Beetles And Pollination – Information About Beetles That Pollinate


By: Teo Spengler

When you think of insect pollinators, bees probably come to mind. Their ability to hover gracefully in front of a blossom makes them excellent at pollination. Do other insects pollinate too? For instance, do beetles pollinate? Yes, they do. In fact, nature relied on beetles that pollinate to propagate flowering species before hovering bees arrived on the planet. The story of beetles and pollination is a fascinating one that you can read right here.

Are Beetles Pollinators?

When you first hear about beetles and pollination, you are likely to ask questions: Do beetles pollinate? How are beetles pollinators? That’s because beetles share the pollinating role with other insects and animals today like bees, hummingbirds, and butterflies. Beetles were the first pollinators, starting hundreds of millions of years ago.

Pollinating beetles developed relationships with flowering plants a long time ago, before bees evolved as pollinators. While the role of beetles as pollinators is not as great today as in yesteryear, they are still important pollinators where bees are scarce. You may be surprised to learn that pollinating beetles are responsible for the majority of the world’s 240,000 flowering plants.

Given the fact that 40 percent of all insects on earth are beetles, it is no surprise that they do a significant slice of Mother Nature’s pollination work. They started some 150 million years ago pollinating angiosperms like cycads, 50 million years before bees appeared. There’s even a name for the process of beetle pollination. It’s called cantharohily.

Beetles cannot pollinate all flowers, of course. They do not have the ability to hover like bees, nor do they have long beaks like hummingbirds. That means that they are limited to pollinating flowers with shapes that work for them. That is, pollinating beetles cannot get to the pollen in trumpet-shaped flowers or where pollen is deeply hidden.

Beetles that Pollinate

Beetles are considered “dirty” pollinators, as opposed to bees or hummingbirds, for example, because they eat flower petals and also defecate on flowers. That has earned them the nickname of “mess and soil” pollinators. Yet, beetles remain an important pollinator worldwide.

Beetle pollination is quite common in tropical and arid regions, but quite a few common temperate ornamental plants also rely on pollinating beetles.

Often, the flowers visited by beetles have bowl-shaped flowers that open during the day so their sexual organs are exposed. The shape creates landing pads for the beetles. For example, magnolia flowers have been pollinated by beetles since the plants appeared on the planet, long before the bees appeared.

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In Defense of Plants

Magnolias are one of those trees that even the non-botanically minded among us will easily recognize. They are one of the more popular plant groups grown as ornamentals and their symbolism throughout human history is quite interesting. But, for all this attention, few may realize how special magnolias really are. Did you know they they are one of the most ancient flowering plant lineages in existence?

Magnolias first came on to the scene somewhere around 95 million years ago. Although they are not representative of what the earliest flowering plants may have looked like, they do offer us some interesting insights into the evolution of flowers. To start with, the flower bud is enclosed in bracts (modified leaves) instead of more differentiated sepals. The "petals" themselves are not actually petals but tepals, which are also undifferentiated. The most striking aspect of magnolia flower morphology is in the actual reproductive structures themselves.

Magnolias evolved before there were bees. Because of this, the basic structure that makes them unique was in place long before bees could work as a selective pressure in pollination. Beetles are the real pollinators of magnolia flowers. The flowers have a hardened carpel to avoid damage by their gnawing mandibles as the feed. The beetles are after the protein-rich pollen. Because the beetles are interesting in pollen and pollen alone, the flowers mature in a way that ensures cross pollination. The male parts mature first and offer said pollen. The female parts of the flower are second to mature. They produce no reward for the beetles but are instead believed to mimic the male parts, ensuring that the beetles will spend some time exploring and thus effectively pollinating the flowers.

It is pretty neat to think that you don't necessarily have to track down a dawn redwood or a gingko to see a plant that has survived major extinction events. You can find magnolias very close to home with a keen eye. Looking at one, knowing that this is a piece of biology that has worked for millennia, is quite astounding in my opinion.


Beetles: Nature's mess and soil pollinators

Soldier beetle (Photo © Stephen Luk)

Pollinators are extremely important. Not only are they responsible for one out of every three bites of food we eat, but they are vital in creating and maintaining the habitats and ecosystems on which many animals rely for food and shelter.

