The new VISTA telescope takes a look at NGC 253. Click for larger. Credit: ESO

Looks like the new Visible and Infrared Survey Telescope (VISTA) at the ESO facility in Chile is doing quite nicely as this image of NGC 253, a member of the  Sculptor Galaxy group shows.  Seems like there’s been a few breakthroughs in imaging technology lately.

They didn’t mention any globular clusters around the halo, I wonder if they are any there and what the absence might say about the age of this beautify spiral galaxy.

Here’s the ESO press release:

The Sculptor Galaxy (NGC 253) lies in the constellation of the same name and is one of the brightest galaxies in the sky. It is prominent enough to be seen with good binoculars and was discovered by Caroline Herschel from England in 1783. NGC 253 is a spiral galaxy that lies about 13 million light-years away. It is the brightest member of a small collection of galaxies called the Sculptor Group, one of the closest such groupings to our own Local Group of galaxies. Part of its visual prominence comes from its status as a starburst galaxy, one in the throes of rapid star formation. NGC 253 is also very dusty, which obscures the view of many parts of the galaxy (eso0902). Seen from Earth, the galaxy is almost edge on, with the spiral arms clearly visible in the outer parts, along with a bright core at its centre.

VISTA, the Visible and Infrared Survey Telescope for Astronomy, the latest addition to ESO’s Paranal Observatory in the Chilean Atacama Desert, is the world’s largest survey telescope. After being handed over to ESO at the end of 2009 (eso0949) the telescope was used for two detailed studies of small sections of the sky before it embarked on the much larger surveys that are now in progress. One of these “mini surveys” was a detailed study of NGC 253 and its environment.

As VISTA works at infrared wavelengths it can see right through most of the dust that is such a prominent feature of the Sculptor Galaxy when viewed in visible light. Huge numbers of cooler stars that are barely detectable with visible-light telescopes are now also seen. The VISTA view reveals most of what was hidden by the thick dust clouds in the central part of the disc and allows a clear view of a prominent bar of stars across the nuclear region — a feature that is not seen in visible light pictures. The majestic spiral arms now spread over the whole disc of the galaxy.

The spectacular viewing conditions VISTA shares with ESO’s Very Large Telescope (VLT), located on the next mountain peak, also allow VISTA images to be exceptionally sharp for a ground-based telescope.

With this powerful instrument at their command astronomers wanted to peel away some of the mysteries of the Sculptor Galaxy. They are studying the myriad of cool red giant stars in the halo that surrounds the galaxy, measuring the composition of some of NGC 253’s small dwarf satellite galaxies, and searching for as yet undiscovered new objects such as globular clusters and ultra-compact dwarf galaxies that would otherwise be invisible without the deep VISTA infrared images. Using the unique VISTA data they plan to map how the galaxy formed and has evolved.

A new technique for removing foreign bodies of the external auditory canal.

“Foreign bodies of the external auditory canal are a common and challenging problem. Several techniques have been described and utilized to remove the many objects placed in ears. The tightly wedged smooth round foreign body remains one of the most difficult to remove. A new method, using a cyanoacrylate adhesive (Super Glue) was used successfully to remove a soy bean in a 16-year-old male. The glue was placed on the blunt end of a cotton swab, which was then introduced into the canal to make contact with the bean. Removal was easy, safe, and effective. This procedure avoided the morbidity associated with many well known techniques, eg, the use of forceps, and may have prevented removal under general anesthesia.”

A novel approach to the removal of superglue from the ear.

“The ability of superglue (a cyanoacrylate adhesive) to bond strongly and quickly to skin presents considerable problems when it is inserted into the ear. A case of a patient who inadvertently self-administered Bostik superglue into her left external auditory meatus is reported. The superglue was removed successfully, in the form of a cast, with warm three per cent hydrogen peroxide without damaging the meatus or the typanic membrane. The use of hydrogen peroxide to remove superglue from the ear has not been described previously.”

