Aroma Pets

The Evolution of Flight Behavior in Butterflies

According to research, non-edible butterfly species that imitate one another's color patterns have developed comparable flight movements as a means of alerting predators and evading extinction.

 team looked specifically at a tribe of butterflies called the Heliconiini. Image Credit: University of York© Provided by AZoLifeSciences

It is commonly recognized that a large number of non-edible butterfly species have developed nearly identifiab{youtube}le color patterns that serve as alerts to potential predators, preventing the butterflies from being consumed.

It has now been demonstrated by researchers at the University of York that these butterflies have developed identical flight patterns in addition to similar color patterns, which combined provide a more potent warning to potential predators.

Researchers at the University of York measured the wing beat frequency and wing angles of 351 butterflies, representing 38 species that fall into one of ten different color pattern mimicry groups. They did this by using high-speed video footage to capture the flight of natural butterflies in South America.

Using this dataset, scientists looked into the relationships between habitat, wing shape, temperature, and the color pattern of the butterfly's “mimicry group” to determine which characteristics had the greatest impact on the butterfly's flight behavior.

The researchers discovered that contrary to expectations, the color pattern mimicry group a butterfly belonged to was the primary determinant of its flight behavior, even if the species’ habitat and wing shape also played a significant role.

This indicates that compared to closely related species that exhibit distinct warning coloring, distantly related butterflies that belong to the same color pattern mimicry group have more similar flight behavior. The butterflies would appear identcal to a predator due to their color patterns, and they would likewise move in a similar way.

Nasty Taste

From an evolutionary perspective it makes sense to share the color pattern between species, to reduce the individual cost of educating predators to the fact that they do not taste nice! Once a predator has tasted one, the visual clues on others indicate that they too are also inedible, but flight patterns are more complex and are influenced by several other factors such as the air temperature and the habitat the species fly in.”

Edward Page, PhD Student and Study Lead Co-Author, Department of Biology, University of York

Edward Page said, “We wanted to see whether flight corresponded to color - could predators be driving the mimicry of flight as well as color patterns? We were surprised to find just how strong and widespread the behavioral mimicry is.”

70 Million Years Ago

The researchers focused on the Heliconiini, a tribe of butterflies found in the Neotropics that comprise over 100 species and subspecies, all of which belong to different groups that replicate different color patterns.

Additionally, they looked into a few species of ithomiine butterflies, which broke away from the Heliconiini some 70 million years ago but share striking similarities in their "Tiger" color patterns.

Sharing flight behavior across multiple species seems to reinforce this ‘do not eat me’ message. It is fascinating that this behavior has evolved between distant relatives over a long period of time, but we can also see flight behavior diverging between differently patterned populations within a species over a relatively short period of time too."

Edward Page, PhD Student and Study Lead Co-Author, Department of Biology, University of York

Subtle Changes

The extent of flight mimicry in this group of butterflies is amazing. It is a great example of how evolution shapes behavior, with selection from predators driving subtle changes which enhance the survival of individuals and the challenge and interest now is to identify the genes causing these changes, which will tell us how such behavioral mimicry evolves.”

Reference: Azo Life Sciences: Kanchon Dasmahapatra, Professor, Department of Biology, University of York

What Animals Teach Us About Health and the Science of Healing

“Obesity is a disease of the environment.”— Richard Jackson - Health

Barbara Natterson-Horowitz, a cardiologist at the University of California Los Angeles, believes that her fellow human physicians have much to learn from their veterinary counterparts. These are not separate fields, she argues in her book, coauthored with science writer Kathryn Bowers, Zoobiquity: What Animals Can Teach Us About Health and the Science of Healing.

Did you know that animals get cancer? heart disease? They also faint. Even diseases we think of as uniquely human, like depression, sexual performance, and addiction are found in the animal world. A lot of animals even self-injure when faced with stress or boredom.

When asked, “why should doctors listen to veterinarians,” in a recent interview she responded:

I can speak from my own personal experience. I had spent almost a couple decades being a human doctor, a cardiologist, and I had very little awareness about veterinary medicine. I, like most physicians, only interacted with veterinarians when my own animals got sick….I had this wonderful opportunity to help out at the Los Angeles Zoo, and through that experience I began seeing, both through the patients I was helping with and listening to the veterinarians on their rounds, that they were dealing with heart failure, and cancer, and behavioral disturbances, and infectious diseases, and really essentially the same diseases that I was taking care of in human patients.

