Male fireflies that try to attract mateswith a flash of light also seduce the females with a gift -- a spermatophorepackage or a capsule containing sperm and nourishment for the female.
Researchers from Tufts University in Boston, US, found that females preferredmales that had the largest, most nourishing gift, BBC reported. The teampresented their findings at the First Joint Congress on Evolutionary Biology inOttawa, Canada.
Sara Lewis, who has been studying fireflies for 20 years, and Adam South usedLED lights to mimic the flashes of "amorous" male fireflies, thereport said.
The scientists showed one group of females the artificial male flashes inpatterns and durations that had been proven attractive in previous studies.
Another group of females saw "unattractive" flashes.
In the wild, females are very "picky" about which males they revealthemselves to during the courtship. Females only "flash back" tomales they are attracted to.
In the experimental set-up, after several minutes of the courtship flashing,males and females were paired together in miniature chambers.
The scientists filmed the incident under infrared illumination to see what washappening when the lights went out.
The video footage revealed that females were more likely to mate with malesthat had larger nuptial gifts to offer.
Once the males and females were together, the quality of the flashes did notseem to affect the outcome of their meeting.
However, since the spermatophore is transferred internally, it was not clearhow the female uses the size of this gift to decide whether to mate with amale.
South said "attractive flashes only seem to benefit males during the earlystages of firefly courtship".
"Initially, flashes are important. But once males make physical contact,females switch to the alternative cue," he said.
"If we had stopped studying the mating habits of fireflies after theflashing stopped, we would have missed this amazingly complex and incrediblestory," he said.
Other insects that accept gifts are female Paratrechalea ornata spiders thatreceive food parcels wrapped in perfumed silk from suitors, while the malefruit-fly or Drosophila subobscura regurgitates a nutritional soup for itsfemale.