Insect Pollination: The Bees are Out Full Force

On my walks on May 2 & 3, one of the things that was hard to miss was the enormous amount of pollinator activity. I did not see any Apis spp. However, I did see a remarkably wide range of solitary bees, some syrphid flies, a single Bombus sp. queen, and of course the Bombylius major I posted about on Saturday. I also saw a single Pieris rapae (cabbage white butterfly) in the cemetery.

I am not able to identify all of the species that I have seen, but I took a number of photographs. It took a great deal of effort to get these shots. It's at times like this that I daydream about being able to buy a telephoto lens. How much easier it would be to take photos of pollinators if I didn't have to get my camera within a few inches of them!

Bombus sp. queen on Trillium grandiflorum

This Bombus sp queen was relatively easy to photograph, as she was rather sluggish. I discovered her pollinating some barely opened Trillium grandiflorum. She was so sluggish, in fact, that I actually managed to catch her in flight (shown below). She appeared to be focusing on the retrieval of nectar during the period I was observing her (note her empty pollen baskets).

Bombus queen in flight, just leaving Trillium grandiflorum after collecting nectar

This Bombus queen, however, was the only bee I didn't have to fight to get photos of this weekend. The rest were considerably faster and shyer.

One individual on whom I at least have a reasonably positive I.D. is this solitary bee visiting Scilla siberica; I believe this to be Andrena barbilabris.

Andrena barbilabris (?) on Scilla siberica

Another individual whom I believe I have identified reasonably reliably is this solitary bee, who I believe is Halictus ligatus, shown here visiting Tussilago farfara:

Halictus ligatus (?) on Tussilago farfara

There are a few more species I managed to photograph as well, but which I have been unable to identify as yet.

Unidentified solitary bee on T. farfara

Unidentified solitary bee on E. americanum

Unidentified solitary bee on S. siberica

There were many more than I managed to photograph over the weekend; I counted at least eight visibly distinct species of solitary bee pollinating the T. farfara, and there may well have been more depending on how visible and obvious the distinguishing characteristics of the species are; without a microscope and a specimen, it can be very difficult to judge. At any rate, the solitary bees especially were numerous and varied.

Colt's Foot - Tussilago farfara - Tussilage

On our walk on Sunday, E and I encountered Tussilago farfara (colt's foot, fr: tussilage) already in bloom, even though there was still snow on the ground in some places.

Tussilago farfara

T. farfara is a spring ephemeral, a plant which blooms in the brief period between snow melt and the closure of the forest canopy (the emergence of leaves on the trees), when there is light in the forest understory.

This plant is among the first bloomers this year. It often is, as it actually sets its flower buds in the fall prior to the season, a strategy which allows for the earliest possible emergence of flowers. Indeed, at this stage T. farfara does not have any leaves out. They will emerge only later, once the flowers have matured (and once the plant has been exposed to enough sunlight to produce new leaves). T. farfara is a rather unassuming plant later in the season, producing short, heart-shaped leaves in clusters.

Tussilago farfara inflorescence. Note the absence of leaves at this stage of the season.

The flowers are actually a cluster of florets, of which the long ones are fertile, and the ones in the inner disc are infertile. After pollination, they produce seeds which superficially resemble those of dandelions. They have a tuft of light material attached which assists in wind dispersal.

T. farfara is an introduced species in North America, being originally native to Europe. It was brought over as a medicinal plant, but note that we have since determined that it is a toxic plant which can cause serious liver damage. Some varieties without the toxic chemicals have been cultivated in Europe, but these are only in commercial settings; the wild plants are toxic.

This plant is also listed in the Ontario weed registry. It occurs primarily in disturbed areas, particularly along roads.