Northern pike attacks crayfish


This 13 November 2019 video shows a northern pike attacking a crayfish.

Diver Freddy van Tuil in the Netherlands made this video.

How mantis shrimp think, new research


This 2013 video says about itself:

World’s Fastest Punch | Slow Motion Mantis Shrimp | Earth Unplugged

The peacock mantis shrimp has the world’s fastest feeding strike of any animal. Can Sam and Si capture this lightning-fast punch?

From the University of Arizona in the USA:

How mantis shrimp make sense of the world

November 25, 2019

A study involving scientists at the University of Arizona and the University of Queensland provides new insight into how the small brains of mantis shrimp — fierce predators with keen vision that are among the fastest strikers in the animal kingdom — are able to make sense of a breathtaking amount of visual input.

The researchers examined the neuronal organization of mantis shrimp, which are among the top predatory animals of coral reefs and other shallow warm water environments.

The research team discovered a region of the mantis shrimp brain they called the reniform (“kidney-shaped”) body. The discovery sheds new light on how the crustaceans may process and integrate visual information with other sensory input.

Mantis shrimp sport the most complex visual system of any living animal. They are unique in that they have a pair of eyes that move independently of each other, each with stereoscopic vision and possessing a band of photoreceptors that can distinguish up to 12 different wavelengths as well as linear and circular polarized light. Humans, by comparison, can only perceive three wavelengths — red, green and blue.

Therefore, mantis shrimp have much more spectral information entering their brains than humans do. Mantis shrimp seem to be able to process all of the different channels of information with the participation of the reniform body, a region of the animal’s brain found in the eyestalks that support its two protruding eyes.

Researchers Hanne Thoen and Justin Marshall at Queensland Brain Institute at the University of Queensland in Brisbane, Australia, teamed up with Nicholas Strausfeld at the University of Arizona, as well as scientists from Lund University in Sweden and the University of Washington in the U.S. to gain a better understanding of how the reniform bodies connect to other parts of the mantis shrimp brain and gather clues to their functional roles.

Using a variety of imaging techniques, the team traced connections made by neurons in the reniform body and discovered that it contains a number of distinct, interacting subsections. One particular subunit is connected to a deep visual center called the lobula, which is structurally comparable to a simplified visual cortex.

“This arrangement may allow mantis shrimp to store quite high-level visual information,” said Strausfeld, senior author of the paper that was published in the Journal of Comparative Neurology.

“Mantis shrimp most likely use these subsections of the reniform body to process different types of color information coming in and organize it in a way that makes sense to the rest of the brain,” said lead author Thoen. “This would enable them to interpret a large amount of visual information very quickly.”

One of the study’s crucial findings was that neural connections link the reniform bodies to centers called mushroom bodies, iconic structures of arthropod brains that are required for olfactory learning and memory.

“The fact that we were now able to demonstrate that the reniform body is also connected to the mushroom body and provides information to it, suggests that olfactory processing may take place in the context of already established visual memories,” said Strausfeld, Regents Professor of neuroscience and director of the Center for Insect Science at the University of Arizona.

The discovery of the reniform body, however, is not limited to mantis shrimp. It has been identified in other species as well, including shore crabs, shrimp and crayfish.

In 2016, an Argentinian group discovered that, in crabs, what are now known as reniform bodies act as secondary centers for learning and memory. According to Strausfeld, this suggests that the formation and storage of memories occurs in at least two different and discrete sites in the brain of the mantis shrimp and likely other members of malacostracans, the largest class of crustaceans. In addition to mantis shrimp, malacostracans include crabs, lobsters, crayfish, shrimp, krill and other less familiar species that together account for about 40,000 living species and a great diversity of body forms.

Reniform bodies have not been identified in insects and may be uniquely crustacean attributes, the researchers say. Alternatively, they might be homologous to a structure found in insect brains called the lateral horn, which sits between the optic lobes and the mushroom bodies. Strausfeld pointed out that fruit fly research done by other groups showed that the lateral horn is crucial in assigning values to learned olfactory information.

“The hunt is now on to determine if insects have a homologous center,” he said. “If we are looking for homologs in other arthropods, the reniform body would be the obvious candidate.”

The study was funded in part by the Asian Office of Aerospace Research and Development (12?4063), the Australian Research Council (FL140100197) and the National Science Foundation (11754798).

Disco clams and mantis shrimp, new research


This August 2016 video says about itself:

Ctenoides ales, also known as the “electric disco clam“, is lighting up tropical waters with its resemblance to a flashing neon light.

