Photos of the Week – May 14, 2021

Next Thursday is World Bee Day. Prepare yourself for a deluge of social media and other information reminding you how dire the situation is for honey bees and why we need to save honey bees to save the world. If you can, try to redirect people toward the native bee species that really matter. If you’ve followed this blog for any length of time, you’ve heard why honey bees should not be the focus of our concern about pollinators. If you need a refresher, you can read this.

Native bees deserve a day of recognition. They deserve a lot more than that. However, it’s also worth remembering that bees are not the only group of pollinators that keep ecosystems humming along. Butterflies and moths are important. So are wasps, ants, and even beetles and hummingbirds. In some places, bats are hugely important too. But don’t forget about flies!

A fly (no idea what kind) feeds on a pussytoes (Antennaria) flower.
A bee fly feeds on stiff goldenrod (Solidago rigida).

Flies are the most diverse group of insects in North America, with an estimated 61,000 species. Many of those species feed on pollen and/or nectar as adults. Some are specialist feeders on certain plants and others are generalists. Some flowers rely on flies for pollination, but for most, flies just provide some additional help – a little insurance in case native bees or butterflies can’t fully do the job (maybe because honey bees are suppressing their populations).

A hover fly on spiderwort (Tradescantia).

One of the reasons flies aren’t always recognized as important pollinators is that many of them are mistaken for bees. That’s understandable – many of them look a lot like bees, with similar body shapes, coloration patterns, and behaviors. One fairly dependable way to tell them apart is to look at the antennae. Most bees have fairly long antennae, but flies tend to have short little stubby antennae right between their eyes. Speaking of those eyes, fly eyes are usually noticeably larger than bee eyes too. If you’re really close, or are looking at a dead insect, you can count wings – bees have four, flies have two.

Flies tend to have huge eyes and short, stubby antennae, which helps distinguish them from bees.

Another reason to celebrate the value of flies is that they tend to play two roles during their lives – one as larvae and a different one as adults. Bee larvae spend their childhood in the nest their mom built for them (in most cases) and feeding on the pollen and nectar their mom brought to that nest. That’s nice, but they’re not really doing much for the world at that point, are they?

Fly larvae, depending upon the species, might be eating manure or rotting meat, eating roots or other parts of plants, or hunting down other invertebrates or their eggs for food. In some cases, their mom lays an egg on a live caterpillar or other insect so the larvae, upon hatching, can burrow into that creature and eat it from the inside out. These are all important roles in ecosystems that help regulate ecological communities. Oh, and by the way, fly larvae are hugely important food sources for many other animals.

PLUS, they help out as pollinators when they grow up. That’s their side hustle.

I don’t know what kind of fly this is, but it’s feeding on a curly cup gumweed (Grindelia squarrosa) flower.
Tachinid flies are parasitoids and lay their eggs on other living creatures so the larvae can burrow into and eat them alive. It’s creepy, but a very important regulator of populations, including of many ‘pest’ insects.

So, on World Bee Day, and any day, really, let’s not forget about flies. Celebrate their diversity, the myriad roles they play, and even the horrific eating-creatures-alive-from-the-inside practices of a few of them. We’d sure miss them if they were gone.

Hover flies are small enough to be barely noticed, but are really abundant once you know what to look for.
This entry was posted in Uncategorized by Chris Helzer. Bookmark the permalink.

About Chris Helzer

Chris Helzer is the Director of Science for The Nature Conservancy in Nebraska. His main role is to evaluate and capture lessons from the Conservancy’s land management and restoration work and then share those lessons with other landowners – both private and public. In addition, Chris works to raise awareness about the importance of prairies and their conservation through his writing, photography, and presentations to various groups. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press. He lives in Aurora, Nebraska with his wife Kim and their children.

11 thoughts on “Photos of the Week – May 14, 2021

  1. Obviously no structural or coincidental accident that many flies appear as bees – Batesian mimicry. Also, bee larvae are actually contributing in an indirect way by causing their attending workers to make additional foraging trips to feed them, and in turn increasing the number of potential pollinations.

  2. Pingback: Photos of the Week – May 14, 2021 — The Prairie Ecologist

  3. What would make a difference is more land free from chemical fertilizers, pesticides and herbicides etc. And that’s why organic farming is the only sustainable way forward.

    • I understand your point. Farming with genetically modified crops has caused a crash in pollinator populations. In contrast, experts say that if the synthetic production of fixed nitrogen was stopped two billion people would starve to death. Tilling soil reduces soil carbon and destroys its structure. I can understand why people would choose to use synthetic chemicals. I can’t make enough compost to even amend my entire vegetable garden. Purchased manure has a lot to salt which can cause issues for plant growth if there is not enough rain to wash it away. As resources become more scarce, people will have to make more difficult decisions.

  4. Nice to have up close look at them — no flying away before I can have a good look. Thanks for posting and the info.

  5. Chris: I very much enjoy your work and wanted to share an excellent way to identify items in google images just click on images in the upper right hand corner and load in the image…Presto [image: Screen Shot 2021-05-17 at 8.14.20 AM.png] 402-210-1640

    On Fri, May 14, 2021 at 12:23 PM The Prairie Ecologist wrote:

    > Chris Helzer posted: ” Next Thursday is World Bee Day. Prepare yourself > for a deluge of social media and other information reminding you how dire > the situation is for honey bees and why we need to save honey bees to save > the world. If you can, try to redirect people toward t” >

    • I love an app “Seek” that was created by Cornell actually for children but serves as initial ID so input into iNaturalist is easier.

  6. What great photos of these tiny creatures. I appreciate the identification of them too. I often see small flies and bees in the garden and wonder what they are. Taking a photo of them is difficult.


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