Three strange stories of biology

1.    Aphids are weird, and Nature reports that they show the first evidence for photosynthesis in insects:

The biology of aphids is bizarre: they can be born pregnant and males sometimes lack mouths, causing them to die not long after mating. In an addition to their list of anomalies, work published this week indicates that they may also capture sunlight and use the energy for metabolic purposes.

Aphids are unique among animals in their ability to synthesize pigments called carotenoids. Many creatures rely on these pigments for a variety of functions, such as maintaining a healthy immune system and making certain vitamins, but all other animals must obtain them through their diet. Entomologist Alain Robichon at the Sophia Agrobiotech Institute in Sophia Antipolis, France, and his colleagues suggest that, in aphids, these pigments can absorb energy from the Sun and transfer it to the cellular machinery involved in energy production¹.

This reminds me of how the advanced modified bodies given to the characters in John Scalzi's Old Man's War had (I think) greenish tinged skin because they could photosynthesise.  I wonder if aphid genes could be the way to do that.  (I didn't care for the book much, by the way.)

2.   It still pays to look carefully, it seems.  Isn't it odd that this is only being found now?:

A previously unrecognized system that drains waste from the brain at a rapid clip has been discovered by neuroscientists at the University of Rochester Medical Center....

The highly organized system acts like a series of pipes that piggyback on the brain's blood vessels, sort of a shadow plumbing system that seems to serve much the same function in the brain as the lymph system does in the rest of the body – to drain away waste products.

 Nedergaard's team has dubbed the new system "the glymphatic system," since it acts much like the lymphatic system but is managed by brain cells known as glial cells. The team made the findings in mice, whose brains are remarkably similar to the human brain. Scientists have known that cerebrospinal fluid or CSF plays an important role cleansing brain tissue, carrying away waste products and carrying nutrients to brain tissue through a process known as diffusion.

The newly discovered system circulates CSF to every corner of the brain much more efficiently, through what scientists call bulk flow or convection. "It's as if the brain has two garbage haulers – a slow one that we've known about, and a fast one that we've just met," said Nedergaard. "Given the high rate of metabolism in the brain, and its exquisite sensitivity, it's not surprising that its mechanisms to rid itself of waste are more specialized and extensive than previously realized."

 3.    Israel seems to have a particularly clear case of decreasing sperm quality, and no one is sure why:

Over the last 10 to 15 years, the concentration of sperm samples collected by the bank dropped 37% from 106 million cells per milliliter to 67 million, according to Dr. Ronit Haimov-Kochman, a leading Israeli infertility researcher at the Hadassah Hebrew University Medical Center.

Though declining sperm quality is an international phenomenon, the change in Israel is occurring at nearly twice the pace as other developed countries, Haimov-Kochman said. If current trends continue, she said, by 2030 the concentration of sperm from Israeli donors will drop below 20 million cells per milliliter, which many international health experts define as abnormal.

One of the more surprising possible reasons is from their dairy practices:

"People in Israel are getting quite a load of estrogen," said Laurence Shore, a retired hormone and toxicology researcher at the Kimron Veterinary Institute near Tel Aviv. "I don't think it's a good idea to expose children to such high levels of estrogen."

He said that no studies so far have determined that estrogen levels in Israel are harming humans, adding that exposure may be too low for that. But he said it might be a factor in the sperm decline.  His research has found Israeli milk and associated products such as butter and cheese can contain 10 times as much estrogen as products from other countries because of Israel's aggressive milk-production practices.

Israel is a world leader in producing milk, pumping twice as much from its cows as other parts of the world, he said. That's partly because cows here are milked up to their eighth month of pregnancy, when natural estrogen levels in the milk soar, according to Shore. In nature, he said, cows usually stop giving milk to their own young when they are three months pregnant with a new calf.

Even though many other nations have adopted similar milking practices, Shore said, Israel is one of the first and most aggressive, so it could be seeing the effect sooner.