In celebration of World Bee Day today (May 20), CSIRO researchers explain some of their diverse bee research, from using eDNA for early detection of varroa mite to working alongside bees as environmental monitors and detecting the floral sources of honey to understanding more about Australia’s 2000 species of native bees.
How is our research helping detect varroa mite?
“We’re developing eDNA testing protocols for honey and hive testing in collaboration with the University of Canberra, which will give early warning of varroa infection. It all comes down to the sensitivity of the testing method and making sure it’s accurate and efficient for field use,” Dr John Roberts, CSIRO Senior Research Scientist, said.
“With NSW DPI and researchers from the Australian National University, we’ve been analysing whole genome sequence data to trace the source of varroa mite in NSW. Genomic testing has provided valuable clues about where the incursion could have come from and how it has spread on arrival.
“Fortunately, our genome sequencing analysis has not detected Deformed Wing Virus (DWV) strains, which means Australia’s is still free of this high-priority pathogen. We did find several varroa mite viruses, but these are not known to negatively impact bee health.”
How can bees help with plant pest monitoring?
“The concept of using bees for plant pest surveillance came about when we realised just how much crop information we could tell from the pollen they collected in their honey-making and pollination tasks. Pollen is often a record of what pathogens are affecting the plants. By looking at pollen DNA, we can identify plant pathogens in that particular crop or orchard,” Dr Roberts said.
“Bee surveillance offers earlier detection of plant viruses than conventional monitoring methods. It also allows simultaneous surveillance of multiple plant pathogens and even pathogens affecting bees themselves.”
Why are bees such an important part of our ecosystem?
“Honey bees are key pollinators for food production, pollinating about a third of Australia’s food crops. Effective pollination reduces the cost of fruit and vegetable production, speeds up growth of plants to maturity and enhances yield,” Dr Roberts answered.
“Honey bees can also be used as plant pathogen monitors in horticulture, providing earlier detection of plant viruses than conventional monitoring methods.”
Can bees help study flowering plants?
“European honey bees are experts at surveying flowering plants. They bring pollen from each plant species they have visited back to their hives. We can collect that pollen and use DNA tests to identify the plants in the surrounding area,” Dr Liz Milla, Research Scientist at CSIRO’s Environomics Future Science Platform, said.
“The results of bee studies could help conserve rare species and detect weeds in hard-to-reach places.
“In a study published last year, we compared the results of people versus bees in a survey of flowering plants in Canberra. We found bees can detect more flowering plants than traditional surveys. But the plants detected by bees and people only overlapped by about 25 per cent. This means bees and people working together would give the best results.”
What is DNA testing of honey?
“DNA testing of honey can show where it was produced and what flowers the bees visited, thanks to the pollen DNA honey contains. The results could be used to confirm the floral composition and provenance of commercial honeys,” Dr Milla explained.
“We use a technique called pollen DNA metabarcoding. This is a way to identify plant species from their pollen by sequencing a short stretch of DNA and comparing it with a reference library of plant DNA.
“It’s a fast and accurate way to identify the floral composition of Australian honey compared with the traditional method of using microscopy to identify pollen in honey.”
Can bees help monitor environmental change?
“We have shown that bees have the potential to act as sentinels of our environment able to detect an enormous diversity of plants in very large areas,” Dr Francisco Encinas-Viso, CSIRO Senior Research Scientist, said.
“In Kosciuszko National Park, we analysed pollen DNA from pollinators, including bees and flies, to find out which plant species were flowering in the local area and which insect species were pollinating which plant species.
“The amazing outcome of this research is the possibility to track in time and space fine-scale changes in our ecosystems, which are particularly relevant to understand the impact of climate change.
How many species of native bees are there?
“The European honey bee, Apis mellifera, was introduced to Australia to pollinate crops. Australia also has around 2000 native bee species, but only 1653 have been scientifically named and described. We need more young people to study taxonomy and think about a career with bees,” Hymenoptera Research Scientist at CSIRO’s Australian National Insect Collection, Dr Juanita Rodriguez said.
“Australia’s native bees specialise in pollinating native plants. Very few have been studied for their ability to pollinate crops, but we do know that native bees are useful pollinators of mango, avocado, apple, tomato, raspberry and macadamia.
“Some of Australia’s native bees, like Blue-banded bees from the genus Amegilla are solitary species. Others, like sugarbag bees, Tetragonula carbonaria are social. Only about 0.6 per cent of native bee species make honey.”
What is the world’s biggest bee species?
“The biggest bee in the world is Wallace’s Giant Bee, Megachile pluto. Females are up to 38 mm long with a wingspan over 60 mm,” Dr Michael Elias, biosecurity specialist at CSIRO’s Australian National Insect Collection, answered.
“Females build hives in termite mounds, taking advantage of the protection afforded by the termite colony. They don’t make honey but do produce resin to protect their home. They can sting, but unlike European honey bees, they don’t die afterwards.
“Wallace’s Giant Bee species lives only on a small number of Indonesian islands. Despite being listed as vulnerable, specimens are collected and traded illegally. In the Australian National Insect Collection, we hold one specimen, which was intercepted by biosecurity officials last year.”
What’s next in bee research?
“My team is looking at the genetics of Varroa resistant honey bee genetics imported into Australia. This protective DNA will help beekeepers breed varroa tolerant bees. We’re looking at using genetic tests to track the protective DNA and make sure it gets inherited by the next generation of honey bees,” Dr Roberts said.
“We are investigating novel methods to do biosecurity surveillance of weeds using bees, eDNA and remote sensing technologies. This integrated approach will improve the management of early intervention of weed incursions,” Dr Encinas-Viso answered.
Why are bees such an important part of our ecosystem?
“Honey bees are key pollinators for food production, pollinating about a third of Australia’s food crops. Effective pollination reduces the cost of fruit and vegetable production, speeds up growth of plants to maturity and enhances yield,” Dr Roberts explained.
“Honey bees can also be used as plant pathogen monitors in horticulture, providing earlier detection of plant viruses than conventional monitoring methods.”
“The majority of flowering plants rely on insect pollinators, including honey bees and native bees, for reproduction. Pollination by insects is a vital ecosystem service, valued at billions of dollars per year,” Dr Milla added.
“We are using new genomic technologies, particularly DNA metabarcoding of mixed pollen samples, to substantially improve the resolution and accuracy of detection of species involved in pollen transport networks. This information can help us better target the management of key species in pollinator webs and assess the ability of plants and insects to respond to future disturbances.”
Dr Encinas-Viso said contrary to honey bees, most native bees are solitary and non-social.
“However, they play a crucial role in pollinating thousands of native plants across our diverse ecosystems as well as pollinating multiple crops such as macadamia, apples and blueberries,” Dr Encinas-Viso explained.
Are pollinator populations in decline, and what are some of the risk factors?
“There has been a global decline of pollinators due to a combination of interacting factors. It’s one of the most serious issues today relating to food security and biodiversity management,” Dr Milla answered.
“Native bees, like most insects, are at risk due to habitat fragmentation, use of pesticides and climate change and therefore, this threatens the maintenance of biodiversity and our food security,” Dr Encinas-Viso added.
