Cara Giaimo

If you want to run a successful business, it’s important to provide a valuable service, advertise it well and do your best to get out what you put in. You should also try to make sure your customers don’t eat you.

This is especially true if you’re a cleaner shrimp. These industrious crustaceans set up cleaning stations — grooves in rocks in which they can retreat — in tropical coral reefs, where they pick parasites and dead skin off the fish, eels and turtles that seek them out for this purpose.

It’s a nutritious but dangerous job. Some of these clients — that’s the scientific term — are many times the shrimp’s size. And if such a client is hungry, it might start to see the little guy crawling all over it as less of a helper, and more of a snack.

What’s a hardworking shrimp to do? According to a paper published this week in Biology Letters, one species has a strategy: Choose your clients carefully and, when necessary, do a funky dance.

Eleanor Caves, a postdoctoral bioscientist at the University of Exeter and the paper’s lead author, has been puzzled by cleaner shrimp for years. Although the shrimps’ bright colors and tank maintenance skills make them popular aquarium pets, they are “highly understudied” in the wild, she said.

The relationship between cleaner shrimp and their clients is generally considered a mutualism: an association between two species where both benefit. In this case, the shrimp gets a meal, and the fish gets a touch-up. Other mutualistic teams include ants and acacia trees, pollinators and flowers, and anemones and clown fish.

But it’s more difficult to understand teamwork between cleaner shrimp and, say, goatfish, which Caves said are known to “gobble crustaceans.”

“It’s hard to know how such a system could evolve,” she said. “The cleaner shrimp should really not be cleaning at all, because they ought to just get eaten.”

In this study, Caves and her colleagues focused on a hard-to-find species, Lysmata amboinensis, or the Pacific cleaner shrimp. The team located two shrimp-staffed cleaning stations on a reef in the Red Sea near Eilat, Israel, and trained cameras on them.

After filming and watching 242 fish visits, they noticed that the cleaner shrimp turned down potentially predatory clients 75% of the time — far more often than they did harmless ones. Fair enough.

But when a shrimp did take on a scarier client, it often began the interaction with a signal: It would bend its front legs and waving them back and forth. Pacific cleaner shrimp have white front legs that contrast with the rest of their body; in videos, it looks like they’re performing a color guard solo. “It’s amazing how much it stands out, even at depth,” Caves said.

The researchers then exposed cleaner shrimp in their lab to various silhouettes meant to represent clients of different sizes. The shrimp leg-waved in response to shapes that blocked out more light, as a larger fish would.

“It kind of looked like they were like, ‘Oh no!’” said Catherine Chen, an author of the paper, who designed this part of the experiment while she was an undergraduate at Duke University. “And then they’d do their little leg thing and be fine.”

The experiment joins a few others that have sought to uncover how these shrimp are able to work with clients across a stark power differential. The researchers have “confirmed that some cleaner shrimps are able to show discrimination in their cleaning service,” and introduced the idea that a client’s size might inspire the decision to signal, said Lucille Chapuis, a postdoctoral researcher at the University of Exeter who was not involved in the paper but has studied comparable behavior in other cleaner shrimp species.

Signaling may also help to explain another mystery: why cleaner shrimp look so flashy when they themselves are colorblind. All those bright hues and patterns may be necessary to get a message across to fish that differentiates the shrimp from prey, Caves said. Perhaps it’s what customer service looks like when your life depends on it.

This article originally appeared in

It's a Dirty Job, but Someone Has to Do It and Not Get Eaten

(Trilobites)

If you said Tom, congratulations! You just demonstrated what’s called “transitive inference” — the ability to compare things indirectly, based on previous juxtapositions. But before you pat yourself on the back too much, you should know that this skill was recently demonstrated by another creature:the humble paper wasp that might be living in your backyard right now.

In the summer of 2017, researchers at the University of Michigan put two species of paper wasps through a transitive inference test. A statistically significant portion of the time, the wasps passed. Other animals — including rats, geese and cichlid fish — have also exhibited this capacity. But this study, which was published Tuesday in Biology Letters, is the first to successfully showcase it in an invertebrate (honeybees failed a similar test in 2004).

Paper wasps are found on every continent except Antarctica. You might be near some right now. “They tend to nest in the eaves of houses, or inside barbecue grills,” said Elizabeth Tibbetts, the study’s lead author.

In a previous study, Tibbetts showed that individual female wasps can identify one another by their distinct facial patterns, which resemble Rorschach ink blots. “When two wasps meet, they learn, ‘Oh, that’s what Suzy looks like,’” she said. “And the next time they meet, they remember who Suzy is.”

