Parasites have turned out to be “invisible influencers” of all ecosystems


Tribute to bloodsuckers

A crash course in the overlooked world of parasites

parasites: The inside story
by Scott L. Gardner Judy Diamond and Gabor Rácz
Illustrated by Brenda Lee
Princeton University Press, 2022 ($29.95)

Raised on a farm in Oregon’s Willamette Valley, Scott L. Gardner scoured the rolling hills for the carcasses of mice, pheasants, and other deceased wildlife. However, it wasn’t those larger animals that intrigued the young naturalist, but the smaller life forms nestled in their organs and flesh. Gardner was looking for their parasites.

Gardner’s uncle, Robert L. Rausch, was a leading parasitologist with a career spanning more than 60 years. Gardner regularly mailed coiled worms, teardrop-shaped flukes, and other specimens he found in his dissections to his uncle for help in identification. One of them, a tapeworm Gardner fished from a camas pocket gopher, turned out to be a species new to science. Later he called him Hymenolepis tualatinensisafter the Tualatin River where he had discovered it.

Gardner was fascinated, so to speak. He went on to become a parasitologist at the University of Nebraska-Lincoln, where he is also curator of the Harold W. Manter Laboratory of Parasitology, one of the largest parasitology collections in the world. In Parasites: The Inside Storywhich Gardner co-authored with his colleagues Judy Diamond and Gabor Rácz, shares the story of H. tualatinensis to make a broader point about parasites: these species are all around us but unfortunately little studied. However, more and more scientists are learning that parasites are facing the same survival pressures as free-living animals, including climate change, habitat loss and other anthropogenic stressors. In fact, around his family’s farm today, the tapeworm he discovered just a few decades ago is “nowhere to be found.”

Disappearances of parasitic species such as H. tualatinensis they are much more likely to go unnoticed than the decline of songbirds or butterflies. Parasites are grossly overlooked by scientists and the public alike, and when they are recognized, they are usually singled out only as agents of disease and death. However, as the authors point out, our understanding of nature is glaringly incomplete without an understanding of parasites. These “invisible influencers” affect virtually every other species on the planet and create complex communities within each environment, communities that ultimately drive the ecology of those systems. Parasites, they say, form “the scaffolding for all interactions between organisms.”

Parasites provides a crash course in how ubiquitous these interactions are. The authors describe parasitoid wasps that lay their eggs inside the cocoons of other parasitoid wasps, for example, and leeches that spend their entire lives inside the anus of hippos. The parasites also appear to have found their way into every inch of the planet, from the dry valleys of Antarctica to the highest levels of the atmosphere, where they are sometimes blown away. Ecologists increasingly agree that parasites play as important a role in shaping ecosystems as predators do.

The parasites can take up to five hosts to go from egg to larva to adult and one of the most delicious parts of Parasites includes 11 figures – mini comics, really – by illustrator Brenda Lee. Each describes the life cycle of a different parasite, from the human roundworm’s beginnings as an egg in a pile of curled feces to the prolific expulsion of the tapeworm’s terminal segments from a sperm whale’s rectum which explode into millions of eggs. Outside of the whale these eggs are eaten by zooplankton, where they hatch into larvae. The infected zooplankton are in turn eaten by the fish that are eaten by the whales, starting the cycle all over again.

Despite this codependent lifestyle, parasites can be opportunistically agile, “switching hosts over time as opportunities for new colonization become available,” as Gardner and his colleagues write. Tapeworms, for example, survived the most recent asteroid impact that wiped out three-quarters of all life on Earth by switching from marine hosts to seabirds. However, codependency can also make parasites vulnerable. If the host of a parasitic species suddenly dies out, or if conditions change precipitously, the parasites may also disappear.

Parasites it works best when he delves into the details of these amazing life stories and the evolution behind them. As a primer on the subject, it was a snappy read. But I would have liked a more direct narration of the authors’ experiences. Anecdotes such as Gardner’s discovery of the tapeworm in childhood H. tualatinensis are shared in the third person meaning readers are left wondering how Gardner felt when he realized he had found a new species and what his reaction was when it occurred to him that the species had disappeared .

