Nav: Home

Fossil fly with an extremely long proboscis sheds light on the insect pollination origin

April 01, 2019

A long-nosed fly from the Jurassic of Central Asia, reported by Russian paleontologists, provides new evidence that insects have started serving as pollinators long before the emergence of flowering plants. Equipped with a proboscis twice the length of the body, this fly predates the first angiosperms by about 40-45 million years. This suggests that insect pollination began to evolve in association with ancient gymnosperms.The results of the study are published in Gondwana Research.

Archocyrtus kovalevi is only known as a single compression fossil found in the Late Jurassic rocks in Southern Kazakhstan. The fossil, estimated to be about 160 million years in age, first came into light in 1996, but its original description did not contain any photos. It is no wonder that nobody believed at first that this fly had evolved a proboscis of such proportions so early in time. Despite not having seen the specimen itself, skeptics said that the long structure next to the fly's body was not a genuine proboscis, but must be a piece of plant or other stray object. As a result, a remarkable finding fell into oblivion for more than 20 years.

To dig up the truth about the enigmatic fossil, paleontologists from Borissiak Paleontological Institute (Moscow) reexamined it using modern microscopic techniques and element distribution analysis. This allowed them to confirm the presence of a long proboscis, which has an easily discernible food canal and is identical to mouthparts of living long-proboscid flies in all other respects. Measuring 12 mm long, mouthparts of A. kovalevi is 1.8 times longer than the body. It means that this tiny fly ranks first among all the Mesozoic insects in having the longest proboscis relative to body size.

A. kovalevi is the earliest fossil record of extant family Acroceridae, or small-headed flies. Nowadays, there are a few species of small-headed flies with a proboscis longer than body found in the Americas and South Africa. The present-day members of Acroceridae use their oversized proboscis to draw nectar from long tubular flowers, acting as pollinators in the process. The unusual thing is that A. kovalevi existed at the time when not a single flower was blooming. The first flowering plants emerged much later, in the Early Cretaceous, and at first had small, inconspicuous flowers. So what was the proboscis of A. kovalevi used for?

"There is a well-known story about Charles Darwin, who famously predicted the existence of a pollinating moth with a long proboscis after seeing the deep nectar spur of the Madagascar orchid. We have to argue the other way round and conclude from the ancient long-nosed fly that we see to a plant which it may have pollinated", said Alexander Khramov, the first author of the study and a senior researcher at Borissiak Paleontological Institute.

Luckily, researchers did not need to go too far in their guesses. Dozens of cones of the plant called Williamsoniella karataviensis have been collected from the same strata as the fly. This plant belongs to Bennettitales, an extinct group of the Mesozoic gymnosperms, many of which had showy, flower-like reproductive organs, and on this ground scientists have long suspected them to be insect pollinated. W. karataviensis fits into this picture perfectly. It has bisexual cones consisting of twelve petal-like bracts (modified leaves) arched over the ovules (precursors of seeds). Like modern Gnetales, a relict group of gymnosperms pollinated by insects, including flies, ovules of W. karataviensis could have produced sugary pollination drops.

The depth of the cones of W. karataviensis roughly matches the length of proboscis of A. kovalevi, so the pieces of the puzzle come together: small-headed flies first evolved an extremely long proboscis to get an access to the sugary secretions hidden deep in the cones of ancient gymnosperms. It is highly probable that they did pollination work in return for sweet reward. It follows that the foundation of pollination mutualism between plants and insects had been laid long before the first true flowers adorned the Earth. When the Mesozoic gymnosperms left the stage, Acroceridae and probably some other long-proboscid insects offered their pollinating services to newly emerged flowering plants.

AKSON Russian Science Communication Association

Related Fossil Articles:

Fossil fish gives new insights into the evolution
An international research team led by Giuseppe Marramà from the Institute of Paleontology of the University of Vienna discovered a new and well-preserved fossil stingray with an exceptional anatomy, which greatly differs from living species.
What color were fossil animals?
Dr. Michael Pittman of the Vertebrate Palaeontology Laboratory, Department of Earth Sciences, The University of Hong Kong led an international study with his PhD student Mr.
New Cretaceous fossil sheds light on avian reproduction
A team of scientists led by Alida Bailleul and Jingmai O'Connor from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences reported the first fossil bird ever found with an egg preserved inside its body.
Fossil deposit is much richer than expected
Near the Dutch town of Winterswijk is an Eldorado for fossil lovers.
Researchers add surprising finds to the fossil record
A newly discovered fossil suggests that large, flowering trees grew in North America by the Turonian age, showing that these large trees were part of the forest canopies there nearly 15 million years earlier than previously thought.
Chinese Cretaceous fossil highlights avian evolution
A newly identified extinct bird species from a 127-million-year-old fossil deposit in northeastern China provides new information about avian development during the early evolution of flight.
Parasites discovered in fossil fly pupae
Parasitic wasps existed as early as several million years ago.
Cracking open the formation of fossil concretions
Researchers developed a unified model of the formation mechanism of spherical carbonate concretions, which often contain exceptionally well-preserved fossils.
First an alga, then a squid, enigmatic fossil is actually a fish
A fossil slab discovered in Kansas 70 years ago and twice misidentified -- first as a green alga and then as a cephalopod -- has been reinterpreted as the preserved remains of a large cartilaginous fish, the group that includes sharks and rays.
Actual fossil fuel emissions checked with new technique
Researchers have measured CO2 emissions from fossil fuel use in California and compared them to reported emissions.
More Fossil News and Fossil Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at