...and recently someone asked me why bees work wind-pollinated flowers, such as willow. That had me stumped, but I think the argument goes as follows. Wind-pollinated trees typically have catkin-shape male flowers which produce enormous amounts of light and dry pollen that is not particularly nutritious as far as bees are concerned. The female flowers carry sticky stigmas which catch pollen grains which are blown in their direction. It's a bit hit-and-miss, but nobody could deny that it has been a successful strategy for millions of years (billions even? - I need to check). The willow family changed over to partial insect-pollination by investing energy in creating attractive pollen (sweet, protein-packed, colourful and aromatic) while retaining the typical wind-pollinated flower shape.
It's not only the willows that have adopted this tactic, the Acers have as well, such as our sycamore and plane. So far so good. Now, let's go back to our cryptic box elder. According to D. M. van Gelderen (Maples Of The World), Acer negundo is in the process of changing its mind anthropomorphically speaking. Having started out as wind-pollinated plant, it changed to insect-pollination and now seems to be going back to wind. How strange is that? What environmental pressures is the species responding to?
|Mason bee and leaf cutter cocoons|
|Cocoons in tubes for over winter storage in fridge|