national pollinator week: what’s on your flowers?

June 21, 2008

in Insects,Natural history

June 22-28 is the 2nd Annual National Pollinator Week, an event sponsored by the Pollinator Partnership. The fact that so many of the world’s pollinators are in deep trouble is finally starting to make the news. There are, of course, many bats, birds, and other animals that perform pollination services. Aside from declines in those populations, people are hearing more about the problems with our most familiar domestic insect pollinator, the honey bee. There is a real crisis, too, with wild insect pollinators, especially bumblebees.

Reasons for declines in these pollinators include habitat loss/destruction/degradation and introduced pathogens and parasites. Pesticides are also a likely culprit, but unmanaged wild pollinators are relatively poorly studied in this regard, and there is a lack of historical baseline data to fully assess impacts of chemicals on various species. Another worry is possible loss of synchrony with blooming plants due to climate change.

Some great resources on pollinators and their conservation:

People often forget that flies are important pollinators. Regular Bootstrap readers will recall that last year I began my “Diptera in the Yard” project, and that I think many species of flies are remarkably cool. In honor of National Pollinator Week, I thought I’d do another photo essay on flies, featuring some that perform pollination duties.

The family Syrphidae is huge and includes many lifestyles, but at least 1000 are known to be pollinators. You have most likely seen “flower flies” like this Helophilus fasciatus. This one is a female — her eyes don’t touch at the top. Male flies have bigger eyes that generally meet.

These horny little flies are also Syrphids, Toxomerus marginatus. Like most Syrphids, the larvae are predaceous; Toxomerus larvae feed on aphids or other small insects.

Most of the really good bee and wasp mimics are Syrphids (the top photo is of a bumblebee mimic, Mallota; there is another photo in my other post). However, the Bombyliidae are known as the bee flies. They are typically hairy and have a long proboscis. The most familiar bee fly is Bombylius major. Here are a couple of other bee flies. The first is this whimsical fly in the genus Geron.

And this is Aldrichia ehrmanii, a species which was recently very common in my area.

Tachinid flies are the ones that lay their eggs on butterfly or moth caterpillars. The larvae burrow into the caterpillar, feed on the host, and drill their way out when ready to pupate, killing the caterpillar. About 2000 species are known to be pollinators (the adults, that is). For example, the only place I’ve seen seen these Archytes tachinids is on flowers.

So starting this week, stop and take a look at the diversity of pollinators in your garden, your nearby park, and the empty lot down the street, and give them a little more appreciation for what they do and their role in the ecosystem.

Hey — what’s on your flowers?


Aydin June 24, 2008 at 2:35 pm

I've got carpenter bees on my flowers. They are also ruining my fences…

lorri July 6, 2008 at 10:44 pm

Not a timely reply exactly, sorry, but I have bees quite often hovering around the clusters of flowers on my green onion plants. These are the kind of long, skinny onions you use in salads. I like to plant the cut-off onion tops and let them grow (rather than digging them back up to eat), and bees really seem to like the flowers.

The only other flowers I've seen bees around much lately are the flowers on the crape myrtle in the front yard.

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