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Cleanest creatures skip the bathroom

Since fouling oneself is a major social faux pas that can create health and safety problems, the cleanest, most intensely social creatures are likely those that never expel bodily waste, suggests a new paper.
Image: Leafcutter ants haul plant bits in a row on the rain forest floor
Leafcutter ants are specialized castes whose member serve as lifelong poop collectors . National Geographic via Getty Im
/ Source: Discovery Channel

Scientists may not be able to prove that cleanliness is next to godliness, but they have just demonstrated that good sanitation promotes an individual's ability to live and get along well with others.

Since fouling oneself is a major social faux pas that can create health and safety problems, the cleanest, most intensely social creatures are likely those that never expel bodily waste, suggests a new paper that is one of the first to ever explore the simple and complex solutions different species have evolved to deal with personal waste management.

"It's probably not perceived as very glamorous to be conducting research that involves the manipulation of feces!" lead author Duncan Jackson told Discovery News. "It might not also sound too great in a CV or as a topic of dinner party conversation."

Jackson, a researcher in the Computational Biology group at the University of Sheffield, and colleague Adam Hart of the University of Gloucester put aside such reservations and compared how different organisms solve what may be called "the bathroom problem."

Their determinations are outlined in a paper accepted for publication in the journal Animal Behavior.

Humans wind up on the simpler side of the scale, which we share with rodents like naked mole rats that build latrine chambers to keep their waste isolated from eating and sleeping areas.

It's possible that the cleanest, most highly evolved creatures where this topic is concerned are internal parasites, along with bee, wasp and ant larvae. According to the researchers, all possess "a blind gut" that prevents continuous passage from the mouth to the anus and ensures that waste cannot be evacuated.

Certain parasitic wasps fall into this group, Jackson explained, because they have "the ability to retain feces rather than defecate in the host, which would affect host survival." He and his colleague believe this ability later allowed for the crowded, highly organized and very social living habits of bees, wasps and ants.

Larvae for these insects do not eliminate waste.

"This can last from weeks to months," Jackson said.

Just before or after the transformation from larvae into adult bug, the individual releases a very stinky pellet that contains all of the built-up waste. Either the individual or special workers move quickly to dispose of this fecal pellet, the meconium.

When a honeybee takes its first flight, it immediately releases its strong smelling meconium.

Without such a clean and easy solution, other social insects have evolved another waste management tactic — lifelong poop collectors. Both gall aphids and leafcutter ants have specialized castes whose members serve as these waste removers.

"They process the colony's garbage and once they start doing this job they remain in it for the rest of their lives, being shunned by other workers," Jackson said, adding that honeybees seem to have evolved a more democratic process, whereby workers can change jobs after they reach a certain age.

Stephen Martin, a postdoctoral researcher in Sheffield's Apiculture and Social Insect Laboratory, told Discovery News that the new paper is "refreshing," since other studies delving into the evolution of sociality mostly ignore the problem of waste management.

"Their idea that the blind gut might have been a very important facilitator of social evolution is certainly well supported by their review of the data," Martin said.

Jackson pointed out that "it's curious that this research area seems to be treated with amusement or revulsion by other researchers, and this is why its importance is so rarely acknowledged."