Bacteria Can Protect Honeybees From Nutrition Deficiency, A Reason For Bee Population Decline

Researchers at Indiana University (IU), Bloomington, United States, have found an exceptional bacteria that feeds on honey bee larvae and fulfils the nutritional demands of developing honey bees. Nutrient deficiency is one of the reasons for the declining population of bees in the U.S.

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Humans depend on bees for food production. They help in agriculture through pollination. But for the past few decades, their population has been decreasing due to a lack of nutritional availability. According to a national survey, beekeepers in the U.S. have reported a colony loss of 40.5%.

“The effects of poor nutrition are most damaging in the developing larvae of honey bees, who mature into workers unable to meet the needs of their colony,” said Irene Newton, a professor at IU. “It is therefore essential that we better understand the nutritional landscape experienced by honey bee larvae.”

Honeybees collect pollen and nectar from various plants and flowers to keep their colonies alive. However, they lack floral diversity in the U.S.

“We’ve changed the way we use our land in the U.S.,” said Newton. “Now we have tons of monoculture crops like corn, which are wind pollinated and therefore no use to bees, covering acres and acres of land. Other crops that bees do pollinate are grown in monoculture as well, limiting the options for bees. “If you limit yourself to only eating one thing, that’s not healthy for you. You have to have a broad diet that will help fulfil all of your nutritional needs. Bees are the same way.”

Sister bees feed honey bee larvae with nectar, pollen and royal jelly (a nutrient-rich bee excretion). If larvae are expected to turn into queens, they’ll eat this jelly throughout their lives. However, if they become workers, they’ll feed pollen and nectar after some days. Besides being nutritious, royal jelly also has antimicrobial properties due to antimicrobial proteins, acidity and viscosity. If microbes are exposed to it, they’ll die.

Researchers have discovered a unique larvae-associated bacteria, Bombella apis or B.apis, that can flourish in royal jelly. They found that the bacteria increase the amino acid quantity in the jelly and make it more healthy for the larvae. This can decrease nutrition stress on developing bees.

“We have identified a nutritional symbiont of honey bees — a microbe that can help bolster the bees against nutrient scarcity and stress,” said Newton. “When we limited bee nutrition during development, we saw a drop in mass for the bees; bees were much smaller than their control counterparts. “When B. apis was added to these same bees, although they had poor nutrition, they reached the same mass as control bees given full nutrition. The microbe was able to make up for the poor diet. This suggests that B. apis could be added to colonies as a probiotic to protect from nutritional stress.”

The results indicate that beekeepers may use B.apis to counter poor nutrient levels in honeybees. B.apis can exist in carbohydrate or sugar-rich medium for 24 hours, so beekeepers can add it to their bees’ diet.

“We are excited to explore the other interactions that B. apis has in a colony, to better understand what it’s doing in different environments and the role it plays in association with honey bee queens,” said Newton.

The research has been published in the journal The International Society for Microbial Ecology (ISME) Journal.