Do bees even care if UV pigmentation is changing in flowers?
Here’s some seemingly interesting news that came out this week: the UV pigmentation in flowers is changing as a result of climate change.
Researchers looked at hundreds of floral specimens, dozens of species, from across North America, Europe and Australia that had been collected between 1914 and 2017. They found that, on average, the pigmentation in these flowers increased 2% per year in all locations. However, they also found that the magnitude and direction of change in UV floral pigmentation was strongly connected to the shape of a flower, ozone levels and temperature. So some flower species increased their pigmentation while others decreased.
These pigments help protect flowers from being damaged by UV radiation, which is the basis of the researchers’ hypothesis for why these changes are occurring: the flowers are adapting to changes in ozone levels or temperature to maintain ideal protection for pollen and other important parts of the flower. But the UV light reflected from these pigments is something that bees can see, and it helps them locate the flowers they depend on. So if the pigments and resulting patterns of light are changing, what does this mean for bees?
“I don't really think that we have to worry about this too much,” says Lars Chittka, a professor of sensory and behavioral ecology, at Queen Mary, University of London, who has done extensive work on bee vision, cognition and evolution. “The colour and flower colour pattern preferences come about mostly via learning, and bees are fast learners.”
Chittka explains that it’s an old misconception that specific colors or patterns are inherently attractive to bees. While Nature does help shape floral preferences, most of the attraction is based on learning: bees learn which floral visual displays provide the greatest reward. Even native bee species who demonstrate an innate preference for violet-to-blue shades of flowers can have that preference rapidly overwritten by learning.
So bees seem more than capable of adjusting to any changes in floral UV pigmentation.
Chittka also offers two interesting and important critiques of this study. First, the authors used outdated and non-quantitative methods for assessing UV absorbance in the flowers. And second, as a result of their methodology, the authors didn’t distinguish between UVA rays (which are visible to bees) and UVB rays (which are not very visible to bees).
So it’s hard to even know if the results of this particular study are even meaningful to bees.
But here might be the most interesting thing to come out of this conversation. Chittka says his own work has shown that UV receptors were already present in the ancestor of all insects in the Cambrian period – millions of years before flowering plants even made an appearance on Earth – and that flower colors adapted to bee vision, not vice versa.
So maybe it’s flower species, and not quick-learning, opportunistic bees, that would be more at risk if floral UV displays are indeed changing.
Conservation
Why some ecologists worry about rooftop honey bee programs
(Wired) The growing interest in hobbyist beekeeping has some ecologists worried. The European honey bee, as its name might suggest, is not native to North America. While honey bees are a managed pollinator species, about 4,000 species of native bees also call the US home, including its urban areas. One group of researchers observed dozens of wild species across several Chicago neighborhoods, while another nature organization recorded more than 200 species in New York City. Now, some ecologists are concerned that with so much human help, the newcomers might outcompete their wild cousins, causing an ecological ripple effect that would threaten both the bees and the plants that depend on them.
Pollinator monitoring more than pays for itself
(EurekAlert, University of Reading) A new study found that the costs of running nationwide monitoring schemes are more than 70 times lower than the value of pollination services to the UK economy, and provide high quality scientific data at a much lower cost than running individual research projects.
Mountain butterflies ‘will have to be relocated as habitats get too hot’
(The Guardian) The diversity and resilience of cold-loving butterfly species is threatened by global heating which will destroy genetically unique populations, according to a study. Native mountain-dwelling butterflies such as the mountain ringlet, the bright-eyed ringlet and the dewy ringlet will have to be translocated to higher altitudes as their cooler habitat disappears to avoid extinction.
A new map shows where Asian giant hornets could thrive in the U.S.
(ScienceNews) Washington state officials are racing to find and kill ‘murder hornets’ before they can spread. Efforts are under way to catch a live hornet, attach a radio tag and track it back to a nest. The plan is to destroy the nest, hopefully before more hornets can start nests of their own hatch.
Economics
Beesharing start-up brings bees and German farmers together
(IamExpat) The start-up introduced a new service last year for farmers and their advisors. The platform allows them to indicate how large of an area they need pollinating, what crops are being grown and whether there are other agricultural fields in the immediate vicinity. This allows them to calculate how many bees are needed for their fields, as well as what kind of bees they need: mason bees, bumble bees or honey bees.
(FoodNavigator-USA) First came real milk proteins without cows, then egg proteins without chickens, and collagen without animals … and now honey, minus the bees? While the company won't discuss the details of the proprietary process, it confirms that synthetic biology and microbial fermentation are involved, technologies now deployed by a growing number of companies to produce everything from whey protein to vitamins.
Hand pollination, not agrochemicals, increases cocoa yield and farmer income
(ScienceDaily, University of Göttingen) Cocoa is in great demand on the world market, but there are many different ways to increase production. A research team has now investigated the relative importance of the use of pesticides, fertilizers and manual pollination in a well replicated field trial in Indonesian agroforestry systems. The result: an increase in both cocoa yield and farming income was achieved – not by agrochemicals, but by manual pollination.
Science
Pesticides and food scarcity dramatically reduce wild bee population
(UC Davis) A new study found that the combined threats reduced blue orchard bee reproduction by 57% and resulted in fewer female offspring. “In the bee world, males don’t matter so much. Male numbers rarely limit population growth, but fewer females will reduce the reproductive potential of subsequent generations.”
‘Cool’ sampling sites more likely to show false trends
(ScienceDaily, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig) Data collected by citizen science initiatives, museums and national parks is an important basis for research on biodiversity change. However, scientists found that sampling sites are oftentimes not representative, which may lead to false conclusions about how biodiversity changes. Their research calls for more objective site selection and better training for citizen scientists to prevent a site-selection bias.
One More Thing…
This, from ArnoldTortoise @arnoldtortoise via Twitter. “Ant’s antenna...”