Enlarge / Eyes painted on cattle rumps trick lions into thinking they have lost the element of surprise, a new study suggests. (credit: Ben Yexley )

Cattle herds in the Okavango delta region in Botswana are plagued by attacks by lions and other predators, prompting farmers to retaliate by killing the predators. An alternative nonlethal technique involves painting eyes on the butts of cattle to trick ambush predators like lions into thinking they've been spotted by their intended prey. It's called the " Eye-Cow Project ," and a recent paper published in the journal Communications Biology provides some solid empirical evidence for the practice. There are now practical guides for using the "eye-cow" technique available in both English and Setswana, so farmers can try it out for themselves.

Neil Jordan, a conservation biologist at the University of New South Wales in Australia, came up with the idea several years ago while he was doing field work in Botswana. Local farmers killed a pair of lionesses in retaliation for preying on their herds of cattle, and Jordan wanted to come up with a non-lethal alternative. The African lion population has dropped significantly from more than 100,000 in the 1990s to somewhere between 23,000 and 39,000 in 2016—much of it due to retaliation killings.

Jordan knew that butterfly wings sporting eye-like patterns are known to ward off preying birds, and are also found in certain fish, mollusks, amphibians and birds, although such patterns had not been observed in mammals. He also discovered that woodcutters in Indian forests have been known to wear masks on the backs of their heads to discourage any tigers hunting for prey. He had observed a lion stalking an impala, and noticed the predator gave up the chase when the prey spotted it. Lions are ambush hunters, Jordan reasoned, and decided to test his "detection hypothesis" that painting eyes on the butts of cows would discourage predatory behavior from the local lion population.

Enlarge (credit: NOAA )

The year 2020 may be one for the record books in terms of apocalyptic tidings. In addition to the usual background of fires , floods , and earthquakes , the plague is still around . And you might have heard something about a pandemic . But what really nails down the apocalyptic vibe is the fact that the year's seen swarms of locusts causing the sorts of problems they're famous for.

In a tiny bit of good news, the same sort of research that may bail us out with therapies and a vaccine for SARS-CoV-2 could potentially help us out against future locust swarms. That's because a team of biologists based in China has now identified the chemical that calls locusts to swarm and shown that genetic engineering can eliminate the response.

A lot of evidence

There's nothing especially exciting about any single aspect of the research here. Instead, the researchers simply put together techniques from a variety of specializations and then applied them to the topic of locust swarms. Locusts are normally solitary animals, but they become immensely destructive when conditions induce them to form massive swarms that are big enough to be picked up by radar . In addition to the altered behavior, swarming locusts actually look physically different, indicating that the decision to swarm involves widespread changes to a locust's biology.

Enlarge / Commuters wear face masks as they travel on the London Underground on June 12, 2020 as lockdown measures are eased during the novel coronavirus COVID-19 pandemic. (credit: TOLGA AKMEN/AFP)

Advice on whether or not to use face masks to limit the spread of the pandemic has varied from country to country, even differing by location within countries. These policies have had to balance whether there were sufficient supplies for medical personnel to divert some to the general public. And the whole issue was decided without a clear idea of whether face masks were actually effective against SARS-CoV-2.

But there has been reason to think masks would at least be somewhat affective, based on studies of the spread of droplets of material we expel while coughing or sneezing. And a recent analysis suggested a large group of individual studies collectively pointed to their effectiveness. But that analysis left a large degree of uncertainty about how effective they'd be at the population level and how face mask use would interact with other policy decisions.

The situation left us needing population-level modeling, which a group of UK scientists has now provided. The group's model indicates that face masks don't have to be especially effective to slow the spread of SARS-CoV-2 and can even bring benefits if they make people more vulnerable to infection. But to really control the pandemic, they will have to be combined with a lockdown if we want to see the total infected population shrink.

Enlarge / After her research career effectively ended, Dr. Judy Mikovits has re-emerged as an anti-vaccine activist. (credit: YouTube)

Back in 2011, we covered the strange story of biochemist Judy Mikovits, who co-authored a controversial (and subsequently retracted) paper in the journal Science and eventually lost her prestigious position with a research institution. Now Mikovits is back in the news, having spent the ensuing years reinventing herself as a staunch anti-vaccine crusader.

