Nectar feast

Here it is almost mid-August already, and the insects seem to have just discovered all the milkweed in the backyard.  The hummingbirds prefer the orange-colored Butterfly Weed, but the butterflies, bees, wasps, and hover flies (syrphids) are buzzing the swamp milkweed.

Each flower head seems to be covered with three or four Great Black Wasps, some of which are enormous 2-inch individuals.  Fearsome looking!

Each flower head seems to be covered with three or four Great Black Wasps, some of which are enormous. 

Great Black Wasps are so large and fly so erratically around the backyard, it makes you want to keep your distance.  This wasp is one of the cicada killers that capture and paralyze their prey before laying a single egg on it in an underground nest.  You can read more about them in an earlier post.

One of the larger ones -- almost 2 inches long.

One of the larger ones — almost 2 inches long.

Each milkweed flower has 5 hoods into which an insect could dip its tongue for nectar.  The Great Black Wasp foraging technique seemed completely random as they probed flowers in a very non-systematic way.  However, their foraging efforts were complicated by individuals continually buzzing each other. causing them to move to another flower head before they had finished probing all the flowers.

With their extremely long legs spread out over the entire flower head, Great Black Wasps come into contact with a number of the pollen sacs (pollinia) on the milkweed flowers, managing to remove them to carry to other flowers.  The left middle leg of the wasp in the photo below has three sets of pollinia attached.

You can see yellow pollina attached to the legs of the Great Black Wasp.  A Yellow Jacket

A Yellow Jacket was furiously beating its wings trying to get its leg out of the slot in the milkweed flower where the pollinia are supposed to be inserted.  You can read more about how milkweed flowers are pollinated in an earlier post (click here).

In contrast, this little Aphrodite Fritillary sat on one flower head for several minutes turning slowly almost full circle, as it systematically sampled each hood of each flower.  When wasps or bumblebees approached that set of flowers, the butterfly simply flicked its wings a couple of times, and the encroaching insect moved off.

This Aphrodite Fritillary looks like it might have been grabbed by birds or dragonflies more than once.

This Aphrodite Fritillary looks like it might have been grabbed by birds or dragonflies more than once.

It looks like the butterfly has one foot as well as its proboscis in the hood of the milkweed flower.  Butterflies have taste receptors on their feet, so maybe it is sampling the nectar quality?

It looks like the butterfly has one foot as well as its proboscis in the hood of the milkweed flower. Butterflies have taste receptors on their feet, so maybe it is sampling the nectar quality?

Milkweed plants provide a lot of nectar for a wide variety of insects, making the garden much more attractive to all sorts of wildlife.  The flowers are brightly colored, and some have a pleasant odor. Their one drawback is their tendency to plant themselves everywhere!

13 thoughts on “Nectar feast

  1. Beautiful pictures. I really need to get my macro lens on. I had an unexpected visitor to our butterfly weed today – a giant swallowtail. I didn’t think they came this far north, but here are a few pictures to prove it. I guess climate change may be expanding their range. It was only interested in the butterfly weed and never visited another flower.

    • Fantastic! Thanks for the link. I have not seen a Giant Swallowtail BF. By the way, I don’t have a macro lens (yet). I took these with the 400 mm telephoto, and was glad to be far away from those giant black beasts of a wasp!

      • Today I watched one of those enormous wasps take down a katydid easily half again her size. The katydid never stood a chance – and the paralysis seemed to set in quickly. Yeah, it was a little terrifying.

  2. Fascinating post Sue, and great pictures too. Especially the ones of the wasps. I didn’t know that butterflies have taste receptors on their feet, how was that proven? It must have required some intricate experimental design.

    • There seems to be a critical size of insect for which the milkweed pollina system is tricky. They are small enough to get their Farsi into the slot, but not big enough or strong enough to pull their leg out when it has slipped into the slot. Honeybees unfortunately are just that size, and are the ones I most often see stuck. Usually if they buzz around and change their position on the flower, they can escape.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s