From the University of Colorado at Boulder in the USA:

Mantis shrimp vs. disco clams: Colorful sea creatures do more than dazzle

November 18, 2019

Summary: A researcher encountered a colorful creature called a disco clam in an Indonesian reef. Now, recent research suggests that she may be narrowing in on answering why this bivalve looks so wild.

When Lindsey Dougherty was an undergraduate student at CU Boulder in 2011, she got the chance to visit North Sulawesi, Indonesia, on a research trip. There, in the clear tropical waters off the coast, she encountered an animal that would change the course of her career.

It was the disco clam (Ctenoides ales). And it caught Dougherty’s eye for good reason: Even in a coral reef, these tropical bivalves are explosions of color. They have bright-red appendages that dangle out of their shells and thin strips of tissue that pulse with sparkly light like a disco ball — hence their name.

In that moment, she found her research calling.

“How do they flash?'” Dougherty remembered thinking as she dove through the reef with scuba gear.

As a graduate student at the University of California, Berkeley, the young scientist solved that first puzzle: the clams, she discovered, carry tiny, silica spheres in their tissue.

Now back in Colorado as an instructor in the Department of Ecology and Evolutionary Biology (EBIO), Dougherty is pursuing an even trickier mystery: Why are these bivalves so colorful in the first place?

The answer could reveal new clues to how the interaction between species drives the evolution of ocean animals over millions of years.

It’s a pursuit that has expanded to include several high school students and introduced Dougherty to an animal that may be even more groovy-looking than the disco clam — a fierce predator on the same coral reefs called the peacock mantis shrimp (Odontodactylus scyllarus).

This 2016 video from a German aquarium is about a peacock mantis shrimp.

And in a recently published paper in the journal Royal Society Open Science, she and her colleagues report that they may be finally getting close to solving that puzzle.

“It’s a long time to spend on one organism,” Dougherty said. “But I think it also shows how many questions there are about one seemingly simple clam.”

Clams vs. mantis shrimp

To grasp Dougherty’s obsession with this shelled organism, it helps to understand the weirdness of the disco clam.

Jingchun Li is a curator of invertebrates at the CU Museum of Natural History and advised Dougherty during her postdoctoral studies at CU Boulder. Li has spent her career exploring the diversity of the world’s bivalves — a class of aquatic mollusks that include animals like clams, scallops and mussels.

“Normally, if you think about clams like the ones in clam chowder — they’re little white things,” said Li, also an assistant EBIO professor. “But these clams are so colorful. One hypothesis we had is this might be some sort of warning signal to predators saying, ‘Don’t eat me.'”

In other words, disco clams might taste really bad, and they advertise that to the world using their bright colors. Kind of like a coral reef version of poison dart frogs in the Amazon.

To test that idea, Li and Dougherty recruited several peacock mantis shrimp — which, despite their names, aren’t actually shrimp — and kept them in tanks on the CU Boulder campus.

Like disco clams, these animals are pretty wild to look at. They come in a rainbow of colors, from blues and greens to neon orange and yellow. But don’t let their appearance fool you. Known for their powerful punches, mantis shrimp can extend their front claws at speeds of nearly 75 miles per hour — fast enough to generate an underwater shock wave that can shatter aquarium glass on impact.

The researchers, in other words, set up an ecological contest between the colorful mantis shrimp and flashing clams.

They offered their mantis shrimp a choice between two types of disco clam tissue. The mantis shrimp could either eat bright-red meat from the clams’ exterior or normal, white meat from their inner muscles.

The mantis shrimp didn’t even hesitate. They went for the white meat.

“It turns out they really hate the red tissue,” Li said.

That, along with chemical analyses of the two types of meat, certainly seemed to suggest that the team’s poison dart frog hypothesis had been spot on.

But another wrinkle emerged: When the group offered the mantis shrimp white meat that was dyed to look red, the invertebrates still chowed down.

As Dougherty put it, “Whether or not the red color is a warning needs more research.”

Vinegar vs. Sriracha

It’s work that’s happening now in Li’s lab. She’s hoping to discover whether the same mantis shrimp can learn to fear the color red — a key step in determining whether that shade may act as a warning signal.

Aiding Li in that effort are two seniors from Monarch High School in Louisville, Colorado, who are helping out in her lab through the Science Research Seminar program in the Boulder Valley School District. They’re tackling a pretty basic question: What kinds of food taste gross to a mantis shrimp?

