Pollinator Pit Stop

I took a break from my bike ride the other day to see what insects were visiting this patch of wildflowers.

Flowers that bloom late in the summer are often teeming with insects. This is an important time of year for them to stock up on pollen and nectar to help them or their offspring survive the long winter.
Many of the insects on flowers have black and yellow stripes, which make them easily mistaken for bees or wasps. This syrphid fly (Diptera: Syrphidae) for example, is a fly, not a wasp, and it couldn't sting you if it tried!

Syrphids are actually very beneficial insects in the garden. They lay their eggs near aphid colonies and when the syrphid larvae hatch out, they devour the aphids one after another.

Here is another fly that could be mistaken for a bee. This is a bombyliid fly or "bee fly" (Diptera: Bombyliidae).

Some members of this fly family are parasites of bees and wasps. They attack their hosts insects by flicking the eggs into their nests. The bombyliid eggs then hatch and the larva eats the host larva as well as the food that the host's mother provided for it in the nest. Its a pretty nasty strategy, but bombyliids are pollinators too, so they're not all bad.

Speaking of pollinators, there were honey bees visiting this flower patch as well.

Honey bees (Hymenoptera: Apidae) are the #1 insect pollinator of our food crops and they are also important for honey production.
Honey bees are not the only bees that pollinate our food crops though. There are hundreds of other bee species that help with the pollination.
This is a sweat bee or halictid bee (Hymenoptera: Halictidae).

They are called sweat bees because of their habit of landing on our skin to drink droplets of sweat. Many people find this irritating so they have a bit of a reputation as a nuisance, but they are important pollinators. They can sting people too, but will only do so in defense and their sting is fairly mild. Next time you have a sweat bee on your arm try just shooing it away rather than swatting it. Sweat bees come in a variety of shapes, sizes, and colors. The green metallic one above, is one of the largest ones in our area (Northeastern United States).
Here is a much smaller one on a goldenrod flower.

As you can see halictids tend to carry pollen on their hind legs. The pollen is held in place by tiny hairs on their legs. They are gathering pollen to take back to a nest where they form it into a ball for their offspring to feed off of while they grow. Halictids usually nest in burrows in the ground, sometimes in large groups. If you ever come across a cluster of tiny holes in the ground with sweat bees bees going in and out you may have found a colony of halictids.
Halictids are just one of the many important bee pollinators of our wild and cultivated plants. I will hopefully get to cover other groups in future posts. You can also follow this link to all of my previous posts about bees. Thanks for reading!

Knappy Dread

We were out picking blackberries the other day and came across some Spotted Knapweed (A.K.A. Star Thistle). This is a very controversial plant because it is an important nectar source for honey bees, but it is also an invasive species in parts of the world where it isn't native. Up close, the flowers are actually very pretty.

Unfortunately, the rest of the plant is not particularly attractive.  Here is what it looked like in our blackberry patch.

Usually, however, spotted knapweed is found in large patches where it has eliminated many of its competitors.
Large patches of knapweed can be a very important source of nectar for honey bees and many beekeepers depend on this plant for their livelihoods. The bees use the nectar to make honey (usually sold as Star Thistle Honey) and they can make more honey in less time if the flowers are all growing together in one place.
We saw many insects visiting the knapweed flowers to gather nectar and pollen, like this bumble bee.

In fact, like all flowering plants, spotted knapweed can be an important food source for a variety of insects. It has even been reported as a food plant for the endangered Karner Blue butterfly!
That is not to say that spotted knapweed is not causing ecological damage in areas where it has become invasive. In these areas it is endangering many native plant species that are also important food plants for insects and other animals. It's a very controversial plant and it is likely to stay that way for some time.