow scattered and far from shores,  pollinators may be a problem.   And those limited pollinators need to find you, which is where those showy flower clusters pay off.  The pollinators also need to be strong fliers to cover the extended distances.

Queen by Donna Rogers

On the second point,  back in 2006 ecologists Derek Artz and Keith Waddington checked out exactly which long-distance visitors pollinate Narrowleaf Milkweed in South Florida.  The three marathon winners were:  Giant Swallowtail Butterflies, Phaon Crescent Butterflies, and Queen Butterflies.  Paper wasps go the distance too but were not great Milkweed pollen carriers.

NL Milkweed habitat

What about the famous linkage between Monarch Butterflies and Milkweeds? I’m not saying that Monarchs never use Narrowleaf Milkweed as larval hosts or as nectar plants, but they were at least not in the long-distance winner’s circle.   Monarchs and Narrowleaf Milkweed may have a slight mismatch with some limitations.  First of all, Narrowleaf Milkweed  is widely scattered and has skinny leaves, both points not optimal for the big voracious Monarch caterpillars that devour more productive crowded leafy Milkweeds.   The skimpy food supply of the shoestring leaves probably disfavor Monarch caterpillars which become cranky and mutually aggressive when food is in short supply.   A shoestring budget is no place for grumpy Monarch babies.  Also, Monarchs  make themselves toxic by ingesting poisons from the Milkweed the caterpillars eat.  But turns out Narrowleaf Milkweed doesn’t offer much bang for your buck.

Encountered in the Milkweed habitat. Hope they ain’t human.

Queen Butterflies are closely related to Monarchs, and differ in ways that might make them a better “fit” with Narrowleaf Milkweed.   Although Queen’s can take up poisons from Milkweeds, they are less likely too, so a relatively non-toxic Milkweed seems ok for them. They are a little smaller on average than Monarchs and may thus fare better on skinny and scattered larval hostplants.  Also, although Queens and Monarchs both favor as larval hosts Milkweeds and close relatives, Queens have broader hostplant tolerances and may thus be less dependent on a rich crop of Milkweed out in the challenging marsh.   The jury is still out somewhat,  but it may be  Queens and monarchs have some tendency at least proportionally to favor different Milkweeds.  More research needed for a verdict.