Cold weather often brings with it hot takes on so-called man flu. That’s the phenomenon in which the flu hits men harder than women — or, depending on who you ask, when men exaggerate regular cold symptoms into flu symptoms. In time for the 2017–2018 flu season, one researcher has examined the scientific evidence for and against man flu.

“The concept of man flu, as commonly defined, is potentially unjust,” Kyle Sue, a clinician at Memorial University of Newfoundland in St. John’s, Canada, writes December 11 in BMJ. Motivated by his own memorable bout of flu, he says, Sue began looking into man flu research and summarizes the work in a review article that’s part of BMJ’s Christmas issue, which traditionally features humorous takes on legitimate research.
There might be a reason men come across as wimps. In the United States, more men than women died from flu-related causes from 2007 to 2010 across several age groups, researchers reported in the American Journal of Epidemiology in 2013. An analysis of data on the 2004 to 2010 flu seasons in Hong Kong found that in children and adults, males were more likely to be hospitalized for the flu than females.

Sue isn’t the first to make a case for man flu. A prevailing explanation for men’s susceptibility says that women have higher levels of the hormone estradiol, which can boost the immune system, while men have higher levels of testosterone, which can sometimes suppress the immune system. However, these hormones interact with the immune system in other ways as well.

“There is some evidence that men make weaker immune responses to some viruses than women, but how this happens and whether it is seen across all viruses is still unclear to me,” notes John Upham, professor of respiratory medicine at Queensland University in Australia.

Sue’s review also cites evidence that women respond better to some flu shots than men do. Sex differences in immune response could have real consequences when it comes to vaccine choice, Upham says.
It’s also unclear what the evolutionary drivers for immune differences between the sexes might be. And studies of how the male and female immune systems respond differently all come with caveats, Sue notes: Such studies are often in mice rather than humans, have limited data or don’t account for health differences such as smoking habits and tendency to go to the doctor. Upham adds that studying differences in flu cases among men in Western versus non-Western societies could reveal the degree to which learned behavior plays a role in “man flu.”

As much as he’d like to help out his half of the species, Sue says, “we cannot yet conclude that this phenomenon is real, but the current evidence is suggestive that it may be.” Not surprising, his review has met just as much skepticism as previous man flu treatises.

Regardless of the possibility that men may be immunologically weaker than women, Sue says, both flu-stricken men and women alike “could benefit from resting in a safe, comfortable place with a recliner and TV.”

Rising carbon dioxide levels could leave some tiny lake dwellers defenseless. Like the oceans, some lakes are experiencing increasing levels of the greenhouse gas, a new study shows. And too much CO2 in the water may leave water fleas, an important part of many lake food webs, too sleepy to fend off predators.

Detailed observations of lake chemistry over long periods of time are rare. But researchers found data from 1981 to 2015 on four reservoirs in Germany, allowing the scientists to calculate how much CO2 levels had risen and how much pH levels, measuring acidity in the water, had dropped, the scientists report online January 11 in Current Biology.

Rising CO2 in Earth’s atmosphere has also increased levels of the gas dissolved in the oceans, making them more acidic (SN: 5/27/17, p. 11). Studies show that ocean acidification alters the behaviors of marine species (SN Online: 2/2/17). It’s less clear how rising atmospheric CO2 levels are affecting freshwater bodies, or how their denizens are coping with change, says aquatic ecologist Linda Weiss of Ruhr University Bochum in Germany.
Comparing the data from the four reservoirs showed that, in those 35 years, the average CO2 level across all lakes rose by about 560 microatmospheres, a unit of pressure. Two of the water bodies experienced a roughly fourfold increase in CO2 levels. For pH, the overall average value dropped from 8.13 to 7.82.

