Those Other Flower Visitors

If you look closely at wildflowers, you’ll often see insects moving around and between them. Many of those insects, of course, are bees, flies, butterflies, moths or other pollinators. While these small creatures are eating resources created by the plants they visit, they also provide services in return. The insects get pollen and/or nectar to feed themselves or their babies but also (unintentionally) facilitate the fertilization of ovaries that allow plants to produce seeds. It’s a pretty good trade all around – though with lots of variation in terms of how much each side benefits from the other.

All of that makes a pretty good story of cooperation among the earth’s creatures, but the full picture is much more complex. A strong percentage of insects hanging around flowers provide no benefits to the plants, and many do considerable damage instead. For today, I’ll ignore the predators who use flowers as hunting grounds, even though they are infinitely fascinating. Instead, I want to feature a few examples of ‘freeloading’ insects who take and take from flowers, but never give anything back. …Or at least don’t give back to the flowers.

Leaf beetles feeding on aromatic aster (Aster oblongifolius). Nikon 105mm macro lens. ISO 500, f/14, 1/320 sec.
A longhorn beetle on upright yellow coneflower (Ratibida columnifera) with its face full of pollen after eating. Nikon 105mm macro lens. ISO 125, f/20, 1/80 sec.

Numerous beetle species feed on flowers, eating pollen and nectar, but also petals, anthers, and other vital anatomical features. Some of these beetles can provide pollination services if they move between blossoms, but that benefit can often be outweighed by the destruction they create. Depending upon the number of beetles working over a flower, that level of destruction can be minor or catastrophic for a particular plant.

That doesn’t make these beetles evil or deserving of our dislike, however. Beetles have a right to make a living too, and there are plenty of flowers for everyone in a prairie (or even a garden) that’s well-managed. In fact, as I argued in a recent post, providing flowers to feed beetles and many other creatures should be part of our role as gardeners and land managers. Beetles play all kinds of vital roles in ecosystems, so keeping them around is certainly a good thing (excepting invasive species like Japanese beetles, of course, which can create far more devastation then benefits.)

Oil beetle on pasque flower (Pulsatilla patens) at the Niobrara Valley Preserve. Nikon 105mm macro lens. ISO 400, f/20, 1/640 sec.
Weevils on Platte thistle (Cirsium plattensis) at the Niobrara Valley Preserve. Nikon 105mm macro lens. ISO 320, f/14, 1/125 sec.
Grasshopper on plains sunflower (Helianthus petiolaris) at the Niobrara Valley Preserve. Nikon 105mm macro lens. ISO 400, f/14, 1/160 sec.

Grasshoppers, katydids, and crickets represent another group of insects that are often found chomping on flowers. These little scamps feed on multiple parts of the flowers, but they probably provide even less accidental pollination than beetles do. However, like beetles, this group of long-legged buggers is really good to have around. If nothing else, they are a major food source for birds and many other small predators (and there’s much more to them than just that but that’s another post). Instead of getting mad at grasshoppers for eating flowers, we should be expressing gratitude to plants for creating enough flowers to support grasshopper populations!

Tree cricket on tall thistle (Cirsium altissimum). Platte River Prairies. Nikon 105mm macro lens. ISO 640, f/18, 1/80 sec.

Caterpillars and similar-looking larvae of flies, beetles, and other insects are also commonly-found feeding on flowers. As with beetles and grasshoppers, the result can be pretty negative for individual flowers, but – again – the sacrifices made by those plants help support the broader ecosystem. Caterpillars are another huge food source for other animals and the vast majority end up as food rather than moths, butterflies, or other adult insects. They might as well enjoy a good meal while they can, right? I’ll also admit my personal bias here, since my favorite insect in the world is a little flower-eating caterpillar.

Annual sunflower (Helianthus annuus) being eaten by caterpillars of several larval stages. Nikon 105mm macro lens. ISO 640, f/13, 1/640 sec.
Giant robber fly (Promachus vertebratus) laying eggs on stiff sunflower (Helianthus pauciflorus). Nikon 105mm macro lens. ISO 500, f/10, 1/250 sec.

Sometimes, the way insects utilize flowers is less obvious than a big ol’ caterpillar chewing on the anthers and pollen of a sunflower. Loads of insects use flowers as a place to lay eggs, many of which hatch out and then feed on the flower – often hidden from our view. Others, like the giant robber fly pictured above, apparently lay eggs in flowers only so their larvae can drop off and burrow into the soil to chase down beetle larvae (thanks beetles!). So why do they lay their eggs in flowers and not in the soil? I have no idea.

More commonly, insects laying their eggs in flowers because that flower will provide both their home and their food source once they hatch. Some of those larvae eat parts of the flower itself, but many feed on the developing seeds, taking advantage of those highly concentrated packets of nutrition. If you peel open the head of a thistle or sunflower after it has stopped actively blooming, you’ll often find a few tiny ‘grubs’ chewing on the seeds within.

Once again, you could denigrate those larvae and their parents as pests if you like, but you’d be missing the larger picture. Those blossom-chompers and seed-munchers are part of the incredibly complex and interconnected web of prairie life. The give-and-take relationships between flowers and insects have existed for millennia and will continue for many more. This spring and summer, as you wander prairies, gardens, and other places where flowers bloom, consider paying a little extra attention to who else is enjoying those same blossoms. Those other visitors will undoubtedly have stories worth learning.

Fruit fly on tall thistle (Cirsium altissimum), probably scouting for a good place to lay her eggs. Nikon 105mm macro lens. ISO 640, f/16, 1/400 sec.
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.

6 thoughts on “Those Other Flower Visitors

  1. Chris, so grateful for these comprehensible little nuggets of nature ed. Expands my knowledge AND my “depth of field.” Thank you. Spring is springin’!

  2. Always love the detailed close up photos you take. We usually overlook the details of the bugs lest we have some crawl onto our noses! Amazing the variety of bugs and what they do!!!
    Thanks

  3. Chris, Thanks for the post. I do nature hikes at Soapstone Prairie Natural Area north of Fort Collins, so will enjoy sharing some of your insights in the future. Regards, Gary

    R. Gary Raham Author/Illustrator http://www.rgaryraham.com

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