Bees tagged with Radio-Frequency Identification RFID chips have given Australian scientists new insight into how disease affects the communal insects.
The team from James Cook University used the wireless communication technology to track 960 bees over their lifetime, half of whom had been infected with a low dose of nosema spores – a fungal gut parasite common amongst adult honeybees.
The nosema species used has long been considered relatively benign, but the researchers found infected bees were 4.3 times less likely to be carrying pollen than uninfected bees. Infected bees also carried less pollen when they did, started working later, stopped working sooner and died younger.
“No one had looked at bees at this level before, to see what individual bees do when they are sick,” said Dr Lori Lach, lead author of a study published in the Journal of Invertebrate Pathology.
“The real implications from this work are for humans. About a quarter of our food production is dependent on honey bee pollination. Declines in the ability of honey bees to pollinate will result in lower crop yields.”
Half of the insects were infected with a low dose of nosema spores and by combining data from the RFID tags with observations at the hives and artificial flowers, the researchers were able to compare the bees work rate and determine what kind of material they gathered.
The infected bees are outwardly indistinguishable from non-infected bees according to Lach, and as nosema is considered fairly harmless compared to other parasites and pathogens that infect honey bees, no one had previously investigated the effect of a low dose on behaviour.
“We knew dead bees couldn’t forage or pollinate,” said Dr Lach. “But what we wanted to investigate was the behaviour of live bees that are affected by non-lethal stressors.”
Using RFID tags allowed the bees to be monitored individually for the first time, but actually attaching them to such a tiny animal was quite a challenge according to Dr Lach.
She said: “We just had to hold them in our hands and hope the glue dried quickly. It was actually quite a process – they had to be individually painted, then individually fed, then the tag was glued on, then they were individually scanned so we knew which tag was on what colour and treatment bee and which hive it was going into.
"It all had to happen within about eight hours of emergence because as the day goes on they start learning how to fly and they get better at stinging.”