January 14, 2010
Orchids of the Angraecum genus are famous—in evolutionary biology, at least—because of the comet orchid, A. sesquipedale, of Madagascar. After Charles Darwin examined this orchid, he hypothesized in 1862 that, based on the length of the flower’s nectar-spur, there would be a a moth with an equally long proboscis that could pollinate it. Darwin was right, though the moth, Xanthopan morgani, was not discovered until more than a decade after his death.
Now another orchid in this genus—A. cadetii—is revealing its own special secret: it’s the only flower known to be pollinated by a cricket.
A graduate student, Claire Micheneau, was studying Angraecum orchids and their pollinators on Reunion Island in the Indian Ocean in 2008. She knew from monitoring the pollen content of A. cadetii that something was pollinating it, but what could it be? Moths usually pollinate Angraecum orchids, like Darwin’s comet orchid, but Micheneau never saw one pollinating the plant during the day. What about at night?
Micheneau and another researcher rigged up a camera to take video at night. There was the pollinator, crawling around on the leaves and creeping into the flower itself: a raspy cricket of the Glomeremus genus and the first member of the order Orthoptera to be caught pollinating a plant. And like Darwin’s comet orchid and moth, the size of the cricket’s head matched up with the size of the nectar-spur opening in the flower.
When Micheneau studied how efficient the cricket was at its job, she found that A. cadetii had higher rates of pollination than two similar species pollinated by birds. Her study appears in the Annals of Botany.
Sign up for our free email newsletter and receive the best stories from Smithsonian.com each week.
No Comments »
No comments yet.