The key component of your morning coffee may also provide a sex-drive boost for sterile insects, research suggests.
A team at Macquarie University has been adding caffeine to the diet of sterile fruit flies, hoping to increase sexual maturation speed and boost mating times.
Queensland fruit flies (Q-fly) cost Australian farmers an estimated $300 million in lost markets each year, according to industry group Hort Innovation.
Researcher Saleh Adnan said increasing the sex drive of sterile Q-flies would more effectively spread infertility in the pest population.
He said the boost came from the rapid increase in reproductive organ size from consuming caffeine.
"Sterile males released from the facility find a wild female and transfer their sterile ejaculate, making sure the female is sterile for the following generation so there will be no further infestation," he said.
"To make that happen, one of the most important things is that the male you're releasing is sexually active.
Caffeine is key
Mr Adnan said the faster the flies became sexually active, the higher the level of success.
"[We thought] why don't we add something really interesting that has stimulatory power?" he said.
"There isn't any information about how caffeine impacts the reproductive organs of any living organism."
Caffeinated Q-flies became sexually active in six to eight days, compared to 10 to 12 for normal Q-flies, he added.
"They have a high level of mating, and longer mating, which makes sure that they are effectively transferring their ejaculate to the wild females."
The sterile insects were fed a standard diet of sugar and protein with 0.5 per cent of caffeine added.
"We also did the longevity test, where we tried to understand whether the caffeine affects their longevity and if they may die sooner," Mr Adnan said.
"[But] caffeine feeding changes their sexual behaviour, it does not have any negative impact on their survival.
"[The insects have] multiple mating in their lifetime, so males that start mating faster have a high possibility of mating more females."
Benefit for farmers
Hort Innovation said Q-fly continued to be an issue for Australia's $13.2 billion horticultural industry and could impact a range of fruit and vegetable crops.
Mr Adnan said increasing the time for fruit flies to become sexually active meant they could have a more thorough effect on the wild population.
"The caffeinated males will release their sperm to the females who are really destructive," he said.
"Then, they're not destructive anymore so their infestation level will drop, and I believe that will have a huge impact on pest management.
"As time goes on, SIT (sterile insect technology) will be a great option to manage Australian fruit pests, especially the fruit fly."