Only a century or two ago, many humans and animals were treated by the same practitioner.

However, animal and human medicine began a decisive split around the turn of the twentieth century. Increasing urbanization meant fewer people relied on animals to make a living. Motorized vehicles began pushing work animals out of our daily life. With them went a primary revenue stream for many veterinarians. And in the United States, federal legislation called the Morrill Land-Grant Acts of the late 1800s relegated veterinary schools to rural communities while academic medical centers rapidly rose to prominence in wealthier cities.

Most physicians would never dream of consulting a veterinarian about human diseases.

Most physicians see animals and their illnesses as somehow “different.” We humans have our diseases. Animals have theirs. 

Well that and the undeniable, and unspoken, medical establishments bias against veterinary medicine. Like all humans, doctors can be snobs. The unwritten hierarchy is based on a combination of factors but it’s pretty safe to bet that a veterinarian is below general practitioner.

“We do not like to consider [animals] our equals,” Charles Darwin once remarked. And yet we are animals. In fact, we share most of our genetic makeup with other creatures. Of course, we do learn from animals. Mice are commonly used to better understand human conditions.

Zoobiquity isn’t about animal testing. It’s about the fact that “animals in jungles, oceans, forests, and our homes sometimes get sick—just as we do. Veterinarians see and treat these illnesses among a wide variety of species. And yet physicians largely ignore this. That’s a major blind spot, because we could improve the health of all species by learning how animals live, die, get sick, and heal in their animal settings.”

One example of where we can learn from is why animals get fat and how they get thin.

Fattening in the animal world has enormous potential lessons for humans—including dieters looking to shed a few pounds and doctors grappling with obesity, one of the most serious and devastating health challenges of our time.

Millions cope with this life-threatening epidemic. Millions of domestic animals that is. These pets are “fatter than ever before, and steadily gaining more weight.” While hard to determine, studies put the number of overweight and obese dogs and cats somewhere between 25 and 40 percent. In case you’re wondering, that’s still, at least for now, well below the proportion of U.S. human adults who are now either overweight or obese, which is closer to 70 percent.

What sets domestic animals apart from their wild cousins? We feed them.

They are mostly or completely dependent on humans for every meal, and we regulate both the quality and the quantity of everything that passes their lips and beaks. Consequently, we can’t really blame them for their weight problems. … And so we’re left with one conclusion: we, the species that both manipulates food to make it more unhealthful and has the intelligence to understand that we shouldn’t eat so much of it, are to blame. We’re responsible not only for our own expanding waistlines but for those of our animal charges as well.

It’s easy and pleasing to assume that animals in their native environments effortlessly stay lean and healthy. That’s not the case.

Abundance plus access—the twin downfalls of many a human dieter—can challenge wild animals, too.

Although we may think of food in the wild as hard to come by, at certain times of the year and under certain conditions, the supply may be unlimited.

So wild animals get fat the same way we humans do: access to abundant food.

Of course, animals also fatten normally—and healthily—in response to seasonal and life cycles. But what’s key is that an animal’s weight can fluctuate depending on the landscape around it.

Learning from animals, call it the zoobiquitous approach, we learn that “weight is not just a static number on a chart. Rather, it’s a dynamic, ever-changing reaction to a huge variety of external and internal processes ranging from the cosmic to the microscopic.”

Richard Jackson says “Obesity is a disease of the environment.” In 2010 he explained what he meant:

One of the problems with the obesity epidemic is we too often blame the victim. And yes, every one of us ought to have more self-control and ought to exert more willpower. But when everyone begins to develop the same set of symptoms, it’s not something in their mind, it’s something in our environment that is changing our health. And what’s changing in our environment is that we have made dangerous food, sugar-laden food, high-fat food, high-salt food … and we’ve made it absolutely the easiest thing to buy, the cheapest thing to buy, and yes, it tastes good, but it’s not what we should be eating.

