Planting wider variety of flowers could be key to saving the British bumblebee, says research
PLANTING a wide variety of flowers in gardens could save the great British bumblebee, according to new research.
It helps combat the spread of diseases that are wiping out the vital insect, say scientists.
The number of parasites is reduced when there are more species of pollinators and flowers.
Bee populations play a key role in production of a third of our food.
They have dropped around 17 per cent in Europe and 46% in the US in the last century.
Lead author Dr Peter Graystock, who is a biologist at Imperial College London, said: “We found when bee communities are at their most diverse, the proportion of infected bees were at their lowest.
“And when flowers were at their most abundant, fewer were likely to be acting as transmission hubs.”
His team analysed 110 and 89 species of bees and flowers respectively over the course of one growing season in three fields in New York.
They also measured the presence of five common parasites using molecular screening.
Dr Graystock said: “There are two things potentially occurring here.
“In diverse bee communities, parasites are more likely to end up in a species they are not compatible with, meaning they can’t replicate and spread further.
“The second thing is by having more flowers, bees aren’t all visiting and contaminating the same few flowers with high concentrations of parasites.”
Scans of more than 5,000 flowers and bees across a 24-week growing season showed 42% of the latter and 70% of the latter harboured at least one parasite.
But prevalence in bees was lowest early on when diversity was highest and there were fewer common social species like honeybees and bumblebees.
On the other hand it was lowest on flowers later in the year, when more had bloomed.
Dr Graystock said: “These findings suggest increasing the diversity of bee species and the number of flowers in natural communities may improve pollinator health by diluting the transmission of disease.”
Bees can be infected with a cocktail of parasites that can cause a range of symptoms from reduced foraging ability to dysentery and death.
The study, published in the journal Nature Ecology and Evolution, sheds fresh light on how parasites are fuelling the disappearance of bees. Flowers are essential for bee health, but also act as “transmission hubs” for diseases.
Dr Graystock added: “The power of this study is the number of bees and flowers screened over time, allowing us to see if the patterns fit with parasite transmission theory.”