In the lab, the team examined the effect that high CO2 had on the behavior of two species of water fleas, or pinhead-sized lake dwellers also known as Daphnia. The miniature crustaceans are at the bottom of many freshwater food webs. When predators such as the larvae of phantom midges feed on Daphnia, the predators release a chemical signal that cues various species of water fleas to arm themselves with an array of defenses. Some raise forbidding neck spikes; others grow giant “helmets” that make the critters tougher to swallow.
But the water fleas’ sense of danger seemed to be dulled in waters with high CO2 levels. The team tested the critters in waters containing both chemical predator cues and CO2 at partial pressures of 2,000, 11,000 and 16,000 microatmospheres. Although 2,000 microatmospheres is considered high, it is now common enough in lakes that the team used it as the control case. Both species were less defensive at 11,000 and 16,000 microatmospheres (considered worst-case scenario values for many lakes) — displaying fewer neck spikes or developing smaller crests.

Further tests revealed that the elevated CO2 was responsible, rather than the reduced pH. Although it’s unclear exactly how the elevated carbon dioxide leads Daphnia to lower its defenses, the researchers suggest the CO2 acts as a narcotic and blunts the senses.

The variability between lakes in terms of setting and chemistry makes it difficult to draw firm conclusions from the findings, Weiss says. Many lakes are warming (SN: 5/13/17, p. 18). And many are already saturated in carbon dioxide and expelling it into the atmosphere. Others are absorbing it and becoming more acidic.

It is also unclear how other freshwater species, including predators, might be affected at different CO2 levels and in different environments, says Caleb Hasler, an organismal biologist at the University of Winnipeg in Canada, who was not involved in the study. “There’s been a bit of work done on phytoplankton, some on zooplankton, freshwater fishes and mussels. If anything, the effect seems to be highly variable.”

But studies such as this that show long-term trends in CO2 levels are an important part of solving the puzzle, Hasler says. And “showing that there is an impact on an important species is pretty significant.”

Out of the hundreds of species of carnivorous plants found across the planet, none attract quite as much fascination as the Venus flytrap. The plants are native to just a small section of North Carolina and South Carolina, but these tiny plants can now be found around the world. They’re a favorite among gardeners, who grow them in homes and greenhouses.

Scientists, too, have long been intrigued by the plants and have extensively studied the famous trap. But far less is known about the flower that blooms on a stalk 15 to 35 centimeters above — including what pollinates that flower.
“The rest of the plant is so incredibly cool that most folks don’t get past looking at the active trap leaves,” says Clyde Sorenson, an entomologist at North Carolina State University in Raleigh. Plus, notes Sorenson’s NCSU colleague Elsa Youngsteadt, an insect ecologist, because flytraps are native to just a small part of North and South Carolina, field studies can be difficult. And most people who raise flytraps cut off the flowers so the plant can put more energy into making traps.

Sorenson and Youngsteadt realized that the mystery of flytrap pollination was sitting almost literally in their backyard. So they and their colleagues set out to solve it. They collected flytrap flower visitors and prey from three sites in Pender County, North Carolina, on four days in May and June 2016, being careful not to damage the plants.

“This is one of the prettiest places where you could work,” Youngsteadt says. Venus flytraps are habitat specialists, found only in certain spots of longleaf pine savannas in the Carolinas. “They need plenty of sunlight but like their feet to be wet,” says Sorenson. In May and June, the spots of savanna where the flytraps grow are “just delightful,” he says. And other carnivorous plants can be found there, too, including pitcher plants and sundews.
The researchers brought their finds back to the lab for identification. They also cataloged what kind of pollen was on flower visitors, and how much.
Nearly 100 species of arthropods visited the flowers, the team reports February 5 in American Naturalist. “The diversity of visitors on those flowers was surprising,” says Youngsteadt. However, only three species — a sweat bee and two beetles — appeared to be the most important, as they were either the most frequent visitors or carriers of the most pollen.
The study also found little overlap between pollinators and prey. Only 13 species were found both in a trap and on a flower, and of the nine potential pollinators in that group, none were found in high numbers.

