Washington, Jan 8 (ANI): Reflecting an 800-year-old Chinese text, researchers at the University of Toronto Mississauga have found that male crickets with larger heads and mouthparts make for more successful fighters against their smaller-headed rivals.
Chinese cultural tradition details a practice of observing and betting on cricket fights, which has given rise to a detailed list of characteristics that Chinese practitioners think make for champion fighters.
"Because money was involved, there was a strong incentive for the practitioners of this sport to observe their cricket fighters closely," said Kevin Judge, a biology postdoctoral researcher.
In fact, an ancient Chinese text mentions that the best cricket fighters have the largest heads.
In nature, male field crickets fight one another over territories and access to potential mates by using their pointed and pincer-like mouthparts as weapons.
In the study, Judge and co-author Vanessa Bonanno have shown that males with larger heads and mouthparts are more successful in fights with smaller-headed rivals.
They also showed that male field crickets have larger heads and mouthparts than females, which, according to Judge "makes sense given that female crickets don't fight over mates."
The study "tested theories of contest settlement and sexual selection, and how body shape has evolved to help males in competition with other males," said Judge.
Thus, they conducted two experiments to test the hypothesis that relatively larger weaponry acts as an advantage to males in aggressive contests.
Pairs of males were selected for differences in head size and consequently were different in the size of maxillae and mandibles.
In the first experiment, males were closely matched for body size (pronotum length), and in the second, they were matched for body mass.
Males having larger weaponry won more fights and increasing differences in weaponry size between males increased the fighting success of the male with the larger weaponry.
By examining weaponry, the study opened a new avenue by which researchers can understand aggression in field crickets.
The study was published in a latest issue of the online, open-access, peer-reviewed journal PLoS ONE. (ANI)