In the spring, the females spend a lot of time brawling, getting in each other’s faces and trading slaps with their appendages. These matchups look like schoolyard tussles. “Some wasps will be fighting; some wasps will be watching the fights,” Tibbetts said. “It’s a very exciting time.” The wasps remember the winners and losers, and use them to establish a social hierarchy: the strongest reproduce, while the weaker ones do all the work.

Tibbetts and her colleagues wanted to see whether the wasps could take this a step further. Say a particular paper wasp beat Suzy, and then was ringside a few days later when Suzy walloped Jane. Could that wasp figure out that she’d probably best Jane, too?

Such knowledge would require transitive inference. So the team turned to what’s called a “five-element training procedure,” now a standard way to test this skill in animals. They put the wasps in a series of bi-colored chambers. If they moved toward the wrong color, they got a mild electric shock. In this way, “you train them that blue is better than green, and once they learn that, you train them that green is better than purple,” said Tibbetts. They did this for four pairs of five colors.

After the wasps had been trained, they were put in a new chamber. This one had colors they were familiar with from the training, but hadn’t been paired up before. About 67% of the time, the wasps successfully chose the “better” color — the one less likely to shock them.

“They are organizing all those pairs into a linear hierarchy in their head,” Tibbetts said. Next, she plans to study how the wasps actually use this ability during social interactions.

Colin Allen, a cognitive philosopher at the University of Pittsburgh, cautions against over-interpreting the study, saying the simplicity of the test makes it “hard to judge what processes are operating in these wasps.” But he calls it “an important reminder” that just because bees can’t do something, doesn’t necessarily mean that no insects can.

It fits well with another of the study’s lessons: Just because humans can do something, doesn’t necessarily mean that all insects can’t.

This article originally appeared in <a id="708cd278-5b93-3614-a87f-fb9618bdf7bd" href="https://www.nytimes.com/2019/05/09/science/paper-wasps-logic-test.html">The New York Times</a>.

Here’s a pop quiz for you. Tom is taller than Dick. Dick is taller than Harry. Who’s taller, Harry or Tom?

Wasps passed this logic test, can you?

A young ostrich sprints down a path at a Chinese farm. His neck bobs, his legs pump — and the artificial wings attached to his back flap up and down.

Alas, this ostrich will not fly. He’s filling in for another earthbound creature, a dinosaur called Caudipteryx. Some 125 million years ago, this theropod walked on two legs and bore a pair of feathery “proto-wings,” similar to the fake ones worn by the ostrich. Recently, researchers set out to study the long-extinct creature as they took on one of the greatest controversies in paleontology: how avian flight first evolved.

In a study published Thursday in PLOS Computational Biology, a team including mechanical engineer Jing-Shan Zhao and several paleontologists used the outfitted ostrich — along with mathematical and robot models — to argue that when Caudipteryx ran, its mini-wings flapped involuntarily. Eventually, the researchers proposed, the dinosaur’s descendants would have harnessed this trait and taken off from the ground for the first time.

Other experts are less than convinced, arguing that the study’s analogues don’t do justice to the complexity of the animal it purports to study. But the disagreement itself highlights the unsettled nature of debates over the evolution of flight among the world’s feathered inhabitants.

“You’d be hard-pressed to find a paleontologist who doesn’t have an opinion,” said Armita Manafzadeh, a doctoral student at Brown University who was not involved in the study.

Because modern birds evolved from a particular lineage of dinosaurs, the theropods, researchers look to them to figure out how flight began. Some promote a “top-down” theory, contending that winged dinosaurs learned to fly by climbing trees and gliding from the branches, not unlike flying squirrels. Others are on the “ground-up” side, positing that dinosaurs went airborne by running and flapping. Still others question the dichotomy itself, arguing that the two theories are not mutually exclusive.

For their entrance into the fray, Zhao’s group performed three experiments. All focused on Caudipteryx, a useful organism for studying “the evolution from the earliest dinosaur to the modern bird,” said Zhao, who teaches at Tsinghua University in Beijing. Caudipteryx was discovered in China in the late 1990s, and, in renderings, often resembles an angry, oversized chicken.

For the first experiment, the group used fossil analyses to develop a simplified mathematical model of the dinosaur. They then simulated a running motion in the model’s legs, and calculated how other parts of the body responded. They found that at a fast enough clip — between 5.5 and 12.9 mph, a range within Caudipteryx’s estimated capability — the model’s wings flapped.

For the second test, they built a robo-Caudipteryx and ran it on a treadmill. Here, too, they observed consistent oscillation, even as they increased and decreased wing length.

Then it was time for a live test. Zhao and his colleagues built a harness with force sensors and a set of wings. They augmentedmany birds, including ducks and geese, before settling on a 6-month-old ostrich.