Beetles are one such pollinator. Of the world’s almost 350,000 flowering plants, it is thought that beetles are responsible for pollinating close to 90 percent of them. However, most beetles that visit flowers are not there for the nectar. Instead, they often chew their way through flowers and some species tend to leave their droppings behind, earning them the name “mess and soil” pollinators.

Very few plants are primarily pollinated by beetles. Those that are dependent on beetles are called cantharophilous plants. They are often fragrant and give off a spicy scent that attracts beetle pollinators. Beetles typically visit bowl-shaped flowers that are white or green, such as magnolias, smell strongly of fruit and have lots of pollen.

It is thought that beetles were among the first insects to visit flowers. In fact, fossil records show that beetles started visiting flowers 200 million years ago (during the Mesozoic period), roughly 50 million years before bees. Today’s beetles seem to prefer pollinating the close descendents of ancient flowers, such as magnolias, water lilies and spicebush.

Tumbling flower beetle (Photo by Tom Murray)

Beetles thought to pollinate flowering plants include (but are not limited to):

  • Members of the tumbling flower beetle family, of which 56 species are native to Canada. Tumbling flower beetles are commonly found on umbelliferous plants — plants on which the flowers arise from the same point on the main stem and culminate in a cluster with the youngest flowers at the centre, forming a flat-topped head.
  • Members of the soldier beetle family, several species of which are native to Ontario. These beetles are related to the lightning bug family (fireflies) but produce no light. They are easily attracted by single-flowered marigolds and members of the daisy family. Goldenrods are soldier beetle magnets, as are many native shrubs and trees.
  • Members of the checkered beetle family, native species of which are found across Canada. Adults of this species feed on pollen from plants like sunflowers.

Checkered beetle (Photo by Lynette)

Have you voted for your favourite native pollinator yet? If not, click here to cast your vote and sign up to receive access to a free Father’s Day e-card featuring the winning pollinator!

About the Author

Amy Anastasopoulos is NCC's manager of direct response marketing.


Friends Not Foes

Ladybugs, Japanese beetles, rove beetles, ground beetles, fireflies, click beetles, soldier beetles, dung beetles—whether this is a list of your farm friends or foes, recognize the beetle for what it is: a low-lying, ground-burrowing, adaptable, diverse order of animals, outfitted with built-in armour and wings. It has survived in one form or another for at least 270 million years. If I were a flowering plant hoping for a future partner in life, I’d start making myself really interesting to beetles, maybe try to tone down my floral perfume to something more skunky, just as a little insurance policy in the game of life.


Beetles

There are more different kinds of beetles on the planet than any other group of creatures. Beetles have been around for a very long time, hundreds of millions of years, in fact. Some beetles developed relationships with plants as specialised pollinators even before bees had appeared on the scene! Beetles are important pollinators in some habitats where bees are scarce, including some very arid areas.

Flowers that are pollinated by beetles tend to be larger and produce a musty or fruity scent to attract the beetles. A number of palm tree species, including the Oil Palm, are pollinated by specialised beetles.

In East Africa one ancient group of plants, the cycads, are pollinated by beetles, including weevils, that complete their lifecycle within the reproductive cones produced by the plants. As there are separate male and female cycads, the pollinators are essential for the survival of some of these magnificent, rare plants in the wild.

Beetles of many different kinds including chafers, longhorns and leaf beetles, visit flowers in large numbers. However, they mostly feed on the flowers, causing some damage, and don’t serve as efficient pollinators


Conclusion

They’re important to us in so many ways, the question is are we looking after them enough, are we creating the right habitats for them to thrive in. Are we responsibly introducing the right varieties into the right places to make it sustainable?

Ladybugs are far from going extinct and certainly are not near the danger levels that Bees face. But we don’t want them to get to that point for many reasons.

I say, let’s keep putting in the plants and habitat that attracts them and nature will do the rest for us. We love mother nature, she is amazing.

For Ladybug lovers like me, I’ve curated over the years a special list of Ladybug Gifts, as well as FREE Education Resources for Classroom and homeschooling use. I hope they help.


Watch the video: Salvia pollination and lever mechanism


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