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    Every Creeping Thing: True Tales of Faintly Repulsive Wildlife: “Conniff is a splendid writer–fresh, clear, uncondescending, and with never a false step; one can’t resist quoting him.” (NY Times Book Review)

    The Species Seekers:  Heroes, Fools, and the Mad Pursuit of Life on Earth by Richard Conniff is “a swashbuckling romp” that “brilliantly evokes that just-before Darwin era” (BBC Focus) and “an enduring story bursting at the seams with intriguing, fantastical and disturbing anecdotes” (New Scientist). “This beautifully written book has the verve of an adventure story” (Wall St. Journal)

    Swimming with Piranhas at Feeding Time by Richard Conniff  is “Hilariously informative…This book will remind you why you always wanted to be a naturalist.” (Outside magazine) “Field naturalist Conniff’s animal adventures … are so amusing and full color that they burst right off the page …  a quick and intensely pleasurable read.” (Seed magazine) “Conniff’s poetic accounts of giraffes drifting past like sail boats, and his feeble attempts to educate Vervet monkeys on the wonders of tissue paper will leave your heart and sides aching.  An excellent read.” (BBC Focus magazine)

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Triassic Butterfly Park: Oldest Fossil Unhinges Flower-Pollinator Timeline

Posted by Richard Conniff on January 10, 2018

Modern Glossata

By Richard Conniff/Scientific American

For years, researchers studying core samples drilled from deep in the Earth have noticed odd flecks of material, possibly from insects—and generally treated them as a distraction from the real work: They focused instead on pollen and spores as a continuous record for understanding past ecosystems. But a surprising abundance of those flecks in a recent sample from northern Germany has now led a team of researchers to pay closer attention.

Writing in the journal Science Advances, Timo van Eldijk and his co-authors describe their find as the earliest fossil record of Lepidoptera, from about 201 million years ago, at the boundary between the Triassic and Jurassic periods. The new find fits the timeline for evolution of the Lepidoptera suggested by molecular evidence and helps correct a puzzling gap in the fossil record.

Triassic Wing Scale

The study looks at 70 specimens, found in a drill core from more than 300 meters below the surface, and identifies them as the wing scales that give butterflies and moths their spectacularly varied colors and patterns.  A light microscope, and later a scanning electron microscope, revealed the scales to be petal-like structures.  Some of them are beautifully preserved, with neatly ridged surfaces, herringbone webbing between the ridges, “micro-ribs,” and in some cases, perforations in the surface.

The perforations turned out to be a critical detail. They indicate, according to the co-authors, that a moth of that period had the hollow wing scales characteristic of Glossata, the taxonomic group that includes all modern moths and butterflies equipped with a sucking proboscis. The oldest previously known such fossil was from 129 million years ago–just as the flowering plants were making their spectacular emergence across the planet.  And the accepted theory was that the sucking proboscis only emerged at that point as a product of co-evolution between flowers and the insects that pollinate them.

That co-evolution, and the often exquisitely precise matchup between flower and pollinator, have been a subject of perennial fascination for naturalists.  In one of the most celebrated stories in all of botany, for instance, Charles Darwin was examining a shipment of orchids from Madagascar that included one flower with its nectar hidden at the bottom of a foot-long  tube.  “Good Heavens what insect can suck it?” Darwin wrote to a friend.  The next day he conjectured that there must be a moth with a proboscis roughly that long to do the job.  Just such a moth, with an 11-inch-long coiled proboscis, finally turned up 45 years later.

But the new study pushes fossil evidence for the origin of the sucking proboscis back 70 million years and that “challenges the underlying notion,” the authors write, that the emergence of flowering plants roughly 130 million years ago drove the evolution of the Lepidoptera proboscis. They argue instead that the transition among the insects “to exclusively feeding on liquids was most likely an evolutionary response to widespread heat and aridity” during the late Triassic.

While some moths, including species represented in the same drill core sample, continued to have chewing mouthparts, the authors write, others evolved sucking mouthparts for drinking water droplets or sap from damaged leaves.  Although the published paper does not make this point, van Eldijk, a graduate student in evolutionary biology at Utrecht University, suggests that the early emergence of the sucking proboscis may even have helped drive the emergence of flowering plants, rather than vice versa.

Other scientists greeted the new find with excitement, for beginning to fill what University of Connecticut lepidopterist David Wagner called “this huge gap in the fossil record.” But Wagner also described the study’s interpretation of this new evidence as “widely speculative and likely wrong.” He questioned the idea that the proboscis evolved in response to aridity: “There are 24 other orders of flying insects” from the same period, he said, “that did just fine without having a suctorial proboscis.”  They got water “the way other animals do, they drink it, lap it, use capillary action, whatever.”  The short, simple proboscis in early Lepidoptera also has little to do, he said, “with the coiled proboscis that later evolved to get nectar from deep within a flower. There are just millions and millions of years of evolution between the emergence in these primitive Glossata and the long, straw-like proboscis for feeding in flowers. Not all tongues are created equal.”

William Friedman, an evolutionary biologist and director of the Arnold Arboretum at Harvard University, agreed: “I don’t think this necessarily changes the story of the coevolution of lepidopterans and flowering plants,” he said. “There are lots of biological structures that hang around with one function, and at a later point that function gets changed, or all of a sudden that function has a new context. Even if Lepidoptera are significantly more ancient, which is wonderful, that doesn’t mean that they diversify, that they do a million-and-one things.  They could be like ancient mammals, hanging around, being small and not doing much till the asteroid hits”–or in the case of the Lepidopteran proboscis, until the emergence of flowers.

Drill core sections

It will take other samples from other drill cores to fill out the fossil record and enable researchers to begin making sense of the evolutionary story, said Maria Heikkilä, a lepidopterist at the Finnish Museum of Natural History.  The specimens in the new study, from less than a third of ounce of material taken from one drill core, at least “show that there is potential.”

Past researchers haven’t looked at the insect material from drill cores in a systematic way, says Bas van de Schootbrugge, a pollen specialist at Utrecht University and senior author of the new study, “because you really need to pick them out. You have to imagine 70 scales amid millions and millions of pollens and spores.  If you want to do this on a larger time scale, it’s going to be a lot of work. But we are hoping that other people are going to follow.”

END

Richard Conniff is an award-winning writer for magazines and a contributing opinion writer for the New York Times. His books include House of Lost Worlds (Yale University Press, 2016) and The Species Seekers (W. W. Norton, 2010).

 

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