For a carnivorous plant, “you don’t want to eat your pollinators,” Sorenson says. Flytraps appear to be doing a good job at that.

There are three ways that a plant can keep those groups separate, the researchers note. Flowers and traps could exist at different times of the year. However, that’s not the case with Venus flytraps. The plants produce the two structures at separate times, but traps stick around and are active during plant flowering.

Another possibility is the spatial separation of the two structures. Pollinators tend to be fliers while prey were more often crawling arthropods, such as spiders and ants. This matches up with the high flowers and low traps. But the researchers would like to do some experiments that manipulate the heights of the structures to see just how much that separation matters, Youngsteadt says.

The third option is that different scents or colors produced by flowers and traps might lure in different species to each structure. That’s another area for future study, Youngsteadt says. While attraction to scent and color are well documented for traps, little is now known about those factors for the flowers.

Venus flytraps are considered vulnerable to extinction, threatened by humans, Sorenson notes. The plant’s habitat is being destroyed as the population of the Carolinas grows. What is left of the habitat is being degraded as fires are suppressed (fires help clear vegetation and keep sunlight shining on the flytraps). And people steal flytraps from the wild by the thousands.

While research into their pollinators won’t help with any of those threats, it could aid in future conservation efforts. “Anything we can do to better understand how this plant reproduces will be of use down the road,” Sorenson says.

But what really excites the scientists is that they discovered something new so close to home. “One of the most thrilling parts of all this,” Sorenson says, “is that this plant has been known to science for [so long], everyone knows it, but there’s still a whole lot of things to discover.”

Editor’s Note: This story was updated February 9 to note President Trump’s fiscal year 2019 budget proposal.

A two-year spending package, passed by Congress in the wee hours of February 9 and signed into law by President Trump hours later, could add to the coffers of U.S. science agencies.

The bipartisan deal raises the caps on defense and nondefense discretionary spending by nearly $300 billion overall. Nondefense discretionary spending gets a $63 billion boost in fiscal year 2018, and another $68 billion in FY 2019 (the spending year that starts October 1, 2018). Here’s why that could be good for science: Almost all research agencies, including NASA, EPA, the National Science Foundation and the National Institutes of Health, fall under this nondefense category. (Defense agencies also do a chunk of scientific research.) But there is a big but. It’s still unclear how any funds will be divvied up among individual agencies and programs. (Early word is that NIH is in line for a $2 billion increase over the two years.)
Still, the real details of who gets what in the 2018 budget — including what science will get federal funding support — will come as Congress works on an omnibus appropriations bill, expected in late March.
Trump’s FY 2019 budget proposal, released February 12, includes a last-minute addendum that would keep science spending roughly at 2017 levels for some major research agencies, including NIH, NSF and the Department of Energy Office of Science. But a number of federal research programs and projects remain in Trump’s cross hairs, including five of NASA’s Earth science missions and various research, including on climate or environmental science, at the EPA, the National Oceanic and Atmospheric Administration and the U.S. Geological Survey. Whether Congress will go along with Trump’s request for the 2019 budget remains to be seen.

Matt Hourihan, director of the R&D Budget and Policy program at the American Association for the Advancement of Science in Washington, D.C., spoke with Science News February 9 about the prospects for funding for science research. His answers were edited for clarity.

SN: What does the spending deal mean for science research and technology funding?

M.H.: Generally, research and development funding tends to track the discretionary budget pretty closely, though individual agencies may fare a little better or worse in any given year. But most likely we’re looking at a larger increase this year, and then a far more moderate increase next year. Within that context, agencies will fare better or worse based on their current popularity.

SN: Are there any obvious winners or losers?

M.H.: We won’t really know that until the omnibus deal is released. All we have is an overall framework, but spending levels for individual agencies and programs will need to be negotiated and the details released. I would certainly expect more winners than losers, given how large a spending increase we’re talking about. The deal apparently includes some extra funding for NIH, though again we’ll see how the details look.

