Mormon cricket cannibals


March of the Mormon cricket cannibals
22:00 27 February 2006
NewScientist.com news service
Jeff Hecht







Hunger for protein and salt is what gets millions of Mormon
crickets marching across western North America ? that, and a
fear of cannibals.

If they want to survive, the insects have to keep marching fast
enough to stay ahead of other hungry crickets that might eat
them for their own protein and salt content.

Mormon crickets ? Anabrus simplex ? are large flightless
grasshopper-like insects and not true crickets. Millions of them
sometimes march together, with dozens of insects per square
metre moving up to 2 kilometres per day, and covering an area up
to 10 kilometres long. Marching troops of the omnivorous insects
can cause serious crop damage, but unlike locusts they do not
devour all the plants in the landscape.

Curious to see if nutrition could explain this behaviour,
Stephen Simpson at the University of Sydney, Australia, studied
the crickets with Greg Sword at the US Department of
Agriculture's research service, and colleagues. They placed
samples of foods rich in proteins or carbohydrates on a cattle
trail in the path of the marching insects.

The crickets showed "a clear preference for protein-containing
food," with up to 13 crickets clambering over a 4-centimetre-
wide dish at once. They also went after salt.

Eat and be eaten
Foraging crickets prefer protein-rich sources such as seeds,
flower heads, and carrion. But there is not enough to go around.
"They get a lot from eating each other," says Simpson. "Mormon
crickets are walking packages of protein and salt." Any that
stop to eat have to weigh the risks of another cricket stopping
to eat them, he adds.

Indeed, the researchers found cannibalism to be common. "We
pulled the heads off to see what they were eating; a substantial
portion had evidence of other crickets inside them," Simpson
says.

Some protein-starved crickets devoured the entire bodies of
others their own size. "Some things can swallow other things
whole, but this is a chew-up-and-swallow meal," Simpson told New
Scientist.

The crickets do not swarm every year, only when there is not
enough food to go around. They evidently tolerate their cannibal
companions because the risks of going it alone are higher ?
within two days more than half of isolated insects were eaten by
other animals.

If a person is in motion the crickets do not bother them, but a
person might get in trouble by lying down in front of them,
suggests Simpson: "There's a horror movie in there somewhere."

Journal reference: Proceedings of the National Academy of
Sciences (DOI: 10/1073/pnas.0508915103)

.

Relevant Pages

  • Re: Mormon cricket cannibals
    ... Hunger for protein and salt is what gets millions of Mormon ... crickets marching across western North America? ... the insects have to keep marching fast ... about Mormon crickets before, ...
    (soc.retirement)
  • News: Mormon cricket cannibals
    ... Hunger for protein and salt is what gets millions of Mormon crickets ... marching across western North America - that, and a fear of cannibals. ...
    (talk.origins)
  • Re: Blight Resistant Potatoes
    ... Earthworms are 70% protein and soaking them in water overnight will ... Nigeria you can buy termite stock cubes. ... Scoop them off decomposed meat, ... Crickets can be an excellent and healthy ...
    (uk.rec.gardening)