In Rowan’s Social Insect Lab, researchers are examining whether gut bacteria play a role in fending off pathogens that threaten the honey bee population.
After more than a decade of crushing declines in the honey bee population worldwide, whole colonies of one of our most important pollinators are disappearing at unsustainable rates.
Svjetlana Vojvodic, assistant professor in the Department of Biological Sciences at Rowan University, believes that one part of the solution might be found in an unexpected place: inside the gut of the honey bee.
Could gut bacteria known as a gut microbiome hold the key to fending off colony-killing pathogens? That’s just one of the vital questions Vojvodic and her students are tackling in her Social Insect Lab in the College of Science & Mathematics csm.rowan.edu.
What bees’ gut microbiome is telling us
The honey bee’s gastrointestinal systems are colonized by billions of microbes composed of bacteria and fungi.
“All animals, including humans, have a distinct gut microbiome,” explained Vojvodic. “There are many different species of bacteria living in the gut, and they can influence everything from digestion to weight to behavioral disorders.” Most of those species are considered beneficial symbiotes – in other words, “good bacteria” that help, rather than harm, the host in which they are found.
In humans, hundreds of different species of bacteria – by some accounts, up to a thousand – make up the microbiome. In honey bees, the microbiome consists of just nine dominant bacterial groups.
“We know what these bacteria are in the honey bee, and we can manipulate them in my lab,” Vojvodic said. In doing so, she may just find a remedy against the common fungal pathogen of honey bees. This project will contribute to solving the global bee losses, including the most baffling beekeeping mystery in modern times: Colony Collapse Disorder (CCD).
A decade of unexplained colony collapses
In early spring of 2007, keepers around the world reopened their honey bee colonies after the winter’s hibernation to find something shocking: their bees were gone.
More specifically, the worker bees – the ones who perform the work needed to maintain and grow the colony, both within and outside the hive – had disappeared. The queen remained in the hive, along with the young, called the brood.
Typically, beekeepers find very few dead bees near these devastated hives. The remaining supplies of honey and pollen suggest that the worker bees didn’t simply starve over the winter. Yet their vanishing act is permanent. They never come back, and without the workers, the colony can’t survive for long.
As ongoing collapses have led to a drastic decline in managed honey bee populations across the globe, researchers have struggled to understand this disastrous phenomenon.
“A single cause of CCD hasn’t been identified,” Vojvodic said. Bee scientists now view CCD as the result of a combination of factors: a loss of diversity in the flowers that comprise a colony’s food supply, the harm caused to bees by agricultural pesticides and fungicides and a slew of worrying diseases.
Pathogens plaguing the honey bee population
“Bees have specific pathogens they have to fend off before winter,” explained Vojvodic. These pathogens can result from several different types of dangers, including exposure to viruses and “bad” bacteria – as opposed to the good bacteria found in gut microbes.
Perhaps the biggest threats come from parasites like the blood sucking Varroa destructor mite that can also transmit viruses. Very common also are fungal infections such as Ascosphaera apis, which is responsible for chalkbrood disease that affects bee larvae. As the young prepare to become adult bees within a wax-capped cell of the hive’s honeycomb, the fungus kills the infected bee, leaving behind what’s essentially a mummified corpse.
Many of the pathogens that infect honey bees currently have no cure. That’s one of the things Vojvodic’s research aims to change.
“Some bacteria present in honey bees’ guts can directly suppress fungi that can lead to deadly infections,” she said. “We’re trying to isolate specific compounds produced by gut microbes to understand which microbes influence these pathogens.”
The goal is to identify one microbe or compound that could be used as a medicine to help bees fend off the disease. “We have preliminary data saying that bees who have established normal gut microbiome survive longer when exposed to this fungal pathogen than those who don’t,” Vojvodic said.
One way to describe this occurrence is “extended immunity.” The bees gain protection from other organisms – the microscopic ones inhabiting their own guts.
Hands-on research for undergraduates
Since Vojvodic first established her lab in 2015, she has mentored 20 undergraduate students. Students gain a lot from their work in the Social Insect Lab, from cultivating hands-on research experience to having opportunities to deliver presentations at local and national conferences in the scientific community.
“I learned about the role of being a scientist, particularly the importance of sharing research with people who can make changes. Research in Dr. Vojvodic’s lab has given me the scientific skillset, professionalism, and confidence I have needed and will need in the future,” said Mathew Pekora, a 21-year-old senior biological science major from Delmont.
This month, Pekora and Olivia Smithson, also a senior biological science major, gave an award-winning poster presentation, “Behavioral consistencies of honey bee nurses,” at the Third Annual Evolution in Philadelphia Conference (EPiC) at Temple University.
“I don’t only speak for myself but for everyone who has done research under Dr. Vojvodic that it has been one of the most rewarding experiences we’ve had at Rowan,” Pekora said.
Vojvodic’s research into how gut microbes could affect fungal diseases in bees recently received a $40,000 funding grant from Project Apis m., a non-profit foundation whose name is taken from the scientific name for honey bees.
In so many ways, these studies are important – and not just for bees. The bee population decline has major implications for humans that go well beyond a shortage of honey.
“Bees pollinate a lot of the food we eat,” Vojvodic said. “If you don’t have pollinators, you’re not going to have apples, almonds and many other foods.”
Vojvodic’s research also could shed light on the interaction between diseases and good microbes that potentially occur in other organisms – even humans. Although gut microbes have been studied in several species, research into the interactions between these microbes and specialized pathogens is novel.