Photo: flickr/darkpatator

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Eye Color Predicts and Doesn’t Predict Perceived Dominance. First, the study replicates the common finding of some differences in perceived dominance between blue vs. brown-eyed males. But, they observed that when the eye colors were digitally manipulated the dominance ranking did not change. In other words the eye colors seem to have correlated with other traits of masculinity, rather than been a causal signal. The authors offer up a model whereby socialization of blue eyed individuals for longer periods as children (because the trait is neotenous) produces less facial masculinization. But I don’t buy the idea that this couldn’t be genetically mediated by variation on the HERC2/OCA2 locus (where most blue vs. non-blue eye color variation is controlled). In particular, I believe there’s a body of literature that melanin and testosterone production pathways affect each other so that there is a positive correlation, though the exact causal connections are still to be worked out. Note that all this only applies within populations; between population complexion differences don’t necessarily predict dominance differences because the genetic variates are not controlled as they are within populations.

Were The Americas Settled Twice? In the USA this scientific question has social-political implications, as Native American/Amerindian political rights have become excessively (to my mind) connected to self-identity as primal autochthons. Doing a reductio ad absurdum on this is too easy.

Population size predicts technological complexity in Oceania. This sort of result has obvious general implications (see McNeill and McNeill’s The Human Web). I assume Garett Jones would not be surprised.

Google Scholar Blog.

How to always have interesting conversations. Interesting is obviously a relative term. Additionally, probably best to apply a two-tier strategy. Tier-1 involves avoiding expending time/energy talking to boring people outside of cognitive autopilot, and tier-2 involves seeking out those with common interests among the non-boring set.

Is the human brain in final jeopardy?

Last April IBM announced its newest plan to crush humans in the gaming sphere: After taking us to task at chess, it would conquer us at “Jeopardy!” Since then the game show-playing robot, Watson, has been in development (cue 80’s training montage featuring computer programmers). J-Day approaches, and this fall the battle should commence.

The Game

In a lengthy New York Times Magazine feature on Watson this week, some of the details of the match became clear. It will take place this fall on national television.

Watson will not appear as a contestant on the regular show; instead, “Jeopardy!” will hold a special match pitting Watson against one or more famous winners from the past. If the contest includes Ken Jennings — the best player in “Jeopardy!” history, who won 74 games in a row in 2004 — Watson will lose if its performance doesn’t improve. It’s pretty far up in the winner’s cloud, but it’s not yet at Jennings’s level… The show’s executive producer, Harry Friedman, will not say whom it is picking to play against Watson, but he refused to let Jennings be interviewed for this story, which is suggestive [The New York Times].

The Preparation

If you’ve always yearned for “Jeopardy!” to feature the same kind of obsessive game-planning and secrecy as professional sports, this is your time. While folks on the show’s side won’t reveal the human contestants, the folks on the IBM side are busy testing Watson against humanity in mock “Jeopardy!” games. They even found a fake Alex Trebek (and no, it’s not Will Ferrell).

I.B.M.’s scientists began holding live matches last winter. They mocked up a conference room to resemble the actual “Jeopardy!” set, including buzzers and stations for the human contestants, brought in former contestants from the show and even hired a host for the occasion: Todd Alan Crain, who plays a newscaster on the satirical Onion News Network [The New York Times].

The Words

Deep Blue didn’t need words. Chess is a game of math and strategic logic, a game reducible to numbers and therefore ideally suited to an IBM supercomputer. “Jeopardy!” is something different: It may reward machine-like memorization of trivia, but you have to understand what you’re being asked before your brain can go get it. That’s the AI problem for Watson’s creators.

The biggest hurdle machines have to overcome in truly glorious human pursuits such as “Jeopardy!” is to gain an instinctive appreciation for natural language. It’s the puns, the jokes, the linguistic idiosyncrasies that have tended to stifle the most ambitious of machines. However, Harry Friedman, executive producer of “Jeopardy!,” was effusive in this IBM video. “I think we’ve gone from being impressed to blown away” [CNET].

Watson’s proficient even at those groan-inducing “Before and After” clues. Perhaps because it has no feelings.