Gardner and his coauthors do not explain what caused the disappearance of H. tualatinensis. Most likely, as with so many other mysteries surrounding parasites, they just don’t know. They suggest it may have been the victim of “human mismanagement of the environment,” switching to a new host or disappearing from the region entirely. What the authors can say with certainty is that ‘the imminent loss of parasite diversity will forever reduce our understanding of how whole communities of organisms interact and evolve’. —Rachel Nuwer

Rachel Nuwer is a freelance journalist and author whose work has appeared in the New York Times And National Geographic.

Fair measures

Measurements can be used to advance or exploit

Credit: ATU Images/Corbis/Getty Images Plus

Oversized: The hidden history of measurement from cubits to quantum constants
by James Vincent
WW Norton, 2022 ($32.50)

Scientific breakthroughs are often associated with dramatic insights, such as when the proverbial apple fell on Newton’s head. But journalist James Vincent, who covers science and technology for The limitargues that true progress is built inch by inch.

In Beyond measure, Vincent tells the story of metrology by exploring how humanity and measurement have shaped each other throughout history. It’s an ambitious project that spans centuries, from the ancient Egyptians predicting feasts or famines from the annual depth of the River Nile to tracking and monetizing our online self-measurements by tech companies like Google and Facebook.

Vincent masterfully draws meaning from every millimeter. He explains how informal measurements like the pinch (like the amount of salt used in cooking) and the cubit (the length from the elbow to the fingertips) highlight an intimate relationship between metrology and our bodies. He next describes how the French Revolution was in part aided by the politics surrounding the metric system.

With such a wide range of topics, including the creation of the first thermometer, Albert A. Michelson’s experiments to determine the speed of light, and our modern reality where human behavior is reduced to a set of statistics such as BMI in health – Care industry: Vincent has a tendency to jump back and forth in time. This can sometimes make it difficult to follow, but it never sours the reader’s curiosity in the rich historical context he provides. The book is filled with wonder and love for a field that many of us have mistakenly associated with emotionless objectivity.

Beyond measure he especially shines when portraying the innate confusion of metrology. Vincent doesn’t just tell us that it’s hard to find consensus on how to measure distance; he shows how the field is inextricably linked to nation-building, as governments throughout history have used varying valuations to cheat farmers or to steal, divide and colonize the lands of indigenous peoples. It also addresses the more sinister uses of science, such as how statistics were leveraged to support eugenics in the late 1800s. In doing so, Vincent creates a clear and complex picture of measurement as both a tool of radical social advancement than submission, depending on who handles it. —Michael Welch

In short

In the name of plants: From Attenborough to Washington, the people behind the plant names
by Sandra Knapp
University of Chicago Press, 2022 ($25)

When Shakespeare asked, “What’s in a name?” he probably he didn’t expect such a literal answer as Sandra Knapp’s fascinating biographical compendium, In the name of plants. Some of these essays, spanning both world and history, center on hereditary figures, such as Darwin and Sequoia. Others are surprising (Lady Gaga has a fern named after her!) or strive to correct historical inaccuracies and erasures. But the book is not just an elegant reference text. It reminds us that the methods we use to classify things are inseparable from who we are. —Sarah Battie

The creative lives of animals
by Carol Gigliotti
NYU Press, 2022 ($30)

From cubs bowing playfully to alligators crooning seductively, Carol Gigliotti combines examples from interviews with scientists and excerpts from previously published books into this delightful index of animal inventiveness. Gigliotti explores the intelligence of animals by focusing on their creative approaches to problem solving, such as how prairie dogs modify their communication to describe something they’ve never seen before. Her decades spent teaching the arts to college students ignited her curiosity about the diversity of creativity, inspiring her to write a book that she argues “we don’t give meaning to the lives of animals; they are able and willing to do it themselves. —Fionna MD Samuels

Resurrected Africa: A new era of speculative fiction
edited by Sheree Renée Thomas, Oghenechovwe Donald Ekpeki and Zelda Knight
Tordot com, 2022 ($27.99)

In Africa resurrected, bewitching technologies and devastating magics explode from Africa and its diaspora in stories of once-human androids crumbling in their quest to live forever, mortals rushing to become gods, and climatic disasters. This vibrant anthology – a well-paced feast of today’s most thrilling speculative fiction – has 32 short stories written by black authors from around the world. With settings from deserts too dry to cry to virtual realities where anyone can rise or fall from power, Africa resurrected embrace darkness and struggle as readily as hope and fantasy. —Sasha Warren

November Recommended Books.

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