Bee semen antibodies could protect hives from sexually transmitted disease
Thursday 21 January 2016 00.01 EST Last modified on Thursday 21 January 2016 00.11 EST
Scientists have discovered antibodies in bee semen that could help protect commercial hives from a potentially deadly sexually transmitted disease.
The immune proteins, which protect queen bees from the fungus after mating, were identified by researchers at the Western Australian Centre for Integrative Bee Research.
The director of the centre, Prof Boris Baer, said the discovery showed that honeybees had a sophisticated immune system and could potentially breed to be resistant to certain pathogens, which could help prevent the worldwide decline in bee numbers.
The Nosema apis fungus is transmitted through sexual contact and also contact between worker bees, who rub up against spores shed around flowers. It works its way into the digestive stomach of infected bees and damages the gut, which can be deadly when combined with other stresses.
It is closely related to Nosema ceranae, a strain that was discovered in Asia but is spreading as the global climate warms, according to British study released last year.
“The bees very rarely have sex, only the queen will sex and then only once in her life, so most of the time the Nosema is not spread through sexual contact, it is worker-to-worker,” Baer told the Guardian.
The immune proteins were discovered when researchers were examining bee semen to find a cure to declining rates of bee fertility in Western Australia, which have stemmed from 30 years of inbreeding. It provided “a very elegant solution” for researchers, Baer said, because it was easier to put seminal fluid under a microscope.
“We can basically examine the function of the immune system outside of the bee, which believe me is much simpler than examining it in the entire bee,” he said.
One of the proteins attacks the fungal spores by tricking it into germinating early while a second kills the spores outright.
“If we use the seminal fluid against other microbes, things that are really ubiquitous like yeast, it’s not killing those microbes, it’s really only responding to this disease,” he said. “There’s a great degree of specificity there.”
Evidence of a sophisticated immune response could mean that scientists could isolate and breed for a higher resistance to other pathogens, such as the deadly Varroa destructor mite, known as the “bee super-killer”.
“Sooner or later we will find the bee that is able to defend against Varroa and that will be a much better approach than us throwing chemicals at the bees all the time, which can weaken the bees and also find their way into honey, which people don’t like,” Baer said.
“For us it’s very exciting because if we are looking at bees, the worldwide population of bees is declining, which has impacts on plant pollination and agriculture. Pathogens play a major role in that decline and here we find the bee is able to defend itself.”
Australia is the only Varroa-free continent left, which makes Australian bees particularly vulnerable to localised extinctions if the parasite is introduced.
Scientists at Australia’s the Commonwealth Scientific and Industrial Research Organisation are attempting to develop a breed of honeybee that is immune to the mite and customs officers have cracked down on illegal bee importation to prevent the mite from crossing Australian borders.