Shrimp on treadmills? Some science only sounds silly | Science News for Students

Shrimp on treadmills? Some science only sounds silly

Experiments that may seem odd almost always have a valuable purpose
Feb 20, 2017 — 12:39 pm EST
shrimp treadmill

Critics made fun of spending for "shrimp on a treadmill" research, but it was a small part of an important study into a disease afflicting this 'farmed' species.

D. Scholnick

BOSTON, Mass. — What could be sillier than a big shrimp running on a treadmill? When comedians heard about a scientist who made shrimp do his, plenty of them made jokes. A number of politicians did too. Some even complained about all the money those scientists were wasting. A few critics had argued that the researchers had spent up to $3 million. But the real joke is on those critics.

The treadmill, much of it cobbled together from spare parts, cost less than $50. And there was a serious scientific purpose in making those shrimp run. Researchers described this and a few other supposedly ridiculous projects here, on February 18, at the annual meeting of the American Association for the Advancement of Science. All of these projects had important goals. They also gleaned valuable data. 

Litopineas vannamei is commonly known as the Pacific white shrimp. These tasty crustaceans grow up to 230 millimeters (9 inches) long. They swim along the Pacific coasts of Mexico, Central America and parts of South America. For many years, most of these shrimp in grocery stores and markets had been caught by fishermen. Now, most are raised in captivity. They come from the aquatic equivalent of farms.

Worldwide, people have eaten more than 2 million tons of these farmed shrimp each year for the past decade.

(Story continues after video)

This shrimp probably looks pretty funny running on a treadmill. But some important science can be learned from these aquatic workouts.
Pac Univ

David Scholnick is a marine biologist at Pacific University in Forest Grove, Ore. There, he studies these shrimp, among other creatures. About 10 years ago, he was studying some shrimp farms plagued by large amounts of bacteria. He suspected the germs were making it tough for the shrimp to get oxygen from the water. Like a person with a heavy cold, it would be difficult for them to breathe. Scholnick also suspected sick shrimp would get tired more quickly than healthy ones. Indeed, the shrimp he was observing had normally been quite active. Now, they often remained motionless in their tanks.

The only way to test whether the animals were truly tiring too quickly was to give them a workout. He or someone on his team could prod the shrimp and chase them around the tank. But Scholnick thought there must be a better way. And his solution: a treadmill.

A budget-conscious MacGyver

Of course, companies don’t make treadmills for shrimp. So Scholnick built his own. Because his team’s budget was tight, he used spare parts that had been laying around. For the moving belt on the treadmill, he cut a rectangular piece of rubber from a large inner tube. He looped that conveyor belt around a couple of wheel assemblies taken from a skateboard. Those were mounted onto a scrap of wood. He used a small motor taken from another piece of equipment to power the treadmill. The only money he spent was $47 for the plastic panels used to build the tank that would hold the treadmill.

“Yes, the video of the shrimp on the treadmill looks odd,” Scholnick admits. “It’s easy to make fun of.”

But that part of the research was only a small part of a much larger project, he adds. And the summer that he and his team built their treadmill, they had a research budget of about $35,000. Most of that money went to paying paying team members (who, over the course of the summer, ended up making only about $4 per hour, Scholnick recalls).

Understanding the biology of a male duck’s reproductive organs — in mating season and at other times — has been described as silly science. But researchers need to know what drives changes in these ducks in order to keep them healthy.

But critics who thought Scholnick’s work was “silly” made it sound like the researchers wasted huge sums of money just for the fun of it. They even exaggerated the amounts by adding up all of the money that Scholnick had received for all of his other research studies. Some critics even included money received by other researchers who had worked with Scholnick on unrelated projects. The largest total some had reported was around $3 million — which could certainly get people mad if they didn’t understand the real story.

In fact, the work had an important goal. It sought to probe why this species’ immune system hasn’t been fighting off infection as it should. If he and other researchers can figure that out, they just might be able to develop a treatment. That, in turn, could let farmers raise larger numbers of healthy shrimp.

From ducks to killer flies

Many people criticize government spending on projects that appear silly, says Patricia Brennan. She knows about this from personal experience. An evolutionary biologist at the University of Massachusetts in Amherst, plenty of people have made fun of her work. Among other things, she’s studied the dramatic changes over the course of the year in the size and shape of sex organs in male ducks. They enlarge greatly during mating season. Later, they shrink again. In particular, she’s investigated whether those changes were driven by hormones. She also probed whether the change in size of those organs is affected by having to compete for mates with other males.

Such studies are important to understanding the basic biology of an important species.

screwworm larvae
In the 1950s, screwworm flies (larva shown) were a cattle pest that cost farmers and ranchers in the United States about $200,000 each year. Thanks to studies of the fly's mating habits that cost only $250,000 or so. The findings ultimaely saved U.S. farmers billions of dollars.
By John Kucharski [Public domain], via Wikimedia Commons/U.S. Department of Agriculture

Yet critics seem to be especially fond of poking fun at biological studies, Brennan claims. She cited several other examples of such allegedly “silly” science. One was using robotic squirrels to study the behavior of rattlesnakes. The sight of a robotic squirrel is easy to make fun of. But that was just a small part of an investigation into how the heat-sensing pits on a rattlesnake’s snout are used to track its warm-blooded prey.