“Its size and weight looked like the real size and weight of Caudipteryx,” Zhao said. (Because living dinosaurs aren’t available for paleontology studies, their descendants, from baby partridges to chickens with prosthetic tails, often serve as proxies.)

As the ostrich ran, flapping was evident, and the sensors measured a small amount of lift: The motion was counteracting some of the bird’s body weight. Zhao suggests that Caudipteryx might have noticed that the weird thing its wings were doing was actually making it easier to run, and leaned into it. In this way, the passive jostling provided “basic training for later flapping flight,” he said.

Is it conclusive proof that flapping came first? Other researchers, though impressed by the study’s three-pronged approach, expressed doubts.

Dennis Voeten, who studies flying dinosaurs at the European Synchrotron Radiation Facility, in France, and Sweden’s Uppsala University, thinks the group’s conclusions went too far. Observing oscillation “does not prove that this dynamic ‘trained’ early feathered dinosaurs in executing a birdlike flapping motion,” he said. Manafzadeh added that simplifying dinosaur anatomy has its pitfalls, as does using passive, plastic wings to stand in for active limbs.

Zhao responded that the benefits of flapping should have been enough to nudge evolution in that direction, and that the group’s experiments left room for various anatomical considerations.

“You can change the mass, or the stiffness of the muscles, anything,” he said. “The flapping motion will not change.”

This article originally appeared in <a href="https://www.nytimes.com/2019/05/02/science/dinosaurs-wings-birds.html" id="144f6f0e-2d4f-3fc3-a83d-4ea2500a36d8">The New York Times</a>.

Why Is This Ostrich Wearing an Extra Set of Wings?

Can you remember what you did yesterday? If not, you might want to take a lesson from Nasa poissoniana, a star-shaped flowering plant from the Peruvian Andes with an unusual skill set.

These plants can gymnastically wave around their stamens — the organs they use for fertilization — to maximize the distribution of their pollen. More surprisingly, a study published in March in Plant Signaling and Behavior suggests that individual plants can adjust the timing of these movements based on their previous experiences with pollinators. In other words, they remember the past, and try to repeat it.

The discovery joins others recently painting an ever-broader picture of what plants can sense, learn and do. The study, although small and preliminary, “presents a promising and intriguing new system to study plant memory,” said Peter Crisp, a plant geneticist at the University of Minnesota who was not involved in the study.

Nasa poissoniana belongs to a subfamily of plants called Loasoideae. They’re known for their polychrome blooms, as well as for the “really painful” stinging hairs on their stems, said Tilo Henning, one of the study’s lead authors.

Henning, a researcher at the Botanic Garden and Botanical Museum in Berlin, has been working with Loasoideaefor nearly two decades, along with his collaborator Maximilian Weigend of the University of Bonn in Germany. From the start, “the complexity of the flowers thrilled us,” he said. So did their tendency toward thigmonasty, or triggered movement.

While other plants may curl their leaves or catapult their seeds, many species of Loasoideaemove their stamens: long, skinny filaments that are capped with pollen. Loasoideaestamens start out splayed, bunched up in groups and tucked within the flower’s petals. Over the course of the flower’s life, the individual stamens swing one by one into the center of the flower, where they stand tall and offer fresh pollen to insect visitors.

It takes less than three minutes for a Loasoideae stamen to travel from the outside in — nimble by plant standards. In certain species, this movement can be provoked by light and temperature, or by the pollinators themselves. When a bee rummages around for nectar in the flower’s center, it triggers the next stamen to come sweeping in, ready for a new bee, or the previous bee’s return. In this way, the flowers maximize their chances of transferring pollen to many different flowers.

For this latest study, the researchers divided Nasa poissonianainto several groups. “Pollinators” — in this case, humans with probes — visited the first group every 15 minutes, rustling the flowers’ nectar-containing parts. They bothered the second group every 45 minutes. Other groups were left alone, as controls.

The next day, the researchers observed the flowers. Those that had been visited every 15 minutes planned for that timeline, swinging in new stamens faster and more often. The second group was more lackadaisical, and its fresh stamen concentration peaked at the 45-minute mark. The plants were “anticipating pollinator revisits,” said Henning, who expects that other members of Loasoideae also have this talent.

Heidi Appel, a plant behaviorist at the University of Toledo, said the study “provides another great example of how exquisitely tuned plants are to their environment.” But she stopped short of using the word “intelligent,” or other terms that might anthropomorphize plant behavior.

Whether you apply such adjectives to these plants or not, Henning said he wants to know why they try so hard.

“The tremendous overall expenditure these plants invest in” spreading their pollen around is puzzling, he said. “There are a number of similar successful plant groups. But none of them shows such an elaborate effort.”

Watch a Flower That Seems to Remember When Pollinators Will Come Calling

Watch a flower that seems to remember when pollinators will come calling

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