In a 2009 book, The End of Overeating, David Kessler made a similar point: excess sugar, fat, and salt “hijack our brains and bodies and drive cycles of appetite and desire that make it nearly impossible to resist certain fattening foods.” In a new book I’ve just started reading, Salt Sugar Fat: How the Food Giants Hooked Us, Michael Moss makes the same point. (In case you’re wondering, the calories in calories out argument is bunk.)

One of the lessons we can take away

If you want to lose weight the wild animal way, decrease the abundance of food around yourself and interrupt your access to it. And expend lots of energy in the daily hunt for food. In other words: change your environment.

Nassim Taleb makes a similar point in his book Anti-Fragile:

Perhaps what we mostly need to remove is a few meals at random, or at least avoid steadiness in food consumption. The error of missing nonlinearities is found in two places, in the mixture and the frequency of food intake.

 

The problem with the mixture is as follows. We humans are said to be omnivorous, compared to more specialized mammals, such as cows and elephants and lions. But such ability to be omnivorous had to come in response to more variegated environments with unplanned, haphazard, and, what is key, serial availability of sources—specialization is the response to a very stable habitat free of abrupt changes, redundancy of pathways the response to a more variegated one. Diversification of function had to come in response to variety. And a variety of certain structure.

 

Note a subtly in the way we are built: the cow and the other herbivores are subjected to much less randomness than the lion in their food intake; they eat steadily but need to work extremely hard in order to metabolize all these nutrients, spending several hours a day just eating. … The lion, on the other hand, needs to rely on more luck; it succeeds in a small percentage of the kills, less than 20 percent, but when it eats, it gets in a quick and easy way all these nutrients produced thanks to very hard and boring work by the prey. So take the following principles derived from the random structure of the environment: when we are herbivores, we eat steadily; but when we are predators we eat more randomly. Hence our proteins need to be consumed randomly for statistical reasons.

 

So if you agree that we need “balanced” nutrition of a certain combination, it is wrong to immediately assume that we need such balance at every meal rather than serially so. … There is a big difference between getting them together at every meal … or having them separately, serially.

 

Why? Because deprivation is a stressor—and we know what stressors do when allowed adequate recovery. Convexity effects at work here again: getting three times the daily dose of protein in one day and nothing the next two is certainly not biologically equivalent to “steady” moderate consumption if our metabolic reactions are nonlinear.

… I am convinced that we are antifragile to randomness in food delivery and composition—at least over a certain range or number of days.

We’ve all known that antibiotics are used to stop the spread of certain diseases. But, Zoobiquity, offers another explanation:

Antibiotics don’t kill just the bugs that make animals sick. They also decimate beneficial gut flora. And these drugs are routinely administrated even when infection is not a concern. The reason may surprise you. Simply by giving antibiotics, farmers can fatten their animals using less feed. The scientific jury is still out on exactly why these antibiotics promote fattening, but a plausible hypothesis is that by changing the animals’ gut microflora, antibiotics create an intestine dominated by colonies of microbes that are calorie-extraction experts. This may be why antibiotics act to fatten not just cattle, with their multistomached digestive systems, but also pigs and chicken, whose GI tracts are more similar to ours.

 

This is really a key point: antibiotic use can change the weight of farm animals. It’s possible that something similar occurs in other animals—namely, us. Anything that alters gut flora, including but not limited to antibiotics, has implications not only for body weight but for other elements of our metabolism, such as glucose intolerance, insulin resistance and abnormal cholesterol.

The diet and exercise dogma:Health

Even without an assist from 32-ounce sodas, the yellow-bellied marmots in the Rockies, blue whales off the coast of California and country rats in Maryland have gotten steadily chubbier in recent years. The explanation might lie in the disruption of circadian rhythms. Of the global dynamics controlling our biological clocks — including temperature, eating, sleeping and even socializing — no “zeitgeber” is more influential than light.

The cycle

Modern, affluent humans have created a continuous eating cycle, a kind of “uniseason.” … Sugar is abundant, whether in our processed foods or in beautiful whole fruits that have had their inconvenient seeds bread out of them and that “unzip” from easy-to-peel skins and pop open into ready to eat segments. Protein and fat are everywhere available—in eternal harvest the prey never grows up and learns to run away or fight us off. Our food is stripped of microbes, and we remove more while scrubbing off dirt and pesticides. Because we control it, the temperature is always a perfect 74 degrees. Because we’re in charge, we can safely dine at tables aglow in light long after the sun goes down. All year round, our days are lovely and long; our nights are short.

