Thursday, July 09, 2015

Good Hygiene Counts In Wild

BY NATALIE ANGIER


Northern flickers have a poor division of domestic labor.

Among these tawny, 30-centimeter woodpeckers with downcurving bills, the male flickers are more industrious housekeepers than their mates, according to a new report on their sanitation habits in the journal Animal Behavior.

Researchers already knew that flickers, like many woodpeckers are a sex role reversed species. The fathers spend more time incubating the eggs and feeding the young than do the mothers. Now scientists have found that the males’ parental zeal also extends to nest hygiene: when a chick makes waste, Dad is the one who usually picks up the unwanted presentation and disposes of it far from home.

“It takes away microbes, removes smells that might alert predators, and makes the whole nest much cleaner,” said Elizabeth Gow, a postdoctoral fellow at the University of British Columbia and an author on the new report. “It’s an important aspect of parental care that we often forget about.”

The new work reflects a growing interest in what might be called animal sanitation studies-the exploration of how, why and under what conditions different species will seek to stay clean, stave off decay and formally dispose of the excreted and expired. Nature may be wild, but that doesn’t mean anything goes anywhere, and many animals follow strict rules for separating metabolic ingress and egress, and avoiding contamination.

Researchers have identified honeybee undertakers that specialize in removing corpses from the hive, and they have located dedicated underground toilet chambers of African mole rats.

Among chimpanzees, hygiene often serves as a major driver of cultural evolution, and primatologists have found that different populations of the ape are marked by distinctive grooming styles. The chimpanzees in the Tai Forest of Ivory Coast will pick a tick or other parasite from a companion’s fur and then squash it against their forearms.

Chimpanzees in the Budongo Forest of Uganda prefer to dainty place the fruits of grooming on a leaf for inspection, to decide whether the dislodged bloodsuckers are safe to eat, or should be smashed and tossed. Budongo males, those fastidious charmers, will also use leaves as “napkins,” to wipe their penises clean after sex.

Serious sanitation work can be time-consuming and dangerous, as the new study of flickers revealed. Baby woodpeckers deposit their waste in fecal sacs, the mess contained in a gelatinous outer coating “like a water balloon,” Dr. Gow said. “It makes for easier removal from the nest.”

The little birds can be prodigious sac factories. Where human parents may change 50 to 80 diapers a week, flicker parents remove the same number of fecal sacs a day, each time venturing some 90 meters from the nest and risking exposure to predators like hawks.

Dr. Gow determined that father flickers performed about 60 percent of the sanitation runs, spent up to an hour a day on the task and, in the event of the untimely death of a mate, were happy to let the sacs stack up. “When they’re really strained,” Dr. Gow said, “and the option are remove fecal sacs or feed the kids, they’ll feed the kids.”

Good hygiene is a matter of context. Luigi Pontieri of the Centre for Social Evolution at Copenhagen University and his colleagues study the pharaoh ant.

Unlike most ants, pharaoh ants don’t build structured nests or defend territory. “They’ll live wherever they can, in places other ants avoid,” Dr. Pontieri said. “They’ll live in trash, in layers of old food, in electric plugs, between the pages of books. You can even find a colony inside a mealworm, which they ate their way into.”

Sometimes, Dr. Pontieri said, “it can be really disgusting to work with these ants.”

Delving into the secrets of the ant’s capacity to stay healthy no matter where they roam, the researchers discovered that the insects seemed to resist disease in part through a kind of vaccination program.

As the researchers reported in the journal PLOS One, when the ants were given a choice between nesting in clean soil or soil littered with the corpses of pharaoh ants killed by fungal disease, the living ants chose to nest with the fouled fallen.

Uninfected cadavers didn’t hold the same appeal; the pharaoh ants wanted dead comrades with spores.

We think the ants were actively seeking small doses of the pathogen,” Dr. Pontieri said. “It might be a way of getting immunized against a disease that could kill them.”

Yet stable property can have its benefits. Gene E. Robinson, a professor of neurology and entomology at the University of Illinois, said that when formerly free-living honeybees first “took the show indoors” by constructing thermally controlled hives, they gained the power to coddle their young but faced new challenges of hygiene.

“Dead bees that once dropped harmlessly to the ground could now accumulate in the hive,” Dr. Robinson said.

The social insects solved the problem by establishing a tiny corps of undertakers: bees in late middle age and of a particular genotype that has yet to be decoded.

African mole rats build lavatories. When one toilet chamber is too full, said Chris G.Faulkes of Queen Mary University of London, the workers will “backfill it, seal it up and make a new one.”

Like its human equivalent, a mole rat toilet chamber is also a place to primp, and a freshly relieved animal will mark its recent visit with a touch of anogenital fluid daubed on the bathroom floor.

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Taken from TODAY Saturday Edition, The New York Times International Weekly, July 4, 2015
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