HANOVER, N.H., June 16 (UPI) -- Male tree crickets belt out songs through the night in the hope of attracting a lover. Each song is different. But as Dartmouth College researchers recently found, each sex song burns the same amount of calories.
The discovery is demonstrative of the concept of biological trade-offs, whereby an advantage gained by an adaptive trait is paid for by a related disadvantage. For example, a louder mating call may attract more mates, but it also attracts more predators.
In the case of tree tickets, the trade-offs are related to caloric expenditure. Bigger crickets can generate louder songs, but belting them out requires a greater amount of effort. Thus, they can't be sustained for as long as smaller crickets, who may sing all night, but can only vocalize at moderate volumes.
Bigger crickets were characterized by longer syllables sung less frequently, while smaller crickets repeated shorter syllables for longer periods of time.
The trade-off in this scenario acted as a sort of adaptive plateau or glass ceiling -- ensuring calories burned stayed constant regardless of song or body weight.
"Physiology, physics and ecological interactions can generate trade-offs within species, but may also shape divergence among species," lead study author Laurel Symes, an evolutionary biologist at Dartmouth, explained in a press release. "Our findings are interesting because they are some of the clearest examples of biological trade-offs and suggest that evolutionary pathways may be tightly constrained."
The new study was published in the journal Evolution.