Sick bees will actively select for better food, study shows.
Being sick as an adult is quite a depressing experience. Not only do you feel horrible, but you have to call all sorts of people to let them know you won’t be coming in to work today, or that you’ll be paying them a visit at the clinic, respectively. You have to go get your own meds, make sure you’re staying hydrated — all in all, it’s a hassle, and often, we can’t really afford to take that sick leave. So we bear and power through it.
Bees, however, take good care of themselves when sick. A team led by Dr. Lori Lach, Senior Lecturer at JCU, reports that the black-and-yellow critters will actually select better food when sick, to get an extra energy boost.
For the study, the team worked with some healthy bees (as controls), others infected with the gut parasite Nosema ceranae, and compared their feeding habits. Nosema ceranae is one of the most widespread parasites of adult honey bees in the world, and its effects on the host bee’s physiology has been studied at length. However, this is “the first study we’re aware of to investigate effects on floral choice,” said Dr. Lach.
“The question then was — when the bees had the opportunity to select their own food, would they choose what was good for them?” said Jade Ferguson, the student who conducted the project for her Honours degree.
The team gave the bees artificial flowers to forage from, which housed either high-quality pollen (which was more nutritious and had a higher calorie count), low-quality pollen, or sugary water. Overall, the researchers report that healthy bees showed no preference for either type of pollen. However, twice as many infected bees picked the higher quality pollen over the lower quality one.
To their surprise, the team found that sick bees lived longer than healthy ones when they had access to the more nutritious pollen — even though it also increased the parasite count in their guts. This suggests that their preference for the higher-quality pollen stems from a bid to counteract the negative effects of the parasites.
It’s still unclear how the bees distinguish between pollens of different quality. However, the team believes that the bees’ preferences will affect what native and crop flowers the insects visit, as they can vary greatly in the quality of pollen offered. Since plants often compete for pollinators, the findings can be used to estimate which plants (both crops and wild) will be visited by a given colony. Parasite presence, the team reports, seems to be the only factor that influences which flowers are visited.
The paper “Honey Bee (Apis mellifera) Pollen Foraging Reflects Benefits Dependent on Individual Infection Status” has been published in the journal Microbial Ecology.