Bees may be unknowingly transmitting a deadly virus between colonies, according to scientists.

A team of American researchers have found that Israeli Acute Paralysis Virus (IAPV) alters the ways the insects behave, causing them to sometimes allow intruder bees into the colony.

While the virus is well known, scientists have only  just discovered its effect on the bee’s defences, according to University of Adelaide ethologist Dr Katja Hogendoorn.

“Viruses have a tendency to make us change our behaviour to make us spread the virus,” Dr Hogendoorn says.

IAPV was first discovered in 2004, yet scientists are only just working out exactly how it spreads. It is thought to be the
the third-most common virus infection in bee colonies and Australian honeybees have also been found to contract the virus, according to Dr Hogendoorn.

The virus was thought to be introduced into the US by bees imported from Australia, but that was later proven not to be the case, says ScienceDaily.

DR Hogendoorn says honeybees would normally have defences to prevent an infection from spreading between hives.

The problem with this virus, is that it tricks the healthy bees into thinking their sick counterparts are well.

“It is interesting that a virus changes the behaviour, that the bees change their behaviour in response to the virus to make them less infective,” says Dr Hogendoorn.

The study, which was published in the prestigious science journal Proceeding of the National Academy of Sciences (PNAS), found that honeybees are twice as likely to allow in bees from other hives if the intruders are infected with IAPC.

Arizona State University entomologist Professor Adam Dolezal, who led the new research, said an a  EurekAlert statement: “The infected bees are able to circumvent the guards of foreign colonies, which they shouldn’t be able to do.”

Dr Hogendoorn believes that a lot can be learned from this new research.

“Yes, every virus does its own thing, but they are absolutely fascinating, all of them.”