Without These Flies, There'd Be No Chocolate

It's time to show some gratitude for the scavengers and pollinators that keep our planet healthy.

By Liz Langley
Published 22 Nov 2017, 15:18 GMT
A gall midge pollinates cacao, the plant that provides the main ingredient for chocolate. The most ...
A gall midge pollinates cacao, the plant that provides the main ingredient for chocolate. The most famous cacao pollinator is the chocolate midge.
Photograph by Mark Moffett, National Geographic Creative

As Christmas approaches, many people are slowing down to consider what we’re thankful for.

We'd like to nominate dung beetles.

These avid recyclers are just one of many species that fly under the gratitude radar, yet keep our world clean and delicious. Here are some others to add to your list.


Bees may be famous for pollinating, but when it comes to carrots, “flies are actually much more important pollinators,” says Ed Spevak, curator of invertebrates at the Saint Louis Zoo in Missouri.

The large, flat blossoms of the carrot flower are attractive to blue bottles, blowflies, and hover flies—so thank them for the carrot cake, he says.

To those of you who can't live without your chocolate, it's time to show your appreciation for another tiny fly, Spevak says. (Watch the ancient art of chocolate-making.)

Chocolate midge flies pollinate cacao trees of Central America, South America, Africa, and Asia. The insects are about one to three millimetres long, allowing them to fit inside the plant's small flowers.

If we ever see such a midge, we’ll apologise for swatting house flies and respectfully ask them to get back to work.


Dung beetles keep our world tidy by breaking down animal faeces, which it uses as both food and housing. (Read "Weird and Fascinating Ways Animals Use Poop.")

Case in point: when settlers brought sheep and cattle to Australia, there were no native dung beetles that could process their dung, says Max Barclay, senior curator at the Natural History Museum in London.

All that sun-baked dung made growing grass for the cows difficult, and disease incidence increased. Introducing an African dung beetle that specialises in cow dung took care of the problem.

Critically endangered American burying beetles entomb dead animals “in an underground crypt” so their offspring can feed on the carcass, Barclay says.

“It’s as close as any insects come to really parental care of the kind we see in larger animals.”


Vultures have the massive task of scavenging and recycling carcasses—a crucial ecosystem role made all the more obvious by their absence, Spevak says.

A white-rumped vulture is seen at Kamla Nehru Zoological Garden in India.
Photograph by Joël Sartore, National Geographic Photo Ark

Vultures are declining worldwide due to poisoned carcasses, habitat loss, hunting, and more.

Africa has already lost one of its eleven vulture species—the cinereous vulture—and now seven others are listed as either critically endangered or endangered.

In Asia, species such as the white backed vulture, slender-billed vulture, and long-billed vulture declined by 96 percent due to poisoning from an anti-inflammatory drug in cattle carcasses.

Feral dogs replaced vultures as scavengers, a shift thought to have partly caused a human rabies outbreak. (Related: "India Vulture Die-Off Spurs Carcass Crisis.")


There's no doubt climate change is harming salamanders, but some American woodland species are fighting back.

The common ensatina, also known as the redwood salamander, could help California combat climate change.
Photograph by Joël Sartore, National Geographic Photo Ark

A 2014 study found that some of the amphibians could actually combat climate change by sequestering carbon.

Insects release the greenhouse gas when they exhale and eat leaf litter on the forest floor. But if salamanders eat those insects, more carbon stays below the leaf litter and out of the atmosphere. (Read how the hidden costs of climate change could cost billions a year.)

“The impact of these small salamanders could be tremendously important to ecosystems like redwood forests,” says David Blackburn, curator of amphibians and reptiles at the Florida Museum of Natural History.


A young eastern grey squirrel shows curiosity at Saint Francis Wildlife, a rehab center in Florida.
Photograph by Joël Sartore, National Geographic Photo Ark

“We wouldn’t have forests like we do without rodents like rats and squirrels,” Rebecca Bearman, assistant curator of Birds and Program Animals at the Zoo Atlanta, says by email.

That's because rodents cache seeds in places with few predators—namely, areas with less trees. Forgotten or abandoned seeds grow into trees, which thrive in such low-competition environments.

Eastern grey squirrels of North America, for example, are fond of "planting" red oak trees.

Way to grow, little guys!

Have a question about the weird and wild world? Tweet me or find me on Facebook. Weird Animal Question of the Week answers your questions every Saturday—except for this week's special Thanksgiving edition.


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