The students, Grateful Beckers and Elysse DeBarros, have spent their semester trying out different flavor combinations, which they add to chunks of supermarket shrimp meat. Once they find a suitably yucky taste, they’ll mix it with meat dyed red to see if mantis shrimp will become wary of that hue over time.

Early results suggest that mantis shrimp can’t stand the taste of vinegar but, like many people, don’t seem to mind Sriracha sauce.

“They’re so unique,” Beckers said. “They’re a large, interesting shrimp with a lot of interesting adaptations.”

Dougherty herself may still have a way to go before she resolves the mystery that first caught her attention on the Indonesian reef all those years ago. But it’s been a fascinating road of discovery for this Colorado native who first learned to scuba dive in the Pueblo Reservoir.

“I love the mountains, and I love diving. I don’t think they should ever be mutually exclusive,” Dougherty said. “Everyone is connected to the ocean whether they realize it or not.”

Other coauthors on the new research included Alexandria Niebergall of UC Berkeley, Corey Broeckling of Colorado State University and Kevin Schauer of the University of Wisconsin-Madison.

Butterflies, lobsters threatened by climate change


This 18 July 2014 video from England says about itself:

One of Britain’s rarest butterflies, the Silver-studded Blue, is being reintroduced on National Trust land at Black Down, West Sussex, in a bid to help safeguard its future.

The Silver-studded Blue has declined rapidly over the past few decades and can now only be seen in small colonies on heathland in the south of England and on some coastal limestone grasslands and dune systems.

Black Down was identified as a suitable habitat for the Silver-studded Blue following a heathland restoration project which took 12 years to complete. Carried out by National Trust rangers and volunteers, the work restored the land to open heath complete with a canvas of purple heather attracting walkers who can experience uninterrupted views across the South Downs.

From the University of York in England:

Scientists identify British butterflies most threatened by climate change

October 24, 2019

Scientists have discovered why climate change may be contributing to the decline of some British butterflies and moths, such as Silver-studded Blue and High Brown Fritillary butterflies.

Many British butterflies and moths have been responding to warmer temperatures by emerging earlier in the year and for the first time scientists have identified why this is creating winners and losers among species.

The findings will help conservationists identify butterfly and moth species most at risk from climate change, the researchers say.

The study, led by the University of York, found that emerging earlier in the year may be benefitting species which have multiple, rapid breeding cycles per year and are flexible about their habitat (such as the Speckled Wood butterfly), by allowing them more time to bulk up in numbers before winter and expand their range towards the north.

In contrast, early emergence may be causing species that are habitat specialists and have only a single life-cycle per year, to shrink in numbers and disappear from northern parts of the country within their historical range.

Single generation species that are habitat specialists (like the rare High Brown Fritillary butterfly) are most vulnerable to climate change because they cannot benefit from extra breeding time and emerging earlier may throw them out of seasonal synchrony with their restricted diet of food resources, the researchers suggest.

The researchers studied data on butterflies and moths, contributed by citizen scientists to a range of schemes including Butterflies for the New Millennium and the National Moth Recording Scheme (both run by Butterfly Conservation), over a 20 year period (1995-2014) when the average spring temperatures in Britain increased by 0.5 degrees.

Temperature increases are causing butterflies and moths to emerge on average between one and six days earlier per decade over this time period.

Lead author of the study, Dr Callum Macgregor, from the Department of Biology at the University of York, said: “Because butterflies in general are warmth loving, scientists predicted that the range margin of most species would move north as a result of global heating. However this hasn’t happened as widely or as quickly as expected for many species.

“Our study is the first to establish that there is a direct connection between changes in emergence date and impacts on the habitat range of butterflies and moths. This is because emerging earlier has caused some species to decline in abundance, and we know that species tend only to expand their range when they are doing well.”

Professor Jane Hill, from the Department of Biology at the University of York, who leads the NERC Highlight project, said: “Our results indicate that while some more flexible species are able to thrive by emerging earlier in the year, this is not the case for many single generation species that are habitat specialists — these species are vulnerable to climate change.”

Co-author Professor Chris Thomas, from the Leverhulme Centre for Anthropocene Biodiversity at the University of York, added: “These changes remind us how pervasive the impacts of climate change have already been for the world’s biological systems, favouring some species over others. The fingerprint of human-caused climate change is already everywhere we look.”

Professor Tom Brereton of Butterfly Conservation said: “The study shows that we urgently need to conduct ecological research on threatened butterflies such as the High Brown Fritillary, to see if we can manage land in a new way that can help them adapt to the current negative effects of climate change.”