“People often wonder why scientists study the sex lives of odd animals,” says Brennan. That’s a good question, she notes. But, she adds, there also are usually very good answers. Take, for example, the screwworm fly. They are a big pest in the developing world. Some 65 years ago, they also were a big pest in the United States. Back then, they cost ranchers and dairy farmers about $200 million each year, according to government statistics. (That would equal about $1.8 billion today.)

These flies lay their eggs in tiny wounds on cattle. Soon afterward, fly larvae hatch and begin eating. If the cattle aren’t treated, the insects can cause infections that bring down an adult cow in fewer than two weeks. A calf can die even more quickly.

Researchers who studied screwworm flies found out that a female mates only once in her life. So, they came up with a neat idea: If the only males available to young female flies were sterile — unable to fertilize eggs — then there would never be a new generation of flies. Populations would drop and the pests could be eradicated.

The original research projects only cost about $250,000 and were spread over several decades. But that research has saved U.S. ranchers and dairy farmers, alone, billions of dollars over the past 50 years, notes Brennan. Those flies are no longer a U.S. plague.

“Ahead of time, it’s tough to predict which projects will be successful,” Brennan points out. Indeed, potential applications of research often are unknown. But every successful project derives from the results of simple projects, such as the details of how an animal reproduces.  So even research that may seem silly, she argues, can sometimes pay off big.

Power Words

(more about Power Words)

annual     Adjective for something that happens in every year. (in botany) A plant that lives only one year, so it usually has a showy flower and produces many seeds.

application     A particular use or function of something.

aquatic     An adjective that refers to water.

behavior     The way a person or other organism acts towards others, or conducts itself.

biology     The study of living things. The scientists who study them are known as biologists.

calf     (plural: calves) The name of young animals in a range of mammalian species, from cattle to walruses.

cattle     Also known as bovines (because they’re members of the subfamily known as Bovinae), these are breeds of livestock raised as a source of milk and meat. Although the adult females are known as cows and the males as bulls, many people refer to them all, generally, as cows.

crustaceans     Hard-shelled water-dwelling animals including lobsters, crabs and shrimp.

dairy     Containing milk or having to do with milk. Or a building or company in which milk is prepared for distribution and sale.

developing world     A region with relatively little industry and a lower standard of living than industrial countries, such as the United States, Germany and Japan.

evolutionary biologist     Someone who studies the adaptive processes that have led to the diversity of life on Earth. These scientists can study many different subjects, including the microbiology and genetics of living organisms, how species change to adapt, and the fossil record (to assess how various ancient species are related to each other and to modern-day relatives).

fertilize     (in biology) The merging of a male and a female reproductive cell (egg and sperm) to set in create a new, independent organism. (in agriculture and horticulture) To provide basic chemical nutrients for growth.

generation     A group of individuals born about the same time or that are regarded as a single group. Your parents belong to one generation of your family, for example, and your grandparents to another. Similarly, you and everyone within a few years of your age across the planet are referred to as belonging to a particular generation of humans. The term also is sometimes extended to year classes or types of inanimate objects, such as electronics or automobiles.

germ     Any one-celled microorganism, such as a bacterium, fungal species or virus particle. Some germs cause disease. Others can promote the health of higher-order organisms, including birds and mammals. The health effects of most germs, however, remain unknown.

hormone     (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.

immune system     The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.

infection     A disease that can spread from one organism to another. It’s usually caused by some sort of germ.

insect     A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.

marine biologist     A scientist who studies creatures that live in ocean water, from bacteria and shellfish to kelp and whales.

motor     A device that converts electricity into mechanical motion. (in biology) A term referring to movement.

organ     (in biology) Various parts of an organism that perform one or more particular functions. For instance, an ovary is an organ that makes eggs, the brain is an organ that interprets nerve signals and a plant’s roots are organs that take in nutrients and moisture.

Pacific     The largest of the world’s five oceans. It separates Asia and Australia to the west from North and South America to the east.

plastic     Any of a series of materials that are easily deformable; or synthetic materials that have been made from polymers (long strings of some building-block molecule) that tend to be lightweight, inexpensive and resistant to degradation.

population     (in biology) A group of individuals from the same species that lives in the same area.

prey     (n.) Animal species eaten by others. (v.) To attack and eat another species.

sex     An animal’s biological status, typically male or female. There are a number of indicators of biological sex, including sex chromosomes, gonads, internal reproductive organs, and external genitals.

species     A group of similar organisms capable of producing offspring that can survive and reproduce.

statistics     The practice or science of collecting and analyzing numerical data in large quantities and interpreting their meaning. Much of this work involves reducing errors that might be attributable to random variation. A professional who works in this field is called a statistician.

sterile     An adjective that means devoid of life — or at least of germs. (in biology) An organism that is physically unable to reproduce.

warm-blooded     Adjective for animals (chiefly mammals and birds) that maintain a constant body temperature, typically above that of their surroundings. Scientists generally prefer the term endothermic to describe animals that generate heat to control their body’s temperature.


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P. Brennan. “What scientists – and the scientific community – should do when grants are challenged.” American Association for the Advancement of Science Meeting. February 18, 2017. Boston, Mass.

D. Scholnick. “How a $47 shrimp treadmill became a $3 million political plaything.” American Association for the Advancement of Science Meeting. February 18, 2017. Boston, Mass.