The COVID-19 pandemic has given her a new conspiracy to tout, this time targeting Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at NIH, who has become a prominent public spokesperson during the outbreak. Two interviews in particular have been spreading rapidly on social media, prompting YouTube and Facebook to remove both video clips for spreading medical misinformation during a global pandemic—a violation of their current policies

In 2007, Mikovits met Robert Silverman at a conference. Silverman had co-discovered a retrovirus known as XMRV, closely related to a known virus from mice. He told her he had found XMRV sequences in specimens from prostate cancer patients, although other labs, using different sets of patients, could find no evidence of a viral infection. Nonetheless, this prompted Mikovits to use the same tools to look for XMRV in samples from patients suffering from chronic fatigue syndrome (CFS)—a disorder some had claimed was purely psychosomatic.

Enlarge (credit: Orange County NC )

Plastics have a lot of properties that have made them fixtures of modern societies. They can be molded into any shape we'd like, they're tough yet flexible, and they come in enough variations that we can tune the chemistry to suit different needs. The problem is that they're tough enough that they don't break down on their own, and incinerating them is relatively inefficient. As a result, they've collected in our environment as both bulk plastics and the seemingly omnipresent microplastic waste.

For natural materials, breaking down isn't an issue, as microbes have evolved ways of digesting them to obtain energy or useful chemicals. But many plastics have only been around for decades, and we're just now seeing organisms that have evolved enzymes to digest them. Figuring they could do one better, researchers in France have engineered an enzyme that can efficiently break down one of the most common forms of plastic. The end result of this reaction is a raw material that can be reused directly to make new plastic bottles.

An unwanted PET

The plastic in question is polyethylene terephthalate, or PET. PET has a variety of uses, including as thin films with very high tensile strength (marketed as mylar). But its most notable use is in plastic drink bottles, which are a major component of environmental plastic waste. First developed in the 1940s, the first living organism that can break down and use the carbon in PET was described in 2016 —found in sediment near a plastic recycling facility, naturally.

Enlarge / A vampire bat in flight with spread wings. The creatures build strong social bonds through grooming, sharing blood. (credit: Samuel Betkowski/Getty Images)

Vampire bats can starve to death if they don't feed for a mere three days, so strong social ties can be key to survival. For instance, a bat will sometimes share food with a hungry member of the same roost, regurgitating any blood it has consumed into the mouth of the hungry bat—a bit like a bloody French kiss. That's a true "friend." Evolutionary biologists have dubbed this behavior "reciprocal altruism." But vampire bats can also form bonds with strange bats from outside the roost, building up trust with mutual grooming first before moving on to food sharing, according to a new paper in Current Biology.

What's being tested here is a game theory model first proposed in 1998 colloquially known as "raise the stakes." It's similar to the famous prisoner's dilemma , in which two criminal suspects are arrested and separately offered a deal. If one of them confesses and the other doesn't, the defector will go free and the other suspect will get 20 years in jail. If both suspects confess, they will each get ten years in jail. The correct strategy, therefore, is to always confess, since one should assume the other party will act solely in his or her self-interest. Both players will reap the most benefit by cooperating with each other.

But cooperative behavior isn't always quite so simple as a binary choice between cooperating or defecting; it's more like a continuously variably investment. The "raise the stakes" model of relationships holds that two strangers can make low-risk, incremental investments to see if there is potential for further cooperation. If the other party reciprocates in kind, it builds trust and a relationship can form. If not, no relationship will develop, and nobody has spent too much time and energy on a worthless (from a survival standpoint) connection.

Enlarge / Phages on the surface of a bacterial cell. (credit: Dr. Graham Beards )

In many cases, viruses manage to spread so readily because they're so compact, allowing hundreds of thousands of viral particles to explode from a single sneeze. That compact size comes in part from their limited needs. Since viruses use parts of their host cells for much of what they need to do, even the more complicated viruses tend to only need a few dozen specialized genes to do things like evade the immune system or remain dormant in cells. In fact, complexity would seem to go against one of virus' evolutionary advantages: the ability to make lots of copies of itself very quickly.

So it was a bit of a surprise to find that there are giant viruses that carry far more genetic material than they seemingly need. All cells carry the machinery needed to make proteins so, at most, viruses typically carry just a few genes that direct the machinery to focus on the virus' needs. But the giant viruses seemed to carry replacements for much of the basic machinery itself. Those viruses were attacking complicated cells, with a lot of internal structures and many complex biological processes going on in different locations. Maybe carrying all those seemingly superfluous parts was advantageous in that context.

Or possibly not. In a study released today, researchers describe a large collection of giant viruses that target bacteria. While smaller than some of the largest eukaryotic viruses, they're not that much smaller. And given that they infect bacteria, the genomes of the newly described viruses may be a substantial fraction of the size of their host's genome.