The Potential

Winning on “Jeopardy!” is, of course, the pinnacle to a life’s work, but the supercomputer Watson might achieve more than racking up enough winnings to finally afford that New Zealand vacation. Computers that could just understand and correctly interpret your query and find answers would be an enormous advance, says IBM’s David Ferrucci.

Ferrucci was never an aficionado of “Jeopardy!” (“I’ve certainly seen it,” he said with a shrug. “I’m not a big fan.”) But he craved an ambitious goal that would impel him to break new ground, that would verge on science fiction, and this fit the bill. “The computer on ‘Star Trek’ is a question-answering machine,” he says. “It understands what you’re asking and provides just the right chunk of response that you needed. When is the computer going to get to a point where the computer knows how to talk to you? That’s my question” [The New York Times].

Computers that get subtlety? Humanity, I hope you enjoy parting gifts.

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Image: Jeopardy!

It’s Optenet’s business to find porn and, apparently, they’re pretty good at it. In a recent press release, the company that offers family-friendly filters for your computer claims that one-third of internet is porn.

Ana Luisa Rotta, director of child protection projects at Optenet, says in the release:

“When you consider that more than one third of the Internet’s content is pornographic, combined with the overwhelming increase in young people now curiously visiting Websites with such ease of access, it is becoming increasingly imperative that adults take responsibility for the management of home PC security.”

“Home PC security”? Was that a subtle reference to Homeland Security? We don’t know, but according to Optenet we’re all in danger. Their study, which looked at “a database of hundreds of millions of URLs,” churned out these stats:

-Pornography makes up 37% of the total content on the Internet
-Websites related to online role-playing games (RPGs) have grown by 212%
-Websites that contain violence have increased by 10.8%
-Websites that contain terrorism content have increased by 8.5%
-Websites that contain illegal drugs purchase have increased by 6.8%

An excellent point made on the blog Geeks Are Sexy, which broke the story: if these numbers only reflect the total number of sites in each category, then an increase doesn’t really mean much of anything. If the whole internet is getting bigger, then of course the number of each type of page on the internet is also increasing.

One wonders if that huge database also showed an increase in more wholesome websites–for example, corporate pages for porn filtering businesses.

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Image: flickr / gcfairch

I just got back from a European trip, and I have to say I did not miss tipping. I especially appreciated not having to do the song & dance typical of larger groups in sit-down restaurants in the USA where you figure out how much you’re going to tip on a communal basis, when everyone has different tipping set points and perceptions of service and such. The money is less of an issue than the extra wasted time at the end of a meal & drinks which are spent on the terms of calculation rather than more conventional conviviality. In fact now that I think about it way too much time in my life has been spent discussing the etiquette of tipping, often outside of a situation where people are going to have to tip imminently. I thought about this after seeing this post in The Atlantic on tipping. One correspondent observes:

I lived in Japan for a while. There is no tipping there, and it works great. If we could be like Japan, I’d be all for it. However, I don’t think we’d be like Japan. Anytime I have ever eaten somewhere that does not practice tipping, service has been abysmal. Customers herded through like cattle, dishes brought out late, then diners rushed through them, eyes rolled, etc. We just do not have the service culture that would allow us to disconnect pay from performance and continue to expect the same kind of service.

The point about national culture is well taken. I experienced some bad service in Italy and Finland, but the quality of badness was very different, in keeping what with you’d expect from the respective national cultures (though in general I experienced service as good as in the states in both places).* But the empirical observation about American restaurants without tipping having lesser service suffers from sampling bias. Establishments which don’t have tipping are generally lower-end, verging on cafeterias. So it’s not an apples to apples comparison. A better one would be looking at higher end restaurants which have mandatory gratuities for large groups vs. those which do not. Even here you have the peculiar distortion of the larger group, which can often be more difficult for a server to manage.

Of course one’s perspective on this probably varies by the amount of disposable income one has. If you don’t have much disposable income the small but repeated investments of time & energy which go into tipping might be worthwhile if you can manage to pay less than you would otherwise. If you have a fair amount of disposable income the marginal potential savings introduced by greater price variation which you can control at the cost of time & energy needed may not be worth it.

* I had to bargain very hard with a Finnish server on whether I could handle Indian levels of spiciness. This was obviously a well rehearsed conversation on her part, but I thought she should have updated her priors in my case. The lighting was dim, but not that dim. Usually American servers at Indian restaurants aren’t too resistant when I assert I can handle high levels of spice.

When it comes to research on HIV and AIDS treatments, it can be hard to know when to celebrate a small advance–everyone wants to see progress, but so many experimental avenues that seemed promising have turned out to be dead ends. Still, a new study that tried a sophisticated form of gene therapy as an HIV treatment seems cause for cautious optimism. If it bears out under further testing, the technique could lead to a one-shot, long-lasting treatment that could replace the punishing regimen of daily medications.

Treating HIV currently comes down to controlling the viral load with a mixture antiretroviral drugs, but over time, this drug cocktail becomes less effective. Researcher John Rossi and his colleagues tried to craft a more permanent treatment by genetically modifying the HIV-infected patients’ own blood stem cells and increasing the cells’ ability to fight off the virus. The researchers weren’t able to truly combat the virus in this experiment–the patients’ viral loads remained the same–but their work moved beyond previous attempts in two ways: They successfully modified blood stem cells by giving them anti-HIV genes, and those cells survived for two years in patients.

Earlier clinical studies the group conducted with the same strategy made little headway, but now the researchers have overcome two key obstacles, says Rossi, a molecular geneticist. One is that they managed to stitch the anti-HIV genes into a high percentage of the appropriate stem cells. The other is that the cells lived for a long time. “If we could increase the number of modified cells by 10- or 100-fold, we might be able to stop the virus itself,” says Rossi. [ScienceNow]

The small study published in Science Translational Medicine tested the safety of the technique for HIV-infected patients, and served as a proof of concept. The four patients in this study were undergoing therapy for AIDS-related lymphoma at City of Hope cancer center in California. Part of the usual treatment for this condition is to remove blood stem cells (found in bone marrow) before cell-damaging chemotherapy, and to then return them after treatment. Researchers wanted to test their virus-fighting cells’ survival skills, so with each patient’s normal blood stem cells, the researchers also reintroduced a small number of modified cells.

They modified the cells in three ways: They boarded up the cells’ doors to keep the HIV virus out, and made two genetic changes to the cells’ internal defenses so that the virus would have a harder time copying itself if it made it through.

[T]he team added three genes to the immune stem cells’ DNA: one that cripples the CCR5 receptor that HIV exploits to enter the cell (this mimics a successful transplant recently done in Berlin with a much discussed patient who apparently was “cured” of his HIV infection), and two others that disable viral genes and prevent HIV from copying itself. This makes it increasingly difficult for HIV to find new targets and mops up any new virus produced [ScienceNOW].

As a safety precaution, the researchers didn’t implant enough of these novel cells to test how well they might fight the virus, but they did get a glimpse of how long the modified cells could stay in a person’s system. Up to two years after the treatment, patients still had low levels of these special cells.

“That’s a major finding,” Rossi added. While the number of cells expressing those genes was too low to provide any therapeutic benefit, it’s “proof of principle” that gene therapy may provide long-term HIV treatment, he said. [The Scientist]

As a next step, researchers hope to implant a greater number of modified cells in patients, to see how well they can fight and how long their defenses hold.

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Image: flickr / euthman

On November 26-28, 2010, the very first official TAM Australia will be held in Sydney! The Aussie skeptics have put together that website to give you all the info you need on the meeting, including the current guest list and all that.

Registration starts on June 20 for members of the JREF and the Australian Skeptics, and then open to the public two weeks later.

I was in Australia for the national skeptics conference in 2004, and had just about the best time of my life. If you’ve never been, now’s your chance to kill two birds with one stone. And you can bring me back Minties.

There’s a war going on that you’re completely oblivious to, even though it’s happening right under your nose. Well, actually, inside your nose. Rival species of bacteria compete for precious real estate within the damp linings of your nasal passages. In some cases, this microscopic combat works in our favour, when harmless species repress the growth of deadlier ones. But not always – sometimes a species can only gain the advantage over its competitors by becoming more virulent, and we suffer collateral damage.

Elena Lysenko from the University of Pennsylvania has discovered one such rivalry, at least within the noses of mice. She studied the conflict between two species of bacteria – Haemophilus influenzae and Streptococcus pneumoniae, both of which can cause pneumonia, meningitis and other human diseases.

S.pneumoniae spends much of its time in our noses without causing any harm. Only in a minority of carriers does it gain the potential to cause diseases, such as pneumonia and sepsis. But that doesn’t make any sense, because these conditions are potentially fatal but not contagious. The bacteria risk killing their host (and by extension themselves) without gaining the opportunity to colonise a new one. Why would they go down this dead end route? Lysenko thinks she has an answer – S.pneumoniae turns nasty as a side effect of its tussle with H.influenzae.

There’s not enough space in a nose for these two bacteria. H.influenzae plays dirty – it actually summons our own immune system into battle, setting white blood cells called neutrophils against S.pneumoniae. This call-to-arms is so effective that in most cases, H.influenzae can completely oust its rival from a nose.

But S.pneumoniae has a defence. The bacterium is surrounded by a sugary capsule and there are at least 90 different types of these coats. Some of them are particularly thick and they act as suits of armour that protect the bacterium against white blood cells that try to engulf it. Encased in these shields, S.pneumoniae can evade the host’s immune system. It neutralises H.influenzae’s secret weapon but it also gains the ability to invade other tissues and cause serious diseases.

Lysenko demonstrated the effects of this battle using both mathematical models and experimental evidence. When she incubated H.influenzae with different strains of S.pneumoniae, she found that only those with armoured shells could hold their ground against their competitor. Strains without these thicks shells were soon driven out. And just to show that this competitive edge wasn’t due to the genes carried by different strains, she managed to turn a weedy strain into a tough one by transplanting an armoured shell onto it.

But why doesn’t S.pneumoniae use its armoured shells all the time? To find out, Lysenko pitted the different strains against each other in the absence of any other competing species. This duel revealed that the armoured strains are actually inferior to non-armoured ones in terms of colonising the nose. Presumably, making a heavy shell takes up a lot of energy, which means that these well-defended strains can’t grow as quickly as other more vulnerable ones.

They only gain the upper hand when H.influenzae is around. At that point, the ability to resist death by white blood cell more than makes up for their natural disadvantages. And of course, the armoured strains, by shrugging off attacks from the immune system, are better at causing invasive infections than their mild-mannered cousins.

Of course, Lysenko has only demonstrated that this happens in mice but it is likely that similar competitions operate in human noses. And that’s fascinating – it means that many human diseases really have nothing to do with us at all. They’re the result of battles waged between different species of bacteria, and we just happen to be caught in the crossfire.

Reference: Current Biology http://dx.doi.org/10.1016/j.cub.2010.05.051

More on bacteria:

• Fighting bacteria with bacteria – common nose germ provides new weapon against superbugs
• Bacteria on your keyboard point to your identity but forensic value is unlikely
• When enslaved bacteria go bad
• The bacterial zoo in your bowel
• Cooperating bacteria are vulnerable to slackers
• Bacteria and languages reveal how people spread through the Pacific

Reihan Salam points me to a presentation by a Facebook executive who claims that “E-mail…is probably going away….” Well, remember Google Wave? I assume that email-as-we-know-it will evolve. But one thing I pointed out to a friend the other day: remember when you were excited to get “new mail?” (perhaps the reference will be lost on younger readers, but there was a time when it was cool and special to have an email account, and be able to receive messages from people who lived in Ecuador at digital speed) Now it’s more like, “now what!?!?!” Email is a utility through which your boss may contact you. The excitement factor has now shifted to Facebook, where old friends you’ve lost touch with may request to be your friend. But if Facebook becomes as ubiquitous as email, as taken-for-granted, you might start getting wall messages from your boss. And at that point Facebook will become a utility you’ll want to not log into, not because you want to avoid wasting time procrastinating, but because the “real world” has infected it.

Technology has been one reason we humans have by and large broken out of the Malthusian trap. But a key difference between innovation on the physical dimension (e.g., the combustion engine) and technologies which have social utility is that human psychological faculties can shift only on the margins by much smaller degrees. In theory you can have as many Facebook friends as Facebook will allow you to have; it’s a scalable phenomenon. But in reality a small circle of friends become Facebook “friends” who you barely know, because your mind isn’t geared to really keep track of so many social relations.

Of course the people who run tech companies are smart and many know this. But their jobs hinge on you becoming invested in the idea that their firm is going to Change Everything. So they’re not going to emphasize too much the fact that human utilization of technology is substrate constrained, so to speak.

This is a guest post from a member of Science in the News (SITN), an organization of PhD students at Harvard University whose mission is to bring the newest and most relevant science to a general audience. For over a decade, SITN has been presenting a fall lecture series at Harvard Medical School, with talks on a diversity of current and newsworthy topics, such as stem cell biology and climate change. SITN also publishes the Flash, an online newsletter written by graduate students at Harvard, which presents current scientific discoveries and emerging fields in an accessible and entertaining manner. SITN engages in additional outreach activities such as "Science by the Pint", and hopes students at other institutions will also make the commitment to strengthen science communication. The following post is from Harvard graduate student Amanda Nottke. How Do We Identify Extinct Species? Paleontologists have always differentiated between extinct species by comparative anatomy of their fossil remains. Those scientists who study living organisms have an additional technique available – the comparison of DNA sequences between specimens. More recently, due to rapid advances in the efficiency and reduced cost of DNA sequencing, it has become possible to sequence DNA extracted from the remains ...

Behold La conversione di San Paolo (The Conversion of St. Paul), one of the masterworks of Caravaggio. The Italian artist of the Baroque era was famous for the chiaroscuro shading—dramatic contrasts of light and dark—evident in this conversion scene. But he was also renowned for living hard and dying young. Four centuries after his death, Italian researchers say they’ve found his bones, and they might know what actually killed him: the lead in his paints.

First, the researchers had to find his remains. Caravaggio died in 1610 in the Tuscan town of Porto Ercole, but his remains were whereabouts unknown until a researcher claimed to turn up a death certificate in 2001 pointing to the crypts there. The bones the scientists found there matched a man aged 38 to 40 (Caravaggio’s age range at his death) and dated to his era. And the DNA matched combinations found in people from the painter’s hometown and sharing his original surname, Merisi or Merisio.

“There can’t be the scientific certainty because when one works on ancient DNA, it is degraded,” Giorgio Gruppioni, an anthropologist on the team, told The Associated Press. “But only in one set of bones did we find all the elements necessary for it to be Caravaggio’s — age, period in which he died, gender, height.” The group says there is an 85 percent probability they are right, though team leader Silvano Vinceti says that is conservative. “We are being cautious,” he said. “As a historian I can say we have found the remains… All evidence concurs” [AP].

The bones in question carry a high concentration of lead, which convinced the researchers that Caravaggio—known to be messy with paints—unknowingly could have given himself lead poisoning.

Despite the romantic allure of “dying for one’s art,” the explanation is fairly tame compared to the more exotic ends that Caravaggio’s wild reputation suggested.

Michelangelo Merisi, known as Caravaggio after the Lombardy town where he grew up, was a young man at the height of his career in Rome when he killed a man in a brawl in 1606, fleeing to find new patrons in Naples and then Malta, only to be thrown off the island two years later for more brawling. “After a fortnight’s work he will swagger about for a month or two with a sword at his side and a servant following him, from one ballcourt to the next, ever ready to engage in a fight or an argument,” wrote one observer [The Guardian].

Rumors persisted the that painter died of malaria or syphilis, or perhaps crossed the wrong person and wound up murdered. Of course, the DNA-sampling researchers are only 85 percent sure their find in truly Caravaggio. So maybe he really did meet a more operatic end.

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Image: Wikimedia Commons

A ladybird larva is on the prowl on a witch hazel plant. The youngster is a voracious predator and it’s hunting for aphids. It seems to have found a bountiful feast – a swollen structure called a gall that houses an entire aphid colony. With so many meals in one place, the colony seems easy prey, but it has staunch defenders.

As the ladybird approaches, aphids pour out of the gall and grab the predator by their jaws and legs. It’s a suicide defence. The aphids secrete massive amounts of waxy liquid from their bodies, which quickly solidifies and glues the ladybird to the plant. Unable to walk or bite, the ladybird dies and the aphids go with it. In the video below, you can see what happens when one of these aphids is prodded with a needle.

There is more to these suicidal protectors that meets the eye. Keigo Uematsu and University of Tokyo found that all of them are ‘menopausal’. They are the parents of the other aphids in the gall but their reproductive days are long behind them. With no further opportunities to raise the next generation, their final role is to defend their offspring, with their lives if necessary.

Many species of aphids live in galls, stimulating the plants they suck to form large, hollow chambers. These species tend to be cooperative and social, a more basic version of the supersocieties of ants and termites. They all have special ‘soldier’ individuals, who are tasked with defending the colony, repairing the gall and keeping it clean. Some do this at the cost of their own lives. Last year, another Japanese team discovered that the gall aphid Nipponaphis monzeni employs suicide-plasterers, individuals who repair holes in the gall by fatally leaching their own bodily fluids onto the hole.

Quadrartus yoshinomiyai is another gall-forming species whose soldiers have sticky fluids and suicidal tendencies. Its galls are formed on witch hazel by a single founding female, who initially seals herself away. This matriarch produces a line of wingless clone offspring, who then mate with one another to give rise to another generation of winged adults. All this takes around two years. Come mid-spring, the aphids cut an exit hole in the gall and the winged generation fly away to another host plant – the sawtooth oak.

The wingless middle generation are the ones who conduct suicide campaigns against attacking predators. By cutting into freshly collected galls, Uematsu found that these wingless adults tend to be clustered near the exit holes. When she set ladybirds upon these defenders, she found that more than half became stuck in an aphid pile-on, their jaws and legs gummed up with wax. Only 23% managed to infiltrate the gall. If the wingless adults were removed, only 14% of ladybirds were glued down, and 64% entered the gall.

Through April, as the winged aphids leave their homes, the wingless adults stay behind to defend the remaining colony. At the point when the gall opens, the wingless aphids go through menopause. They lose the ability to reproduce but they don’t die immediately – instead, they shift from sex to defence.

Virtually all aphids carry mature embryos if they’re still capable of breeding but when Uematsu dissected the defenders, less than 5% of them contained embryos. Instead, their abdomens were almost exclusively taken up by their defensive waxy liquid. Rather than producing embryos, they had devoted their energies towards producing wax. They still get benefits though, for their suicidal actions ensure that their young, who carry their genes, are more likely to survive.

This is subtly different to the situation in many other social insects, where some individuals never reproduce for the sake of helping their relatives who do. Nonetheless, there are other examples of insect menopause. The ant Pristomyrmex punctatus permanently shifts from reproduction to foraging as it ages. And in some paper wasps, individuals fight for dominance and the losers give up the right to reproduce and act as workers instead.

Reference: Current Biology http://dx.doi.org/10.1016/j.cub.2010.04.057

More on aphids and menopause:

• Did conflict between old and young women drive origin of menopause?
• The heavy cost of having children
• Aphids defend themselves with chemical bombs
• The suicide plasterers – aphids that repair their homes with their own bodily fluids
• Aphids got their colours by stealing genes from fungi