Cricket sex video reveals wild mating behavior

4th June 2010, Comments 0 comments

Armed with dozens of infra-red cameras, British scientists have gained unprecedented insight into the love life of crickets, whose wild behavior was revealed in a study released Thursday.

For this "Big Brother" in the wild, University of Exeter biologists trained 96 cameras and microphones on a meadow in Asturias, northern Spain -- home to some 152 Gryllus campestris field crickets.

Any movement or sound the crickets made during the breeding season triggered the audiovisual equipment.

A tiny numbered placard, just large enough for the camera to read, was super-glued on the back of each cricket. A miniscule piece of tissue was also used to create a DNA fingerprint of each creature.

In addition to "unbroadcastable goings-on," the scientists learned that males not only sing to attract females, but actually set off on "mating safaris."

Pairs mate up to 40 times, while females also slip out for quick liaisons with males nearby before returning to their regular mates.

For their study, published in Friday's issue of the journal Science, the biologists gathered 250,000 hours of intimate video footage, and used the DNA fingerprints to determine the number of offspring each individual cricket left in the next generation.

After they mate, the females inject their eggs deep into the soil and fight many battles to secure the site and avoid predators. Surviving females will have laid hundreds of eggs each by the following summer, but few leave any descendants.

Even the most successful females will only have a handful of offspring that survive to maturity.

Male crickets have an even smaller rate of success, with most leaving no heirs and only a few having many to their name.

The study also found that seductive ability and the capacity to procreate do not always go hand in hand. Dominant males had fewer mates than those who lost more fights, but left the same average number of offspring.

While males that sang for longer secured more mates, only smaller crickets had to sing in order to ensure they would have more offspring -- females apparently favored stronger males.

Both males and females had more offspring when they had a greater number of mating partners.

"Song doesn't seem to matter much to the success of bigger and longer lived males, perhaps because females don't worry about what a male sounds like if he looks good in other ways," University of Exeter post-doctoral researcher Rolando Rodriguez-Munoz said.

Exeter biologist Tom Tregenza, explained that "the cricket soap opera is a model of the life struggles of so many species; it tells us about how natural selection happens in the wild."

He stressed the importance of understanding how ecosystems such as the crickets' meadow would respond to climate change, to determine whether existing populations would adapt or be replaced by new species.

"These are tough questions and we need to directly observe how behavior affects reproductive success. And we're seeing a lot of wild behavior that has never been seen on TV before!" added Tregenza.

© 2010 AFP

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