NatureWrap: Gentoos may be four not one

Gentoo penguins (Pygoscelis papua) should be reclassified as four species, according to British scientists who analysed populations in different areas in the Southern Hemisphere.

The two existing subspecies, P. p. ellsworthi and P. p. papua, should be raised to species level and two new species created, they suggest in a paper in the journal Ecology and Evolution.

Jane Younger and colleagues from the University of Bath looked at the genomes of gentoo populations in the Falkland Islands and South Georgia in the southern Atlantic Ocean, the South Shetland Islands in the Antarctic and Kerguelen Islands in the Indian Ocean.

When they combined genomic data with measurements of museum specimens, they found clear morphological and genetic differences between the four populations – not surprising, they suggest, given they live in different latitudes and have adapted to different habitats.

“Gentoos… have become geographically isolated from each other to the point where they don’t interbreed with each other, even though they could easily swim the distance that separates them,” Younger says.

Counting them as four separate species will aid in their conservation, the researchers say, because it will make it easier to monitor any decline in numbers.

Reclassification is not a new idea. In 2016 it was revealed that there are four genetically distinct species of giraffe.

Get some acid into you

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An ant trying to swallow formic acid from the acidopore on its abdomen. Credit: Simon Tragust

Some ants swallow their own acid to protect themselves from germs, according to German researchers. The formic acid kills harmful bacteria in the food they’ve eaten and also influences their intestinal flora, a team from Martin Luther University (MLU) and the University of Bayreuth writes in a paper in the journal eLife.

Through several experiments, the researchers were able to show that ants essentially disinfect themselves on the inside. “When the ants were able to access the acid, their chances of survival increased significantly after eating food enriched with pathogenic bacteria,” says MLU’s Simon Tragust.

Formic acid, one of the simplest organic acids, is produced in a special gland in the abdomen of many species of ant. Humans and a few other vertebrates are the only other animals with extremely acidic stomachs (and in the case of humans, the acid is produced in the stomach).

The results of the new study explain, Tragust says, why some ants have very few bacteria in their digestive tracts; those that are present are primarily acid-resistant microbes. “Acid swallowing acts as a filter mechanism, structuring the ant’s microbiome.”

How formic acid precisely works is still a mystery, but it and other organic acids have long been used as additives in animal feed to kill harmful germs.

Maturing as required

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A dominant gelada male and his females. Credit: Jacinta Beehner

Female geladas – close relatives of baboons found only in the highlands of Ethiopia – are more likely to mature right after a new breeding male arrives, even if it means maturing earlier than expected, a new study suggests.

However, others – often the daughters of the primary breeding male prior to the new male’s arrival – mature later, the researchers write in a paper in the journal Current Biology. This suggests they can time their maturity to avoid inbreeding.

“Once their father is ousted by the new male, they appear to… immediately mature,” says senior author Jacinta Beehner, form the University of Michigan. “Taken together, we see that a new male causes a really obvious increase in the number of maturations in a group – whether early, on time or late.”

The researchers kept track of the age at maturity for 80 females in the wild over 14 years, helped by the fact that it’s easy to tell when a gelada matures: they have very conspicuous “sexual swellings” on their chest and neck.

The study’s findings suggest, Beehner says, that maturation in primates may be more sensitive to social environments than scientists had thought.

“Many New World monkeys, such as the marmosets and tamarins, have long been known to be highly sensitive to social variables… but until now we had no evidence that Old World monkeys or apes were similarly sensitive to the presence or absence of particular individuals.”

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