 

As animals, we find this single season an extremely comfortable place to be. But unless we want to remain in a state of continual fattening, with accompanying metabolic diseases, we will have to pry ourselves out of this delicious ease.

Anglerfish entered the midnight zone 55 million years ago and thrived by becoming sexual parasites

Anglerfish first colonized the ocean's midnight zone 55 million years ago, during a period of extreme global warming, a new study finds. The bizarre fish adapted to thrive in the deep sea by becoming sexual parasites, the researchers said.

These fish, in the order Lophiiformes, are among the most diverse vertebrate groups in the deep sea, having assumed a myriad of forms. Among their most recognizable features are their bioluminescent lures. The light from these dangling organs entices prey, drawing them within inches of a nightmarish array of needle-like teeth.

Many anglerfish species patrol the benthic, or seafloor, zone, ranging from the near shore to depths of thousands of feet. They walk along the bottom using modified fins that resemble legs. But others live in deep open water of the bathypelagic, or midnight zone, 3,000 to 13,000 feet (900 to 4,000 meters) below the surface.

A new study, published Jan. 15 on the preprint server BioRxiv, suggests anglerfish of the group Ceratioidea colonized the midnight zone during the Paleocene-Eocene Thermal Maximum, which occurred 55 million years ago and lasted for around 200,000 years. 

This period may have been initiated by volcanic events that released methane into the atmosphere. The temperatures were so extreme, polar seas reached temperatures of up to 73 degrees Fahrenheit (23 degrees Celsius), while tropical sea surface temperatures may have gotten as warm as 97 F (36 C).

The event wiped out numerous deep-sea organisms and likely opened up new ecological niches. And ceratioid anglerfish, it appears, were primed to take advantage of them thanks to a set of unique adaptations, the researchers revealed. 

Most ceratioid anglerfish diverged from their more-coastal cousins 50 million to 30 million years ago, aligning with these climatic shifts.

A female anglerfish with male sexual parasites attached to her body. (Image credit: Neil Bromhall/Shutterstock)© Provided by Live Science

"What we found is that they went into the deep ocean, much like whales going back into the ocean from walking ancestors," lead author Chase Brownstein, a first year graduate student at Yale, told Live Science. "Anglerfish just did it in reverse. They were walking on the ocean floor and they went back up into the water column."E

Living in the midnight zone means having no real home — there are no reefs, caves, seaweed or other substrate to grasp onto. This lifestyle is not conducive to finding a mate, but the researchers suggest anglerfish adopted new breeding strategies to thrive in this featureless landscape.

Firstly, they seem to locate each other by scent.

"The males have these giant nostrils. It's very sci-fi. We think they're picking up on pheromones," Brownstein said.

When an anglerfish does encounter a potential partner in the darkness, it doesn't want to let go. Sometimes, males temporarily attach to females, which are significantly larger. "The dimorphism is ridiculous," Brownstein said. "Males are 1/100 the size of females in some cases."

And sometimes the males fuse to their partners permanently — that is, the males are sexual parasites, merging with females' bodies. In some species, only one male fuses with the female. In others, multiple males may attach to the female. 

This unique reproductive strategy is the result of immune system deficiencies. Typically, the adaptive immune system would recognize and destroy foreign cells. But the loss of these immune functions — the generation of certain antibodies for example —enables the female to accept the male as part of her own body, feeding him with her blood supply. He in turn serves as a permanent sperm bank. 

The researchers believe that the degeneration of the immune system and its facilitation of sexual parasitism were advantageous during this period of radical ecosystem upheaval, allowing anglerfish to head off into the featureless depths and diversify into the array of Lovecraftian creatures that stalk the midnight zone today.

"I think this might be an example of what's called exaptation, which is the idea that traits that don't have a clear positive adaptive role are later expressed in a new context and do provide an adaptive role," Brownstein said.

Reference: Live Science: