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When a male Australian peacock spider wags its bottom at you, it's impossible to look away. In the throes of courtship, ...
08/02/2023

When a male Australian peacock spider wags its bottom at you, it's impossible to look away. In the throes of courtship, the spider's glittering badonkadonk shimmers with all the colors of the rainbow, diffracting intense iridescent light like a living Lisa Frank sticker.

Scientists calls the spectacle "nature's smallest rainbow" — in fact, peacock spider bodies measure at most 5 millimeters (0.2 inches) long, according to a new paper(opens in new tab) published online in the journal Nature Communications. The researchers also noted that the flashy display is the only known example in nature of males deploying all the colors of the rainbow to entice females during courtship. [In Photos: Meet 7 New Species of Peacock Spider]

The team of researchers from the United States, Belgium, the Netherlands and Australia think they know how two species of miniature peacock spiders (Maratus robinsoni and Maratus chrysomelas) get the dazzling job done. The trick, the researchers say, is in their scales.

"M. robinsoni and M. chrysomelas have two types of visually distinct abdominal scales: rainbow-iridescent scales and velvet black scales," the researchers wrote in their new paper. "These scales show strikingly different morphologies: The black scales are brush-like and randomly oriented, while the rainbow-iridescent scales are more orderly aligned, cling to the cuticle surface and have bulky 3D shapes."

A zoom-in view of the scaly abdomen of the Peacock spider Maratus robinsoni.

A zoom-in view of the scaly abdomen of the Peacock spider Maratus robinsoni. (Image credit: Dr. Jürgen Otto)
The researchers took a closer look at these bulky, iridescent scales using a variety of imaging techniques,to better understand the surfaces' unique rainbow-scattering properties. The team discovered that each iridescent scale contains a series of three-dimensional, parallel grates used to split different wavelengths of light at different angles.

"The unique grating configuration of each M. robinsoni scale disperses the visible spectrum over a small angle, such that at short distances, the entire visible spectrum is resolved, and that a static microscopic rainbow pattern distinctly emerges," the authors wrote.

These insights allowed the team to successfully fabricate their own miniature rainbow-scattering surfaces based on the same pattern seen on the spiders' scales. According to a statement from the University of Akron (which participated in the study), this spider-inspired knowledge could help push the boundaries of optics and color technology, particularly where fine-scale color resolution is required in small packages, as in instruments on space missions or wearable chemical-detection systems. Still, more work is required to match the spiders' exact capabilities.

"As an engineer, what I found fascinating about these spider structural colors is how these long-evolved, complex structures can still outperform human engineering," Radwanul Hasan Siddique, a postdoctoral scholar at Caltech and a co-author of the new research, said in the statement. "I wonder how the spiders assemble these fancy structural patterns in the first place."

Legendary musician Fats Domino died this week at age 89, and officials reported his death was due to "natural causes." B...
08/02/2023

Legendary musician Fats Domino died this week at age 89, and officials reported his death was due to "natural causes." But what exactly does it mean to die from natural causes?

In simple terms, natural causes refer to internal factors — like a medical condition or a disease — as opposed to external factors, like trauma from an accident. In other words, natural causes could be anything from cancer to heart disease to diabetes.

"It just means there was nothing non-natural that happened in [the patient's] cause of death," said Dr. Patricia Allenby, director of autopsy services at the Ohio State University Wexner Medical Center. [Top 10 Leading Causes of Death]

On a death certificate, natural causes actually refers to the "manner of death" rather than the specific cause. Authorities indicate whether the manner of death was natural, accidental, or due to su***de or homicide, Allenby said.

Another section of the death certificate includes more specific information about the cause of death, including the "immediate cause" that occurred at the time of death and the "underlying causes" that led up to the death, Allenby said. For example, a person's immediate cause of death might be an "acute heart attack," in which blood flow to the heart is suddenly blocked, while the underlying cause of death might be "atherosclerotic coronary artery disease," a condition in which plaque made of fat, cholesterol and other substances builds up in the body's arteries. In this scenario, the manner of death would also be natural.

Sometimes, determining the manner of death is not so straightforward. For example, Allenby recalled a case in which a person had a stroke, and underwent whirlpool therapy for symptoms after the stroke. But the pool was too hot, and the patient sustained burns, Allenby said. The patient later died from infection of the burns. In this case, even though the stroke (a natural event) led to the whirlpool therapy, and the person died from an infection, the manner of death is still non-natural, because an accident contributed to the death, Allenby said.

Whether a person's death is natural or non-natural also determines who signs the death certificate, Allenby said. If a death is determined to be natural, the certificate can be signed by an attending physician, and the autopsy can be performed at a hospital; but if the death is determined to be non-natural (external), then the case is turned over to the coroner or medical examiner for investigation, Allenby said.

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