Do you know why the common name in English for Helianthus is sunflower? The common name is the same in Dutch (zonnebloem), German (Sonnenblume) and several other languages. In French (tournesol) and Spanish (girasol), the common names refer to “turning to the sun”, an accurate description of how this plant behaves.
Sunflowers exhibit a phenomenon known as heliotropism — an inclination to turn East in the morning so that the developing buds are warmed by the sun. The plant heads track the sun during the day and, at night, they reorient themselves to face East again. So if you pay attention when you visit a sunflower field at different times of day, you’ll notice they face a different direction in the morning and afternoon.
It’s not only birds, butterflies — and people! — that enjoy sunflowers. When these flowers grow in abundance, plenty of varied insects come to enjoy them and I’ll share something about these “sun worshippers” with you.
American bumble bees (Bombus pensylvanicus) were foraging on nearby hibiscus blooms.
At a different site in neighboring Durham county, where sunflowers bloom later, I saw bumble bees on partridge peas and other yellow flowers.
There, too, my attention was caught by a bee that looked quite different from others that I’d seen. It proved to be a leafcutter bee (Megachilid), which has large mouthparts that enables it to cut pieces of leaves, plant resins and soil to line its nest.
The leafcutter bees are interesting in their unique method of carrying pollen. Rather than collect pollen in baskets called corbicula on their hind legs, they gather the substance in a clump of abdominal hairs called a scopa or pollen brush.
Back at the sunflower fields, I observed one medium-sized cuckoo bee (Epeolini) eventually become covered with sunflower pollen. These bees do not have an anatomical structure for carrying collected pollen and the females, like avian cuckoos (or cowbirds), lay their eggs in other bees’ nests.
The much smaller Western honey bees (Apis mellifera) were very numerous. It was interesting to discover that for some time, the NASA website included a section on honey bees! It stopped being updated when the principal investigator retired but NASA maintains the site because of the valued information it contains. Some of the interesting facts they listed about these insects:
- Bees can fly about 20 mph (32 kph).
- The highest recorded number of eggs laid by a queen was 2,000 per day!
- Bees have been on our planet for about 30 million years!
- To make 1 pound (0.45 kg) of honey, bees need to collect nectar from about 2 million flowers!!
- The average foraging bee (all females) makes about 1/12th of a teaspoon of honey in her lifetime.
- The main way in which honey bees communicate among themselves is via chemicals called pheromones.
The honey bees and common Eastern bumble bees make a good choice by spending lots of time in sunflower fields. Scientific studies indicate that ingested sunflower pollen enables them to suffer less infection from two common parasites, a real boon for bees who might otherwise succumb to colony collapse as a result of disease.
Both in the sunflower and other fields, it was fascinating to see other types of small bees as well. The small green sweat bees perhaps prefer more colorful blooms as that is where I mostly saw them.
There were some other interesting insects besides butterflies and bees in the sunflower fields and surrounding vegetation. While looking at some bumble bees circling a large sunflower head, I had inadvertently photographed a pair of much tinier insects near the center of the flower. I actually only noticed them when I was looking at the photos at home or I would have tried to focus on them better in the field.
When I enlarged the photo, I was able to get a somewhat fuzzy look at them and BugGuide identified them for me as sunflower seed maggots (Neotephritis finalis). These tiny insects have prettily patterned wings, but I discovered there is not a lot of information available about them; some research in North Dakota in 2008 concluded they might be a pest but no other data were easily available. They are a species of fruit fly.
Another insect seen on the sunflowers that many people find distasteful were the green June beetles (Cotinis nitida). The larva can damage vegetable and other plant roots, while the adults will feed on ripening fruit, so many gardeners will try to get rid of them.
Sunflower fields are beautiful and spending time observing them as interesting wildlife habitats can really be enjoyable. These flowers also constitute a beneficial cash crop for farmers who can sell the seeds for sunflower oil, for human and avian consumption and the stalks for cattle feed.
And as if all those benefits don’t make sunflowers enough of a value-laden plant, scientific studies have also shown that they assist in phytoremediation, a process that helps remove and destroy polluting contaminants in soil, water, and air. Their deep taproots help aerate soil and make it richer for growing other subsequent crops as well.
Some sunflower fields may still be blooming through August and an online search can help you find them if you’d like to enjoy these wonderful flowers and their wildlife beneficiaries. If you have a garden, you might consider adding sunflowers to your vegetation mix if you don’t have them already. You can still plant some now in hopes of late autumn blooms.
This is a good time also to remember that the Ukraine became the world’s leading exporter of sunflower seeds until the currently ongoing invasion of the country brought this trade to a halt. Farmers who were still able to grow the country’s national flower are stuck with supplies and no income. Consider supporting organizations that are working to provide the Ukrainian people with humanitarian aid:
- Ukraine Relief and Recovery
- Want to Support the People in Ukraine?
- Top-rated Charities to Help the Ukraine Relief Effort