The worldwide decline in the bee population may be the most urgent area of Vojvodic’s bee research, but possible medicines aren’t the only focus of her work. These gut microbes also play a part in learning.
Honey bees are surprisingly smart, able to navigate of flight paths miles beyond their hives and communicate the locations of flowers to hive mates by performing a “waggle dance.” These intelligent insects can be trained through associative learning. Much like dogs learning to salivate at the sound of a bell, a bee can learn to stick out its proboscis, or “tongue,” upon smelling an odor it associates with the offering of a sugar-water reward.
Researchers have found that a bee’s gut microbiome affects how it learns. Laboratory bees that lack the beneficial microbes they would acquire naturally in a hive setting don’t learn as well as the bees who have a full microbiome. By isolating and testing different microbes, Vojvodic and her students discovered that one specific microbe increased bees’ abilities to learn.
“We don’t know why learning is affected,” Vojvodic said, which is why ongoing research into honey bee learning involves exploring brain gene expression. What’s clear is that the field of gut microbe research–in bees and other species–remains abuzz with opportunity.
Canada Welcomes the Return of Fumagillin to Combat Deadly Nosema Disease in Honey Bees.
A very effective treatment for Nosema, a deadly disease of honey bees, is now available again in Canada after intensive work by Vita Bee Health in conjunction with the Canadian Honey Council (CHC).
Fumagilin-B is a tried and tested preventative and curative antibiotic treatment for Nosema apis and Nosema ceranae. It first became available in the 1950s and was widely available in many countries until mid-2018, when the previous manufacturer, Medivet, ceased operations.
With the unavailability of fumagillin, beekeepers have been able to combat Nosema only by indirect methods such as protein feed supplements to boost immune defences, effective varroa control and regular comb changes. These are not always effective under harsh winter conditions. In Canada, because of the extreme low temperatures and long winters, the beehives have to be sealed and insulated from October to March – a long time for the bees to be confined and an ideal environment for Nosema to increase and spread through the colony. Canadian beekeepers were expecting severe winter colony losses if Fumagilin-B remained unavailable for this autumn/fall treatment season.
Now Canadian beekeepers again have access to fumagillin, manufactured in Canada and supplied by Vita Bee Health. The treatment should be administered with autumn/fall and spring feeds as necessary and, as ever, it is vital that beekeepers follow label directions precisely.
Rod Scarlett, executive director of the Canadian Honey Council, welcomed the news about the re-availability of Fumagillin-B saying, “If fumagillin wasn’t available, the consequences of Nosema infections would be dire. Many beekeepers think that without fumagillin we would expect over-wintering colony losses of 50% rather than 25%.”
Max Watkins, CEO of Vita Bee Health, said, “It’s been a long hard road to make Fumagillin-B available to beekeepers again and there’s still a lot of work to be done. We’re confident that we’re on our way to a sustainable supply of Fumagilin-B for Canada. The main reason that Fumagillin-B disappeared from the market place was the closure of the manufacturer when it faced a massive increase in the price of the active ingredient. Inevitably, Fumagilin-B is now more expensive than before, but beekeepers will quickly recognise that, set against colony losses, it is still a very cost-effective solution.”
Nosema apis and Nosema ceranae are parasitic microsporidian fungal pathogens. They can be identified only by microscopic analysis of the honey bee’s mid-gut. The spores multiply rapidly in the gut and can then spread throughout the colony. Nosema apis often leaves tell-tale signs of dysentery inside and more visibly on the outside of the hive (especially noticeable in spring), but the strain Nosema ceranae that originated in Asia often leaves no such traits. Research in Spain has shown that the disease can lead to a steady decline in bees over several months until the colony collapses. At that stage, other diseases such as chalkbrood and foulbrood may have become evident.
About Vita Bee Health
Vita Bee Health is a mite control and honeybee health specialist. It is the world’s largest dedicated supplier of honeybee health products to the honey and pollination industries. With a rigorous and ethical approach to research and development into honeybee health, Vita has no commercial interests in crop pesticides or crop breeding that may be harmful to honeybees.
Vita researches, develops, and manufactures a range of honeybee health products. Its headquarters are in the UK, it has offices in Italy, France and Russia, and partners across the globe. These products are marketed internationally through a network of 60 distributors in 50 countries.
Vita’s honeybee health product range includes anti-varroa acaricides – Apistan® (outside the USA/Canada) and Apiguard® – chalkbrood control, foulbrood diagnostic kits and health-promoting feeds. Vita also supplies Asian hornet traps, Small Hive Beetle traps, a Bee Gym varroa grooming aid and swarm lures. Vita products have been registered by more than 60 veterinary authorities.
Vita promotes sustainable beekeeping through Integrated Pest Management (IPM). Its treatments are designed to inhibit the build-up of resistance and wherever possible contain natural compounds and biological controls that are benign to all but the target pests.
Vita invests a very high proportion of its turnover in research and development. Research partners include universities such as Thessaloniki, Cardiff, Milan, Udine and Naples and institutes such as the FERA Laboratories in the UK and the USDA in America. Vita’s innovative research and development work has been recognised by and has received support from the UK Government.
As a result of its primary research of natural control agents, Vita is currently engaged in new projects exploring mite control in the agriculture, veterinary, and horticulture industries as well as public health and human allergen control.