SN: Could the extra money still be cut?

M.H.: Whatever Congress does, they can, of course, undo. But if they lower the cap next year after raising it, it would be the first time. The downside is, this does add quite a bit to the deficit. With this deal plus the recent tax reform, we’re looking at a potential return to trillion-dollar deficits next year. When deficits get bigger, Congress gets more interested in restraining spending, and trillion-dollar deficits are what got us here in the first place. It’s a catch-22.

SN: How will Trump’s FY 2019 budget proposal impact how the money is divvied up?

M.H.: Last year’s budget proposed big cuts to nondefense spending, and now Congress has gone in the complete opposite direction. We’ll see what the administration does … but if they go for a repeat performance, we could be looking at a pretty irrelevant [Trump] budget.

No wounded left behind — not quite. Ants that have evolved battlefield medevac carry only the moderately wounded home to the nest. There, those lucky injured fighters get fast and effective wound care.

Insect colonies seething with workers may seem unlikely to stage elaborate rescues of individual fighters. Yet for Matabele ants (Megaponera analis) in sub-Saharan Africa — with a mere 1,000 to 2,000 nest mates — treating the wounded can be worth it, says behavioral ecologist Erik Frank at the University of Lausanne in Switzerland.
Tales of self-medication pop up across the animal kingdom. For Matabele ants, however, nest cameras plus survival tests show insects treating other adults and improving their chances of survival, he and colleagues report February 14 in Proceedings of the Royal Society B. For treatment boosting others’ survival, Frank says, the closest documented example is humans.

In Ivory Coast, Frank studied Matabele ant colonies that staged three to five termite hunts a day. He and colleagues at the University of Würzburg in Germany published research last year showing that members of a hunting party carry injured comrades home.
Frank took a closer look at rescues after he accidentally drove over a Matabele ant column crossing a road. Survivors “were only interested in picking up the ants that were lightly injured, and leaving behind the heavily injured,” he says.
When Frank later set injured ants in front of columns trooping home from raids, injured ants minus two legs typically got picked up. Only once did an ant with five missing legs get a lift.

Ants that have lost two legs still have value to a colony, especially in a species where only about 13 new adults a day emerge from pupae. Four-legged ants regain almost the same speed that ants have on six legs, he says. In a typical hunting party, about a third of the ants have survived some injury, but most ants have at least four legs left.

How the ants triage a battlefield evacuation is shaped by the injured ants’ behavior, Frank says. Ants with only moderate injuries, such as two lost legs, emit “help me” pheromones. These ants tuck in their remaining legs and generally cooperate with the rescuers. Not so with ants more seriously hurt, who may not even give off pheromones. Rescuers still stop to investigate. But the seriously injured ants often flail around instead of cooperating, and the rescuers give up.

Frank also has seen ants act more severely injured than they truly are. If the returning fighters bypass them, “they will immediately stand up and run as fast as they can behind the others,” he says. “In humans, it’s a very selfish behavior.” For ants, predators lurk, and the colony benefits by finding the injured first.
For injured raiders that do get home, another ant — usually not the carrier — steps in to treat the wound by repeatedly moving her mouthparts over it. When Frank isolated the ants to prevent this wound licking, about 80 percent of injured ants died. When he allowed ants an hour of treatment before isolating them, only 10 percent of them died.

Based on Frank’s observations, others who study ants are now wondering if they also have seen such rescue tactics. Andy Suarez of the University of Illinois at Urbana-Champaign wants another look at big Dinoponera australis that he’s frequently seen prowling for prey despite missing a limb. And Bert Hölldobler wonders whether weaver ants he has seen retrieving injured nest mates after battle were rescuing them. The usual interpretation has been cannibalism, says Hölldobler, at Arizona State University in Tempe.

Frank, however, used bright acrylic spots to track the fate of rescued Matabele ants. They weren’t for lunch.