Miscellaneous Sightings

One of the best perks of my job is simply that I get to be outside enough to see a lot of interesting ecological phenomena.  Today, I thought I’d share a few vignettes from the last couple weeks.

Monarch caterpillar (finally) on common milkweed.

Last year, we set out to count monarch caterpillars on our sites, hoping to compare numbers between various management treatments.  We were stymied by the fact that there were almost no caterpillars to be found anywhere, let alone enough to make comparisons.  This year, I assumed the numbers would be better, but since finding eggs and caterpillars in May from the early migrants from Mexico that arrived this spring, I haven’t seen any caterpillars until this week.  And I only found one this week.  Whoopee.

Dodder flowers on Maximilian sunflower. Platte River Prairies.

Dodder is a fascinating parasitic plant that wraps its plastic twine-looking self around prairie plants like sunflowers and goldenrods and more.  Later in the season, the orange twine dries up and disappears, leaving only the fuzzy spirals of flower/seed heads on the stems of its host plants.  If you didn’t see both of them together, you might never guess the twine and fuzzy spirals were from the same plant.  This week, dodder is in transition, with both flowers and twine at the same time.

A male brown-belted bumblebee (Bombus griseocollis) perches high in the prairie, hoping to find and mate with an emerging queen of its species.

A few years ago, I found out about a fun behavior by male brown-belted bumblebees.  As colonies start producing queens for the next year, males spread out across the prairie and wait for those queens to enter the world.  The males sit on tall perches for hours, scanning for big females.  Once they see one, they (and all the other males who spot her) race to be the first to mate with her.  This week, they were at it again.  I’m really glad to have been clued into this really cool phenomenon.  Otherwise, I’d probably just see the bees and assume they were resting.

Finally, I’d like to thank those who helped with and attended our field day last Saturday.  The forecast didn’t look promising but the rain cleared out right before the event started and we ended up having fantastic weather.  The attendance was lower than hoped because of the forecast, but we still had people from at least 7 states and U.S. territories and we all learned a lot about prairie ecology and invertebrates.  Big thanks to presenters Julie Peterson of University of Nebraska Extension, Rae Powers of Xerces Society, and Sarah Bailey of Prairie Plains Resource Institute, along with Kayla Mollet and Katie Lamke from the University of Nebraska-Lincoln.

Hey Ed, your mom caught a toad.

Julie Peterson (pink shirt, blue hat) shows attendees an insect.

Popular Sunflowers

Plains sunflower (Helianthus petiolaris) is an annual plant that responds quickly to bare ground in the Nebraska Sandhills.  They pop up after fire, intensive grazing, pocket gopher activity or something else allows light to hit the soil.  At times, they can be widespread, as they were the year after the 2012 drought. More often, they are found scattered about the prairie in patches of sparse vegetation.  They have started to bloom in earnest over the last couple of weeks, adding beautiful accents to the summer prairie.

Last week, I spent an hour photographing sunflowers and the wide variety of small creatures I found hanging about on them.  In just one hour, I spotted a pretty incredible abundance and diversity of invertebrates within an area smaller than my backyard.  Sunflowers, especially annual sunflowers, are considered by some to be weeds, but these native wildflowers play really important roles in prairie ecology.  Their seeds are extremely valuable as food sources for many wildlife species and their young leaves and flower buds/blossoms are quality forage for other species, including cattle.  During this time of year, the abundant and accessible pollen and nectar of the flowers is what seemed to be attracting the invertebrates I saw.  Here is a selection of photos displaying some of those sunflower visitors.

A variety of grasshopper, katydid, and tree cricket species are all commonly found feeding on the flower parts and pollen of sunflowers.  Weevils, long-horned beetles, and other beetles are also frequently seen.

Weevils and other beetles (including the one at the top right of this photo) were also present on many of the sunflowers I saw.

Hover fly

As a small female bee (Perdita albipennis) was gathering pollen from this sunflower, a male zipped in and began mating with her. She dragged him around and just kept foraging…

Wasps, like this paper wasp, were crawling around the stems and leaves of the sunflowers, apparently gathering extra-floral nectar that was also attracting abundant ants.

The abundance of herbivores, pollinators, and other insects on the flowers and vegetation of the sunflowers seemed to attract a number of predators as well, including robber flies, spiders, and assassin bugs.

A robber fly perches on a flower bud.

A tiny crab spider.

Assassin bug.

It was hard to see for sure, but I’m pretty sure this assassin bug was feeding on an individual of the same Perdita bee species shown above.

I hope these photos, all taken from a small area and within a short time period, help illustrate the kind of resource annual sunflowers can be in the Sandhills.  I’m sure many other wildflowers host similar numbers of invertebrates, but the height and conspicuous nature of sunflowers make it really easy to see and appreciate their value.

Annual sunflowers aren’t aggressive – they just take advantage of open soil and available root space.  As vegetation recovers from whatever event caused it to become sparse, sunflower abundance diminishes…until they get another opportunity to pop back from seeds and make their contribution to the prairie ecosystem.