Climate-induced phenology shifts linked to range expansions in species with multiple reproductive cycles per year is published in Nature Communications.

This study was carried out in collaboration with researchers at the universities of Bristol, Liverpool, Melbourne (Australia) and Stockholm (Sweden), in addition to researchers at Butterfly Conservation; the Centre for Ecology & Hydrology; Rothamsted Research; and the Natural History Museum. The research was supported by a grant from the Natural Environment Research Council.

This 2015 video from the USA says about itself:

Northern Lobsters of Maine | JONATHAN BIRD’S BLUE WORLD

In the north Atlantic, the American Lobster is the undisputed king of crustaceans. It’s also a tremendously important commercial catch.

Two new studies published by University of Maine scientists are putting a long-standing survey of the American lobster‘s earliest life stages to its most rigorous test yet as an early warning system for trends in New England’s iconic fishery. The studies point to the role of a warming ocean and local differences in oceanography in the rise and fall of lobster populations along the coast from southern New England to Atlantic Canada: here.

Two new porcelain crab species discovery


This April 2018 video says about itself:

Species Corner – Porcelain crab in a symbiotic relationship with a bubble-tip anemone

The Porcelain Crab is common throughout the tropical oceans of the world, and has a flat, round body with two large front claws. They are brown and orange in coloration with bright blue spots. These crabs have a pair of front arms called maxillipeds, which have ends that are feather-like in appearance. They use these appendages to filter the water for any passing food. They are peaceful and interesting invertebrates for the marine aquarium..

From the Smithsonian Tropical Research Institute:

Two new porcelain crab species discovered

October 15, 2019

Summary: Two new symbiotic porcelain crab species have been described. One of them, from the South China Sea of Vietnam, inhabits the compact tube-like shelters built by the polychaete worm with other organisms. The other inhabits the intertidal vermetid snail formations in the Colombian Caribbean.

Two new porcelain crab species have been described in the ZooKeys journal by scientists from the Smithsonian Tropical Research Institute (STRI) and the Institut fur Tierokologie und Spezielle Zoologie der Justus-Liebig-Universitat Giessen. One of the new species, Polyonyx socialis, was discovered in the South China Sea of Vietnam. The other, Petrolisthes virgilius, has a new identity, after initially being taken for a similar-looking species — Petrolisthes tonsorius — four decades ago in the Colombian Caribbean.

Porcelain crabs belong to a highly diverse family of marine crustaceans, distributed in the shallow waters of oceans worldwide. They also are known as “false crabs”, because they evolved a crab-like form independently of true crabs. A relatively large number of porcelain crab species are symbiotic with other organisms, allowing scientists to tell a story of a long-time relationship between species from distantly related taxa.

“Most porcelain crabs live on the hard substrates of shallow waters like the surface of corals or rocks overgrown by algae, microbes and decaying material,” said STRI research associate Alexandra Hiller, co-author of the papers. “Others live as symbionts of invertebrates like sponges, anemones, sea urchins, polychaete worms and other crustaceans.”

The two recently described species are examples of these symbiotic porcelain crabs. P. socialis derives its name from the Latin word for “social” because it was found living with other organisms — including the larger porcelain crab species, Polyonyx heok — in the compact tube-like shelters built by the polychaete worm Chaetopterus sp. Its broad, flat walking legs and claw-bearing extremities appear to have been adapted for living tightly-attached to the worm tube walls and avoid being perceived as an obstacle for the other organisms.

Although initially mistaken for P. tonsorius in the 1970s, the uncommon colors and atypical habitat of P. virgilius — intertidal vermetid snail formations in the Colombian Caribbean — led the scientists to corroborate through genetic analyses that it was a new species. As a symbiont, P. virgilius has evolved in tight association to its distinctive surroundings: a reef-like microhabitat exposed to wave action and consisting of snail shells cemented to each other and to a hard substrate.

Despite the relatively high number of known symbiotic porcelain crab species, such as P. socialis and P. virgilius, the researchers believe this aspect of their ecology could hinder their long-term survival, particularly in the shallow-water ecosystems where they typically occur. These habitats are often more vulnerable to climate change, ocean acidification and contamination.

“Symbiotic species are thought to be more vulnerable to environmental challenges than free-living organisms,” said Prof. Dr. Bernd Werding, from the Institut fur Tierokologie und Spezielle Zoologie der Justus-Liebig-Universitat Giessen, and co-author of the studies. “Their fate depends on the fate of their host, which may also be affected by local and global conditions and abrupt changes.”