The Value of Cow Parsnip for Insects in Alaska is meant to illustrate how certain plants attract a wide variety of insects to feed on their nectar and pollen.
The Cow Parsnip is considered a "generalist" flower that attracts several species of insects.
These types of flowers are (from the book Pollination and Floral Ecology by Pat Willmer, 2011 by Princeton University Press}.
open accessible flowers, bowl shaped or flat;
small or medium-sized flowers (very small examples often grouped together as inflorescences);
commonly white, cream, or yellow-green in color;
mild to moderate scents, fruity or musty but not unattractive;
highly accessible pollen, often in large-quantities;
exposed nectar, occurring at low volume and usually high concentration.
This seems to fit the Cow Parsnip (Heracleum lanatum) perfectly.
In watching the insects that come to various flowers I am always amazed at how many visit the Cow Parsnips. Even on cool rainy days.
For interesting information about this plant look at Harvey JA, Gols R, Smith B, Ode PJ. Invasive moth facilitates use of a native food plant by other native and invasive arthropods. Ecological Research. 2019;34:659–666 /sites/default/files/1440-1703.12035.pdf
